bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design, Synthesis, and Evaluation of 3‐Aryl‐4‐pyrrolyl‐maleimides as Glycogen Synthase Kinase‐3β Inhibitors
Authors: Ye Qing , Li Meng , Zhou Yu‐Bo , Cao Jia‐Yu , Xu Lei , Li Yu‐Jin , Han Liang , Gao Jian‐Rong , Hu Yong‐Zhou , Li Jia 
Published: April 2013

AbstractA series of 3‐aryl‐4‐pyrrolyl‐maleimides were designed, synthesized, and evaluated for their glycogen synthase kinase‐3β (GSK‐3β) inhibitory activity. Most compounds exhibited potent activity against GSK‐3β. Among them, compounds 11a, 11c, 11h, 11i, and 11j significantly reduced Aβ‐induced Tau hyperphosphorylation, showing the inhibition of GSK‐3β at the cellular level. Structure–activity relationships were discussed based on the experimental data obtained.
Exponential Stability and Asynchronous Stabilization of Switched Systems With Stable and Unstable Subsystems
Authors: Zhang Hongbin , Mao Yanbing , Gao Yansong 
Published: April 2013

AbstractThis paper deals with the exponential stability and asynchronous stabilization of continuous‐time switched systems. By delicately constructed piecewise Lyapunov‐like functions and the minimum dwell time switching method, exponential stability of the switched systems with stable or unstable subsystems is obtained. Based on the result of the stability, the problem of controller design of the switched systems under asynchronous switching is also solved, and the delay that causes asynchronous phenomena can be unbounded. The stability results and control laws of the switched systems are formulated in the form of linear matrix inequalities that are numerically feasible. Finally, two illustrative numerical examples are presented to show the effectiveness of the obtained theoretical results.
A Nonlinear Observer Based Analytical Redundancy for Predictive Fault Tolerant Control of a Steer‐by‐Wire System
Authors: Anwar Sohel , Niu Wei 
Published: April 2013

AbstractIn this paper, a nonlinear sliding mode observer, along with a long range linear predictor, is presented for fault tolerant control of a steer by wire system. The long‐range predictor is based on Diophantine identity aimed at improving the fault detection efficiency. The overall predictive fault tolerant control strategy was then implemented and validated on a steer by a wire hardware in loop bench. The experimental results show that the overall robustness of the steer by wire system was not sacrificed through the usage of analytical redundancy for sensors along with the designed fault detection, isolation, and identification algorithm. Moreover, the experimental results indicated that the fault detection speed is improved using the proposed analytical redundancy‐based algorithms for both attenuating and amplifying type faults. The proposed fault detection algorithm was also found to be robust against a wide range of fault types.
Effect of 1 mT sinusoidal electromagnetic fields on proliferation and osteogenic differentiation of rat bone marrow mesenchymal stromal cells
Authors: Liu Chaoxu , Yu Jizhe , Yang Yong , Tang Xiangyu , Zhao Dongming , Zhao Wenchun , Wu Hua 
Published: April 2013

AbstractElectromagnetic field (EMF) stimulation is clinically beneficial for fracture nonunion and a wide range of bone disorders. However, no consensus has been reached on the optimal parameters of the EMF. The exact mechanism by which EMFs enhance osteogenesis has also not been defined. In the present study, a sinusoidal 1 mT EMF at frequencies of 10, 30, 50, and 70 Hz were administered to rat bone marrow mesenchymal stromal cells (rBMSCs) in the cyclic mode of 2 h exposures followed by 4 h of culture without exposure. The cell viability, proliferation, expression of some osteogenic genes, and mineralization of the extracellular matrix were investigated. It was found that the cell viability was decreased by EMF exposures of 50 and 70 Hz. The proliferation of rBMSCs was elevated significantly in the 10 Hz EMF‐treated group during the culture periods. The expression of alkaline phosphatase (ALP) and osteocalcin (OC), two early‐phase osteogenic differentiation markers, was up‐regulated by the 1 mT, 10 Hz EMF after 1 week. However, the expression of genes that marked the later‐phase osteogenic differentiation and maturation of osteoblasts was elevated by the stimulation of 50 Hz EMFs after 2 weeks. In addition, it was observed that the mineralization of the extracellular matrix was enhanced by 50 Hz EMF exposure. These results indicated that the 1 mT EMF at different frequencies had disparate effects on the viability, proliferation and osteogenic differentiation of rBMSCs, and may be beneficial for developing novel therapeutic approaches in bone regenerative medicine. Bioelectromagnetics. 34:453–464. © 2013 Wiley Periodicals, Inc.
Introduction altmetrics: What, why and where?
Authors: Piwowar Heather 
Published: April 2013

AbstractEditor's SummaryThe ASIS&T Bulletin special section on altmetrics presents alternative metrics as a new and critically needed approach to measuring the impact of scholarly research. With long‐established citation‐based metrics unable to capture the increasing variety of online references to a scholar's work, alternative indicators offer a different view of the influence of that work. Contributed papers demonstrate how altmetrics can work on a personal level to enhance a scholar's CV and on a broad, even global level, to transform scholarly communication through its interaction with open access, digital repositories and research in emerging countries. One article suggests altmetrics should soon be included among mainstream metrics, and other contributions describe specific indicators and altmetric software considerations. The need for innovative measurement and the advantages of altmetrics in particular bode well for their wide acceptance and continuing development.
Terpene‐Derived Bifunctional Thioureas in Asymmetric Organocatalysis
Authors: Narayanaperumal Senthil , Rivera Daniel G. , Silva Rodrigo C. , Paixão Márcio W. 
Published: April 2013

AbstractChiral hydrogen‐bond donors have played a crucial role in the progress of asymmetric catalysis as an essential tool in modern organic synthesis. Among these donors, thioureas have been found to be one of the most powerful systems in organocatalytic approaches. Within the last three years, a new generation of bifunctional thiourea catalysts has emerged as an effective way to promote highly demanding chemical transformations, frequently with success rates that are intriguingly higher than with other traditional thioureas. This new class of organocatalysts incorporates a bulky, rigid, and chiral terpene skeleton as one of the thiourea substituents, thus providing an additional and effective rigidifying (entropic) effect on the electrophile activation profile of thioureas. Structural integrations, either with additional Lewis basic nucleophile‐activating motifs or with amino groups for enamine catalysis, have enabled their implementation in a wide repertoire of stereocontrolled catalytic processes. This Review charts the development of these new catalysts, as well as their applications in a wide variety of reactions and reaction sequences, with the hope of encouraging further progress in the field of thiourea‐catalyst discovery and of bringing attention to the countless possibilities that are opened up by the tremendous success of terpene‐derived thiourea catalysts.
The Molecular Pathway to ZIF‐7 Microrods Revealed by In Situ Time‐Resolved Small‐ and Wide‐Angle X‐Ray Scattering, Quick‐Scanning Extended X‐Ray Absorption Spectroscopy, and DFT Calculations
Authors: Goesten Maarten , Stavitski Eli , Pidko Evgeny A. , Gücüyener Canan , Boshuizen Bart , Ehrlich Steven N. , Hensen Emiel J. M. , Kapteijn Freek , Gascon Jorge 
Published: April 2013

AbstractWe present an in situ small‐ and wide‐angle X‐ray scattering (SAXS/WAXS) and quick‐scanning extended X‐ray absorption fine‐structure (QEXAFS) spectroscopy study on the crystallization of the metal–organic framework ZIF‐7. In combination with DFT calculations, the self‐assembly and growth of ZIF‐7 microrods together with the chemical function of the crystal growth modulator (diethylamine) are revealed at all relevant length scales, from the atomic to the full crystal size.
Interaction Modes and Absolute Affinities of α‐Amino Acids for Mn2+: A Comprehensive Picture
Authors: Khodabandeh M. Hassan , Reisi Hamid , Davari Mehdi D. , Zare Karim , Zahedi Mansour , Ohanessian Gilles 
Published: April 2013

AbstractManganese is involved as a cofactor in the activation of numerous enzymes as well as the oxygen‐evolving complex of photosystem II. Full understanding of the role played by the Mn2+ ion requires detailed knowledge of the interaction modes and energies of manganese with its various environments, a knowledge that is far from complete. To bring detailed insight into the local interactions of Mn in metallopeptides and proteins, theoretical studies employing first‐principles quantum mechanical calculations are carried out on [Mn‐amino acid]2+ complexes involving all 20 natural α‐amino acids (AAs). Detailed investigation of [Mn‐serine]2+, [Mn‐cysteine]2+, [Mn‐phenylalanine]2+, [Mn‐tyrosine]2+, and [Mn‐tryptophan]2+ indicates that with an electron‐rich side chain, the most stable species involves interaction of Mn2+ with carbonyl oxygen, amino nitrogen, and an electron‐rich section of the side chain of the AA in its canonical form. This is in sharp contrast with aliphatic side chains for which a salt bridge is formed. For aromatic AAs, complexation to manganese leads to partial oxidation as well as aromaticity reduction. Despite multisite binding, AAs do not generate strong enough ligand fields to switch the metal to a low‐ or even intermediate‐spin ground state. The affinities of Mn2+ for all AAs are reported at the B3LYP and CCSD(T) levels of theory, thereby providing the first complete series of affinities for a divalent metal ion. The trends are compared with those of other cations for which affinities of all AAs have been previously obtained.
Nonlinear Absorption Dynamics Using Field‐Induced Surface Hopping: Zinc Porphyrin in Water
Authors: Röhr Merle I. S. , Petersen Jens , Wohlgemuth Matthias , Bonačić‐Koutecký Vlasta , Mitrić Roland 
Published: April 2013

AbstractWe wish to present the application of our field‐induced surface‐hopping (FISH) method to simulate nonlinear absorption dynamics induced by strong nonresonant laser fields. We provide a systematic comparison of the FISH approach with exact quantum dynamics simulations on a multistate model system and demonstrate that FISH allows for accurate simulations of nonlinear excitation processes including multiphoton electronic transitions. In particular, two different approaches for simulating two‐photon transitions are compared. The first approach is essentially exact and involves the solution of the time‐dependent Schrödinger equation in an extended manifold of excited states, while in the second one only transiently populated nonessential states are replaced by an effective quadratic coupling term, and dynamics is performed in a considerably smaller manifold of states. We illustrate the applicability of our method to complex molecular systems by simulating the linear and nonlinear laser‐driven dynamics in zinc (Zn) porphyrin in the gas phase and in water. For this purpose, the FISH approach is connected with the quantum mechanical‐molecular mechanical approach (QM/MM) which is generally applicable to large classes of complex systems. Our findings that multiphoton absorption and dynamics increase the population of higher excited states of Zn porphyrin in the nonlinear regime, in particular in solution, provides a means for manipulating excited‐state properties, such as transient absorption dynamics and electronic relaxation.
Platinum‐ and Membrane‐Free Swiss‐Roll Mixed‐Reactant Alkaline Fuel Cell
Authors: Aziznia Amin , Oloman Colin W. , Gyenge Előd L. 
Published: April 2013

AbstractEliminating the expensive and failure‐prone proton exchange membrane (PEM) together with the platinum‐based anode and cathode catalysts would significantly reduce the high capital and operating costs of low‐temperature (<373 K) fuel cells. We recently introduced the Swiss‐roll mixed‐reactant fuel cell (SR‐MRFC) concept for borohydride–oxygen alkaline fuel cells. We now present advances in anode electrocatalysis for borohydride electrooxidation through the development of osmium nanoparticulate catalysts supported on porous monolithic carbon fiber materials (referred to as an osmium 3D anode). The borohydride–oxygen SR‐MRFC operates at 323 K and near atmospheric pressure, generating a peak power density of 1880 W m−2 in a single‐cell configuration by using an osmium‐based anode (with an osmium loading of 0.32 mg cm−2) and a manganese dioxide gas‐diffusion cathode. To the best of our knowledge, 1880 W m−2 is the highest power density ever reported for a mixed‐reactant fuel cell operating under similar conditions. Furthermore, the performance matches the highest reported power densities for conventional dual chamber PEM direct borohydride fuel cells.
Multi‐factor climate change effects on insect herbivore performance
Authors: Scherber Christoph , Gladbach David J. , Stevnbak Karen , Karsten Rune Juelsborg , Schmidt Inger Kappel , Michelsen Anders , Albert Kristian Rost , Larsen Klaus Steenberg , Mikkelsen Teis Nørgaard , Beier Claus , Christensen Søren 
Published: April 2013

AbstractThe impact of climate change on herbivorous insects can have far‐reaching consequences for ecosystem processes. However, experiments investigating the combined effects of multiple climate change drivers on herbivorous insects are scarce. We independently manipulated three climate change drivers (CO2, warming, drought) in a Danish heathland ecosystem. The experiment was established in 2005 as a full factorial split‐plot with 6 blocks × 2 levels of CO2 × 2 levels of warming × 2 levels of drought = 48 plots. In 2008, we exposed 432 larvae (n = 9 per plot) of the heather beetle (Lochmaea suturalis Thomson), an important herbivore on heather, to ambient versus elevated drought, temperature, and CO2 (plus all combinations) for 5 weeks. Larval weight and survival were highest under ambient conditions and decreased significantly with the number of climate change drivers. Weight was lowest under the drought treatment, and there was a three‐way interaction between time, CO2, and drought. Survival was lowest when drought, warming, and elevated CO2 were combined. Effects of climate change drivers depended on other co‐acting factors and were mediated by changes in plant secondary compounds, nitrogen, and water content. Overall, drought was the most important factor for this insect herbivore. Our study shows that weight and survival of insect herbivores may decline under future climate. The complexity of insect herbivore responses increases with the number of combined climate change drivers.
Dinuclear Monomeric and Macrocyclic Organotin Dithiocarbamates Derived from 1,10‐Diaza‐18‐crown‐6 and 4,4′‐Trimethylenedipiperidine
Authors: Celis Norma A. , Villamil‐Ramos Raul , Höpfl Herbert , Hernández‐Ahuactzi Irán F. , Sánchez Mario , Zamudio‐Rivera Luis S. , Barba Victor 
Published: April 2013

Abstract1,10‐Diaza‐18‐crown‐6 and 4,4′‐trimethylenedipiperidine were transformed into bis‐dithiocarbamate ligands, which were then reacted in situ with different di‐ and triorganotin(IV) chlorides to generate dinuclear monomeric or macrocyclic products. The identity of the compounds was established by elemental analysis, multinuclear NMR spectroscopy (1H, 13C, and 119Sn), IR spectroscopy, mass spectrometry, and for representative examples additionally by single‐crystal X‐ray diffraction analysis. In combination with DFT calculations, the structural characterization showed that diaryltin and dialkyltin fragments give macrocycles of different conformation owing to changes in the coordination stereochemistry (cis vs. trans isomers). The macrocycle cavities are suitable for the inclusion of guest molecules. At the supramolecular level, the Sn complex molecules are linked through intermolecular C–H···S and C–H···Cl interactions in the solid state.
Application of the Wharton Rearrangement for the de novo Synthesis of Pyranosides with ido, manno, and colito Stereochemistry
Authors: Cuccarese Michael F. , Wang Hua‐Yu Leo , O'Doherty George A. 
Published: April 2013

AbstractA de novo asymmetric synthesis of α‐ido‐pyranosides, as well as several deoxy and amino variants, has been achieved. The procedure involves a palladium(0)‐catalyzed glycosylation in combination with a Wharton rearrangement/epoxide‐opening reaction sequence to access sugars with ido, manno, and colito stereochemistry as well as several azido analogues.
Extending the Scope of the Aza‐Fischer Synthesis of 4‐ and 6‐Azaindoles
Authors: Thomae David , Jeanty Matthieu , Coste Jérome , Guillaumet Gérald , Suzenet Franck 
Published: April 2013

AbstractFischer indole cyclization has recently been described as an efficient approach to the synthesis of azaindoles bearing electron‐donating groups. We now show that this cascade reaction can be very efficient for the formation of a wider range of 4‐ and 6‐azaindoles by using microwave irradiation.
Generation of Trityl Radicals by Nucleophilic Quenching of Tris(2,3,5,6‐tetrathiaaryl)methyl Cations and Practical and Convenient Large‐Scale Synthesis of Persistent Tris(4‐carboxy‐2,3,5,6‐tetrathiaaryl)methyl Radical
Authors: Rogozhnikova Olga Yu. , Vasiliev Vladimir G. , Troitskaya Tatiana I. , Trukhin Dmitry V. , Mikhalina Tatiana V. , Halpern Howard J. , Tormyshev Victor M. 
Published: April 2013

AbstractTris(2,3,5,6‐tetrathiaaryl)methyl cations, which were generated from the corresponding triarylmethanols in the presence of strong acids, underwent reaction with nucleophiles to give trityl radicals, as the product of a one‐electron reduction of the carbocation. Depending on the nature of the nucleophile, the only byproducts were either diamagnetic quinone methides or asymmetrical monosubstituted trityl radicals. Herein, we report a protocol for the large‐scale synthesis of the Finland trityl, which has the advantage of high overall yield and reproducibility.
The First ZnII‐Catalyzed Oxidative Amidation of Benzyl Alcohols with Amines under Solvent‐Free Conditions
Authors: Wu Xiao‐Feng , Sharif Muhammad , Pews‐Davtyan Anahit , Langer Peter , Ayub Khurshid , Beller Matthias 
Published: April 2013

AbstractThe first zinc‐catalyzed oxidative amidation of benzyl alcohols has been developed. Both aliphatic and aromatic amines can be tolerated and applied in this reaction. Various amides were prepared in good yields under solvent‐free and mild conditions.
Direct Electrochemistry of Cytochrome c Based on Poly(diallyldimethylammonium Chloride)‐ Graphene Nanosheets/Gold Nanoparticles Hybrid Nanocomposites and Its Biosensing
Authors: Song Yonghai , Liu Hongyu , Wan Lingli , Wang Yu , Hou Haoqing , Wang Li 
Published: April 2013

AbstractA novel biosensor was developed by entrapping cytochrome c (Cyt c) in thin films of the room temperature ionic liquid (RTIL) containing nanocomposites of poly(diallyldimethylammonium chloride)‐graphene nanosheets‐gold nanoparticles (PDDA‐Gp‐AuNPs) at a 11‐mercaptoundecanoic acid‐6‐mercapto‐1‐hexanol modified gold electrode. The synthesized PDDA‐Gp‐AuNPs hybrid nanocomposites were characterized by UV‐vis spectroscopy, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. The PDDA‐Gp‐AuNPs nanocomposites could increase the effective surface of the electrode, enhance the fixed amount of Cyt c on the electrode surface, promote the electron transfer and facilitate the catalytic activity of Cyt c. The RTIL could provide a biocompatible microenvironment to keep Cyt c biological activities, act as an effective mediator to immobilize a large number of Cyt c on the electrode and have good conductivity to improve electron transfer. Therefore, the resultant electrode exhibited good electrochemical performance and electrocatalytic activity. It could be used for electrochemical detection of H2O2 with rapid response, high sensitivity, wide linear range and low detection limit, as well as good stability, repeatability and selectivity. The sensor might be promising for practical application.
Graphene Decorated with Nickel Nanoparticles as a Sensitive Substrate for Simultaneous Determination of Sunset Yellow and Tartrazine in Food Samples
Authors: Gan Tian , Sun Junyong , Wu Qiong , Jing Qiangshan , Yu Sheng 
Published: April 2013

AbstractIn this paper, ultrathin graphene (GN) nanosheets were uniformly decorated with nickel (Ni) nanoparticles, as confirmed by scanning electron microscopy and transmission electron microscopy. This GNNi hybrid exhibited excellent accumulation and catalytic capacity for the simultaneous detection of sunset yellow and tartrazine, two colorants commonly found mixed in foodstuffs. The electrochemical reaction mechanism of sunset yellow and tartrazine were studied in detail on the GNNi nanocomposite modified glassy carbon electrode. In square wave voltammetry measurements, the oxidation peak potentials of sunset yellow and tartrazine were separated by about 250 mV. This novel proposed voltammetric method has good selectivity which was successfully applied for the simultaneous determination of sunset yellow and tartrazine in some food sample extracts.
ECOSYSTEM SERVICES AND THE PROTECTION, RESTORATION, AND MANAGEMENT OF ECOSYSTEMS EXPOSED TO CHEMICAL STRESSORS
Authors: Maltby Lorraine 
Published: April 2013

Abstract

Ecosystem services—the benefits people obtain from ecosystem structures and processes—are essential for human survival and well-being. Chemicals are also an essential component of modern life; however, they may cause adverse ecological effects and reduce ecosystem service provision. Environmental policy makers are increasingly adopting the ecosystem services concept, but applying this approach to the protection, restoration, and management of ecosystems requires the development of new understanding, tools, and frameworks. There is an urgent need to understand and predict the effect of single and multiple stressors on ecosystem service delivery across different spatial scales (local to global), to develop indicators that can be used to quantify and map services and identify synergies and trade-offs between them, to establish protection goals and restoration targets defined in terms of the types and levels of service delivery required, and to develop approaches for the assessment and management of chemical risk to ecosystem services that consider the whole life cycle of products and processes. These are major research challenges for the environmental science community in general and for ecotoxicologists and risk assessors in particular. Environ. Toxicol. Chem. 2013;32:974–983. © 2013 SETAC
Complex adult laryngotracheal reconstruction with a prefabricated flap: A case series
Authors: Detwiller Kara Y. , Schindler Joshua S. , Schneider Daniel S. , Lindau Robert , Wax Mark K. 
Published: April 2013

BackgroundLaryngotracheal stenosis (LTS) can cause persistent or recurrent airway obstruction. Although there is extensive literature on surgical techniques to treat LTS at onset, there are few techniques described for complex adult LTS after failed prior airway surgery. We describe a procedure used successfully in 3 patients who required structural augmentation for complex LTS.MethodsPatients were treated with staged reconstruction using a prefabricated composite graft consisting of auricular cartilage and a radial forearm free flap.ResultsAll patients underwent successful reconstruction with good wound healing and are tolerating oral diets. Two patients have been successfully decannulated.ConclusionA delayed prefabricated graft using auricular cartilage in a radial forearm free flap is a viable surgical intervention in patients with complex adult LTS who are not candidates for conventional approaches. © 2013 Wiley Periodicals, Inc. Head Neck 35: E376–E380, 2013