bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of 2D inviscid, adiabatic, compressible flows on emulated digital CNN‐UM
Authors: Kocsárdi Sándor , Nagy Zoltán , Csík Árpád , Szolgay Péter 
Published: November 2008

AbstractIn the area of mechanical, aerospace, chemical and civil engineering the solution of partial differential equations has been one of the most important problems in mathematics for a long time. In this field, one of the most exciting areas is the simulation of fluid flow, which involves for example, problems of air, sea and land vehicle motion. In this paper a CNN‐UM based solver of 2D inviscid, adiabatic, compressible fluids will be presented. The governing equations are solved by using first‐ and second‐order numerical methods. Unfortunately the necessity of the coupled multi‐layered computational structure with nonlinear, space‐variant templates does not make it possible to utilize the huge computing power of the analog CNN‐UM chips. To improve the performance of our solution emulated digital CNN‐UM implemented on FPGA has been used. Properties of the implemented specialized architecture is examined in terms of area, speed and accuracy. Copyright © 2008 John Wiley & Sons, Ltd.
The winnerless competition paradigm in cellular nonlinear networks: Models and applications
Authors: Arena Paolo , Fortuna Luigi , Lombardo Davide , Patanè Luca , Velarde Manuel G. 
Published: November 2008

AbstractStarting from the biological background on the olfactory architecture of both insects and mammalians, different nonlinear systems able to respond to spatial‐distributed external stimuli with spatial–temporal dynamics have been investigated in the last decade. Among these, there is a class of neural networks that produces quasi‐periodic trajectories that pass near heteroclinic contours and prove to be global attractors for the system. For this reason, these networks are calledwinnerless competition(WLC) networks. The sequence of saddle points crossed by each trajectory depends on the spatial input presented to the network and can be used as a ‘code’ representing a specific class of stimuli. Thanks to the intrinsic discrimination, WLC networks are often used for classification. In this paper, this capability is exploited within a framework for action‐oriented perception. WLC networks are here used as bio‐inspired architectures for the association between stimuli and ‘percepts’. After presenting the theoretical basis of the WLC network in the classic Lotka–Volterra system, we investigate how WLC networks can be formalized in terms of cellular nonlinear networks (CNNs) hosting different kinds of cells: the FitzHugh–Nagumo neuron, the Izhikevich neuron and the single layer CNN standard cell. In order to find efficient ways to code environmental stimuli for action generation, we analyze and compare these WLC‐based CNNs in terms of number of generated classes and robustness against the initial conditions. Based on the simulation results, we apply the best‐performing system to solve a perceptual task involving navigation and obstacle avoidance. We demonstrate how the large memory capacity shown by the WLC–CNN is able to contribute to the new perceptual framework for autonomous artificial agents, where the association between stimuli and sequences is learned through the experience. Copyright © 2008 John Wiley & Sons, Ltd.
Structural Studies on (–)‐Sparteine‐Coordinated Lithiosilanes
Authors: Däschlein Christian , Strohmann Carsten 
Published: November 2008

AbstractA series of (–)‐sparteine‐coordinated lithiosilanes was synthesised and studied by X‐ray structural analysis. All lithiosilanes are monomers in the solid state; yet, increasing sizes of substituents at silicon significantly influences their molecular structures. Due to the given stereochemistry of the dinitrogen (–)‐sparteine ligand, all systems possess stereoinformation. NMR spectroscopic studies were used to obtain deeper insight into the structures of these compounds in solution. Observed coupling between the silicon and lithium atoms as well as the presence of only one signal for each atom in the NMR spectra are indicative of monomeric structures of the lithiosilanes in solution. Additional quantum chemical calculations on one of the examined (–)‐sparteine‐coordinated systems provided very small energy differences between the diastereomers.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthetic and Theoretical Investigations on the Construction of Oxanorbornenes by a Michael Addition and Intramolecular Diels–Alder Furan Reaction
Authors: Dadwal Mamta , Kesharwani Manoj K. , Danayak Vaishalee , Ganguly Bishwajit , Mobin Shaikh M. , Muruganantham Rajendran , Namboothiri Irishi N. N. 
Published: November 2008

AbstractThe conjugate addition of nucleophiles such as allylmercaptan, allyl‐ and homoallylmalonate and diallylamine to β‐furyl enones and acrylate, provides the Michael adducts in good yield. A facile intramolecular Diels–Alder reaction between the unsaturated tether and the furan diene ensues when these adducts are heated in a solvent such as toluene orxylene to afford the cycloadducts in good yield and excellent stereoselectivity in most cases. The structure and stereochemistry of these cycloadducts were confirmed by extensive NMR experiments and X‐ray crystallography. Quantum chemical calculations on the transition state and product geometries suggest that the formation of the cycloadducts, in which the newly formed ring is exo‐fused to the oxanorbornene framework, is favored over the endo‐fused product due to less strain in the former and its transition state.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
The Grignard Reagent Formation Reaction of 2‐Chloro‐1,1,1‐triphenylethane Revisited
Authors: Bickelhaupt Friedrich , Newcomb Martin , DeZutter Christopher B. , de Boer Henk J. R. 
Published: November 2008

AbstractThe reaction of 2‐chloro‐1,1,1‐triphenylethane (1) with magnesium in THF has been reinvestigated. The reaction produced a dark‐red solution and after deuterolysis with D2O, 1,1,1‐triphenylethane (2; 16 %), 2‐D‐1,1,1‐triphenylethane (3; 52 %) and 1,1,2‐triphenylethene (4; 26 %) were isolated. Rate constants for phenyl migration in the 2,2,2‐triphenylethyl radical were measured directly between 23 °C and 55 °C; the reaction is described by log k = 11.2 – 7.5/2.3 RT [kcal/mol] and the rate constant for rearrangement at 20 °C is 4.0 × 105 s–1. The combined results support the intermediate formation of radicals in the reaction of chloride 1 with magnesium. The red colour of the reaction mixture, however, indicates the formation of a carbanionic species, which has not yet been identified. The diffusion model for Grignard formation reactions of Garst et al. is in line with the product distribution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and Stable‐Ion Studies of Regioisomeric Acetylnitropyrenes and Nitropyrenyl Carbinols and GIAO‐DFT Study of Nitro Substituent Effects on α‐Pyrenyl Carbocations
Authors: Laali Kenneth K. , Arrica Maria A. , Okazaki Takao , Bunge Scott D. 
Published: November 2008

AbstractSeveral regioisomeric acetylnitropyrenes were synthesized from isomeric acetylpyrenes by mild protic nitration. Nitration of 1‐acetylpyrene gave the 3‐, 6‐, and 8‐nitro derivatives (with 8‐nitro as the major isomer), from which the corresponding carbinols [NO2‐Py‐CH(OH)CH3; Py = pyrene] were synthesized. Isomeric 4‐acetylnitropyrenes and their corresponding carbinols were synthesized by starting from hexahydropyrene through nitration/aromatization/reduction or aromatization/nitration/reduction sequences. The molecular structures of 4‐acetyl‐3‐nitropyrene and 1‐(6‐nitropyren‐1‐yl)ethanol were established by X‐ray analysis. Tetrahydropyrene was the starting point for the synthesis of isomeric nitro‐2‐acetylpyrenes. Low‐temperature protonation of 1‐acetyl‐8‐nitropyrene, 4‐acetyl‐3‐nitropyrene, and 2‐acetyl‐6‐nitropyrene in FSO3H/SO2ClF or in FSO3H/SbF5 (1:1)/SO2ClF resulted in the formation of onium dications (by C=O and NO2 protonation). Charge delocalization (pyrenium ion character) in the carboxonium ions is strongly influenced by the position of the carboxonium group, with the 4‐acetyl‐3‐nitropyrene dication being the most delocalized. Superacid protonation of 1‐(3‐nitropyren‐4‐yl)ethanol gave a persistent onium dication rather than an α‐pyrenyl carbocation. With all other isolated nitropyrenyl carbinol isomers, low‐temperature protonation (with FSO3H/SO2ClF) led to polymerization within 5 min standing at dry‐ice–acetone temperature. For these cases, nitro substituent effects on the α‐pyrenyl carbocations were gauged by DFT and GIAO‐DFT studies. An interesting relationship between the computed nitro tilt angles and the GIAO‐derived charge delocalization modes was observed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Development of New Pyrrolocoumarin Derivatives with Satisfactory Fluorescent Properties and Notably Large Stokes Shifts
Authors: Chen Lei , Hu Tai‐Shan , Yao Zhu‐Jun 
Published: November 2008

AbstractSmall, organic, fluorescent molecules with large Stokes shifts and long emission wavelengths are ideal dyes for various modern fluorescent imaging technologies such as FRET. In this study, we designed and synthesized a number of new fluorescent molecules on the basic structures of two pyrrolocoumarin skeletons where Fischer's indole synthesis and the Suzuki coupling successfully served as the efficient molecular editing protocols. The examination of the fluorescent properties and further structural optimization of these compounds afforded three new pyrrolocoumarin dyes with notably large Stokes shifts and satisfactory fluorescent properties. Among these, 30 showed a large Stokes shift (113 nm) and intense fluorescence (φ = 0.55, λem = 523 nm), and thus showed great potential in biological imaging studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Desulfurization Mediated by Hypervalent Iodine(III): A Novel Strategy for the Construction of Heterocycles
Authors: Ghosh Harisadhan , Yella Ramesh , Nath Jayashree , Patel Bhisma K. 
Published: November 2008

AbstractThe desulfurization ability of diacetoxyiodobenzene (DIB) has been explored in the preparation of isothiocyanates from the corresponding dithiocarbamate salts. The in situ generated isothiocyanates reacted with o‐phenylenediamine and o‐aminophenol to form monothioureas, which, on treatment with a further equivalent of DIB in one pot, gave benzimidazoles and aminobenzoxazoles, respectively. Aliphatic 1,2‐diamines on reaction with 2 equiv. of isothiocyanate followed by treatment with DIB gave imidazolidenecarbothioamides, whereas the treatment of aromatic 1,2‐diaminebis(thioureas) yielded benzimidazoles with the concurrent formation of isothiocyanate. The driving force for the formation of the latter is the aromatization of the product. The use of DIB makes these methods simpler and more efficient, giving high yields of the desired products in one pot.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A methodology for simulating power system vulnerability to cascading failures in the steady state
Authors: Kumbale Murali , Hardiman Rod , Makarov Yuri 
Published: November 2008

AbstractSimulations of power system conditions and event sequences leading to either local or widespread blackout has acquired increasing importance following wide‐impact network collapses that have occurred over the past several years in North America and Europe. This paper summarizes an analytical framework that has been developed, implemented, and practically used by Southern Company to evaluate system vulnerability to cascading failures using the steady state model. This methodology was first used by Southern Company in 1999. The studies performed at Southern Company have already influenced and motivated certain transmission development projects. Future improvements to the method could include better modeling and sequencing of cascading steps, including time sequence of failures using equipment response time. Significant interest exists in developing preventive methods and procedures and in the application of this technology in the infrastructure security arena. Copyright © 2008 John Wiley & Sons, Ltd.
A Sb‐doped SnP2O7 Solid Proton Conductor for Intermediate Temperature Fuel Cells
Authors: Wu X. , Verma A. , Scott K. 
Published: November 2008

AbstractSb‐doped SnP2O7 were prepared and characterised with XRD, FTIR, SEM and EIS. The preparation parameters were optimised taking into consideration the influence of H3PO4 content in the reactants and PmOn impurities. Conductivities of SnP2O7 with different Sb doping levels were studied from 100 to 300 °C in un‐humidified air. The conductivity of 20 mol‐% Sb‐doped SnP2O7 was greater than 0.1 S cm–1 at 300 °C. The effect of heat treatment was identified as an important factor in the preparation of the proton conductors. The time dependence of the conductivity demonstrated Sb‐doped SnP2O7 as a promising intermediate temperature solid proton conductor.
A Membraneless Direct Borohydride Fuel Cell Using LaNiO3‐Catalysed Cathode
Authors: Ma J. , Liu Y. , Liu Y. , Yan Y. , Zhang P. 
Published: November 2008

AbstractDirect borohydride fuel cell (DBFC) is one of the most exciting energy technologies that solve the hydrogen storage and safety issues by using aqueous solution of KBH4 or NaBH4. Here, we present a membraneless DBFC with perovskite‐type oxide LaNiO3/C‐catalysed cathode. A significant finding from the electrochemical experiments is that it obviously shows that the existence of $ {\rm BH}_4^- $ ions has almost no negative influence on the discharge performances of the LaNiO3‐catalysed cathode. Therefore, the DBFC is designed without using an ion exchange membrane. The maximal power density of 127 mW cm–2 is obtained at 65 °C under atmospheric pressure. A 500 h life test shows that the DBFC has good stability.
Late Alpine tectonics in the Ligurian Alps: constraints from the Tertiary Piedmont Basin conglomerates
Authors: Capponi Giovanni , Crispini Laura , Federico Laura , Piazza Michele , Fabbri Barbara 
Published: November 2008

AbstractThe Tertiary Piedmont Basin (TPB) is a syn‐tectonic Neoalpine–Apennine basin with an upper Eocene–upper Miocene sedimentary succession. It has an inner position with respect to the arcuate belt of the Western and Ligurian Alps, in northwestern Italy. In the area north of Genova, the Scrivia Valley separates two distinct sectors where the TPB basal conglomerates display a differentiated clast provenance: in the western sector conglomerates are fed by the metamorphic units of central Liguria, whereas in the eastern sector most of the conglomerate clasts come from the Antola flysch Unit. Observations on clast lithology demonstrate that the transition between the two types of conglomerates is abrupt and roughly coincides with the Scrivia River Valley. An explanation of the different clast provenance as due to a progressive deepening of the erosional level appears to be possible in the eastern sector, but it is not feasible in the western sector, where the flysch units appear to have been protected from erosion. We propose that the northwards thrusting of the Ligurian Alps metamorphic units onto the Antola flysch units, made the latter not available to erosion and led the Scrivia Fault and other equivalent tectonic lineaments to act as tear faults.Field data suggest that the Tertiary geodynamics of the Ligurian Alps was dominated by the Corsica–Sardinia anticlockwise rotation, that caused the northwards backthrusting of the Ligurian Alps, accommodated by a complex strike‐slip fault system, that segmented the TPB, affecting the sedimentation and the clast provenance of the conglomerates. Copyright © 2008 John Wiley & Sons, Ltd.
Synthetic polymeric substrates as potent pro‐oxidant versus anti‐oxidant regulators of cytoskeletal remodeling and cell apoptosis
Authors: Sung Hak‐Joon , Chandra Prafulla , Treiser Matthew D. , Liu Er , Iovine Carmine P. , Moghe Prabhas V. , Kohn Joachim 
Published: November 2008

AbstractThe role of reactive oxygen species (ROS)‐mediated cell signal transduction pathways emanating from engineered cell substrates remains unclear. To elucidate the role, polymers derived from the amino acid L‐tyrosine were used as synthetic matrix substrates. Variations in their chemical properties were created by co‐polymerizing hydrophobic L‐tyrosine derivatives with uncharged hydrophilic poly(ethylene glycol) (PEG, Mw = 1,000 Da), and negatively charged desaminotyrosyl‐tyrosine (DT). These substrates were characterized for their intrinsic ability to generate ROS, as well as their ability to elicit Saos‐2 cell responses in terms of intracellular ROS production, actin remodeling, and apoptosis. PEG‐containing substrates induced both exogenous and intracellular ROS production, whereas the charged substrates reduced production of both types, indicating a coupling of exogenous ROS generation and intracellular ROS production. Furthermore, PEG‐mediated ROS induction caused nuclear translocation of glyceraldehyde‐3‐phosphate dehydrogenase and an increase in caspase‐3 activity, confirming a link with apoptosis. PEG‐rich pro‐oxidant substrates caused cytoskeletal actin remodeling through β‐actin cleavage by caspase‐3 into fractins. The fractins co‐localized to the mitochondria and reduced the mitochondrial membrane potential. The remnant cytosolic β‐actin was polymerized and condensed, events consistent with apoptotic cell shrinkage. The cytoskeletal remodeling was integral to the further augmentation of intracellular ROS production. Conversely, the anti‐oxidant DT‐containing charged substrates suppressed the entire cascade of apoptotic progression. We demonstrate that ROS activity serves an important role in “outside‐in” signaling for cells grown on substrates: the ROS activity couples exogenous stress, driven by substrate composition, to changes in intracellular signaling. This signaling causes cell apoptosis, which is mediated by actin remodeling. J. Cell. Physiol. 218: 549–557, 2009. © 2008 Wiley‐Liss, Inc.
Skeletal muscle contractions uncoupled from gravitational loading directly increase cortical bone blood flow rates in vivo
Authors: Caulkins Carrie , Ebramzadeh Edward , Winet Howard 
Published: November 2008

AbstractThe direct and indirect effects of muscle contraction on bone microcirculation and fluid flow are neither well documented nor explained. However, skeletal muscle contractions may affect the acquisition and maintenance of bone via stimulation of bone circulatory and interstitial fluid flow parameters. The purposes of this study were to assess the effects of transcutaneous electrical neuromuscular stimulation (TENS)‐induced muscle contractions on cortical bone blood flow and bone mineral content, and to demonstrate that alterations in blood flow could occur independently of mechanical loading and systemic circulatory mechanisms. Bone chamber implants were used in a rabbit model to observe real‐time blood flow rates and TENS‐induced muscle contractions. Video recording of fluorescent microspheres injected into the blood circulation was used to calculate changes in cortical blood flow rates. TENS‐induced repetitive muscle contractions uncoupled from mechanical loading instantaneously increased cortical microcirculatory flow, directly increased bone blood flow rates by 130%, and significantly increased bone mineral content over 7 weeks. Heart rates and blood pressure did not significantly increase due to TENS treatment. Our findings suggest that muscle contraction therapies have potential clinical applications for improving blood flow to cortical bone in the appendicular skeleton. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 651–656, 2009
Poly(amidoamine) Conjugates Containing Doxorubicin Bound via an Acid‐Sensitive Linker
Authors: Lavignac Nathalie , Nicholls Johanna L. , Ferruti Paolo , Duncan Ruth 
Published: November 2008

AbstractPoly(amidoamine)s with amino pendant groups were prepared by hydrogen‐transfer polyaddition of primary and secondary amines to bis‐acrylamines. Dansyl cadaverine (DC) doxorubicin (Dox) were bound to the polymers via acis‐aconityl spacer to give conjugates containing 3 µg of DC per mg of polymer and 28 to 35 µg of Dox per mg of polymer. Release of DC and Dox at physiological and acidic pH varied from 0 to 35% over 48 h and was pH dependent. Although the ISA1Dox conjugate (IC50 = 6 µg Dox · mL−1) presented similar toxicity as the parent polymer without Dox, ISA23Dox showed increased toxicity (IC50 = 10 µg Dox · mL−1). These results suggest that ISA23Dox is able to release biologically active Doxin vitroand that this conjugate might be suitable for further development.magnified image
Molecular Structure of Physiologically‐Responsive Hydrogels Controls Diffusive Behavior
Authors: Carr Daniel A. , Peppas Nicholas A. 
Published: November 2008

AbstractPolymeric networks and the ensuing hydrogels of MAA and NVP were successfully synthesized using a UV‐initiated free radical polymerization and characterized to assess their applicability as carriers for directed drug delivery. FT‐IR spectroscopy revealed shifts in peak absorbances that indicated the presence of hydrogen bonding complexes between functional groups, while SEM imaging showed that the different comonomers affect the surface morphology of the microparticles. Dynamic pH swelling studies demonstrated the pH responsiveness of the carriers in gastric and intestinal conditions and revealed that systems containing higher concentrations of MAA experienced the highest degree of hydrogen bonding complexation in gastric conditions. The presence of NVP in the systems enhanced swelling. Equilibrium swelling studies revealed that the mesh size was sufficiently large to allow drug diffusion across the networks.magnified image
Effect of Nanoplatelets on the Rheological Behavior of Epoxy Monomers
Authors: Sun Luyi , Boo Woong‐Jae , Liu Jia , Clearfield Abraham , Sue Hung‐Jue , Verghese Nikhil E. , Pham Ha Q. , Bicerano Jozef 
Published: November 2008

AbstractThe effect of nanoplatelets on the rheological behavior of epoxy monomers with variations in nanoplatelet exfoliation level and aspect ratio was investigated. The results show that the presence of exfoliated nanoplatelets in epoxy can significantly influence viscosity and lead to shear‐thinning phenomena, especially when the aspect ratio of the nanoplatelets is high. By employing the Krieger‐Dougherty model, the effectiveness of nanoplatelets in altering epoxy rheological behavior was quantitatively described and compared with experimental findings. Possible physical reasons for the observed rheological behaviors are discussed. The implication of the present study for polymer nanocomposites processing is also addressed.magnified image
Synthesis of Crosslinked Sulfonated Poly(phenylene sulfide sulfone nitrile) for Direct Methanol Fuel Cell Applications
Authors: Phu Duong Sang , Lee Chang Hyun , Park Chi Hoon , Lee So Young , Lee Young Moo 
Published: November 2008

AbstractWith a view towards direct methanol fuel cell applications, novel sulfonated poly(phenylene sulfide sulfone nitrile) (sPPSSfN) has been prepared and subsequently crosslinked by a Friedel‐Craft reaction using 4,4′‐oxybis(benzoic acid) as a crosslinker to achieve lower water swelling and lower methanol permeability. The dimensional change of SPPSSfN40 is 43.7% in 90 °C liquid water but that of the crosslinked membrane, XsPPSSfN40, is 23.3% while maintaining proton conductivity at 0.22 S · cm−1. These results show that the Friedel‐Craft crosslinking of the novel sPPSSfN membrane effectively reduces water uptake and the degree of swelling while improving the dimensional stability and maintaining high proton conductivity.magnified image