bluuebunny/crossref_metadata_2025 huggingface dataset:
Grid Convergence Study in a Simulation of LAPD Turbulence
Authors: Friedman B. , Umansky M.V. , Carter T.A.
Published: June 2012

Grid convergence of plasma drift turbulence simulations in the Large Plasma Device is studied. When first order upwind advection schemes are used, numerical finite difference diffusion errors cause turbulence statistics, especially saturation levels to vary when grid spacing is changed. The significance and magnitude of the variation is explored, and it is found that use of very fine meshes or higher order advection schemes combined with artificial diffusion and viscosity can lead to grid convergence, while maintaining experimentally consistent saturation levels. It is also found that the details of dissipation range dynamics, such as the level of diffusion, have a significant impact on driven range dynamics due to the lack of a large inertial range in the simulations (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of Radiation Transport in Fluctuating Edge Plasmas: A Statistical Approach
Authors: Rosato J. , Mekkaoui A. , Marandet Y. , Reiter D. , Kotov V. , Capes H. , Godbert‐Mouret L. , Koubiti M. , Stamm R.
Published: June 2012

The radiation due to atomic lines in the tokamak edge and divertor can be strongly coupled to the plasma dynamics. Self‐consistent (charged particle ‐ atom ‐ photon) simulations carried out for ITER conditions with the transport code B2‐EIRENE have indicated modifications of the effective ionization rate induced by photon absorption effects. Up to now, all of the investigations done so far were made assuming a plasma background whose typical spatial variation scales are much larger than the radiation transport scale. In this paper, we examine the validity of this approximation within an effective transport model, relying on a statistical parameterization of the turbulent fluctuations. The model is inspired from the quasilinear theory used for plasma turbulence and assumes a small ratio lturb/lmfp between the turbulence correlation length and the photon mean free path. We apply the model to calculations of the penetration of a radiation pencil in an optically thick turbulent plasma. The validity of this model for intermediate lturb/lmfp is next discussed through comparison to a “model‐coefficient” approach, widely used in problems involving linear stochastic differential equations and suitable for arbitrary turbulence correlation length (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamic Models for Plasma‐Wall Interactions
Authors: Pigarov A.Yu. , Krstic P. , Krasheninnikov S.I. , Doerner R. , Rognlien T.D.
Published: June 2012

In theory and modeling of plasma‐wall interactions, very different spatial and temporal scales need to be resolved. Hierarchy of material models (e.g. macroscopic transport, Kinetic Monte Carlo, Molecular Dynamics, and quantum models) used in fusion applications is reviewed and a way of their integration is highlighted. Physics background, theory and applications of macroscopic transport models, which are the main focus of the paper, are thoroughly discussed. The results on self‐consistent macroscopic modeling of major physics phenomena, e.g. hydrogen recycling, retention, chemistry, chemical sputtering, and radiation enhanced sublimation for fusion related materials are presented. An example of coupled plasma and material transport simulations is given. The results on Molecular Dynamics modeling of deuterium irradiation of carbon leading to formation of supersaturated surfaces and chemical sputtering are presented (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conditions for the Release of a Metallic Dust Particle from a Plasma‐Facing Wall
Authors: Ueno M. , Ohno N. , Tomita Y. , Kawamura G.
Published: June 2012

The conditions for the release of a dust particle from a plasma‐facing wall into a fusion plasma, which is the starting point of the dust transport process, is studied theoretically. The analytical model in this study is for a spherical conducting dust particle on a flat plasma‐facing wall. The forces on the dust particle considered in this model are the electrostatic force, ion friction force and gravitational force. The electrostatic force and ion friction force depend on Ti/Te, where Ti and Te are ion and electron temperatures. A maximum Ti/Te is required for the release of a dust particle from the wall. The gravitational force is important in the case of a dust particle on a horizontal wall. In this case, the release condition is determined by the quantity Rd/nseTe, as well as the temperature ratio, where Rd, nse are the dust radius and the electron density at the sheath entrance, respectively (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development and Benchmarking of a New Kinetic Code for Plasma Periphery (KIPP)
Authors: Chankin A.V. , Coster D.P. , Meisl G.
Published: June 2012

A new kinetic code is presently being developed at IPP Garching to describe parallel (along magnetic field lines) plasma transport in the SOL and divertor of tokamaks. The development of the code is aimed at replacing parallel transport equations used in the present day fluid codes such as SOLPS(B2), EDGE2D, UEDGE. The code is based on the continuum discretisation scheme for the Fokker‐Planck equation for parallel plasma transport. In the physical space (along B‐lines) the fine spatial structure on the scale of the Debye length is not resolved, instead, plasma quasi‐neutrality on a much longer scale, controlled by the parallel electron momentum balance equation, is assumed. At the interface with a material surface, the logical sheath condition is used. The code initially is 1D2V, with parallel and gyro‐averaged perpendicular velocities being independent velocity variables. In the future, extension of the kinetic treatment on ions, and extension of the code dimensionality to 2D2V to cover also radial (across magnetic field lines) dimension is envisaged. Details of the code, together with its benchmarking by comparing code results with analytical theory in the limit of highly collisional plasmas, are presented in the paper (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Test Simulations of the Kinetic Model for the Thermal Force based on the Monte Carlo Binary Collision Model
Authors: Homma Y. , Hatayama A.
Published: June 2012

We have developed a numerical model of the thermal force based on the Monte Carlo Binary Collision model, where a distorted Maxwellian velocity distribution is used for a background plasma. Our numerical model can be applied to transport simulation of test ions in a high‐collisionality background plasma without magnetic field. In this study, by a series of systematic test simulations, we have confirmed the consistency of our numerical modeling approach with the form of the thermal force analytically derived from the distorted Maxwllian velocity distribution. The test of our model has been done with respect to its dependence on parameters such as: (1) direction of the background temperature gradient, (2) test particle mass, (3) background plasma ion species, and (4) background flow velocity (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heat Flux Dependence of Ambipolar Potential and Plasma Profile in a Long Mean‐Free‐Path Plasma Along Non‐Uniform Open Magnetic Field Lines
Authors: Guo Z. , Tang X.‐Z.
Published: June 2012

Parallel transport along an open magnetic field line produces and sustains temperature anisotropy for a long mean‐free‐path plasma. The parallel variation of ambipolar potential (Φ) and plasma profiles such as density (n), parallel and perpendicular temperature (T‖ and T⊥), and parallel flow (u), is found to be critically dependent on the two distinct components of the parallel heat flux, qn and qs. Both their profile (qn/B and qs/B2) and the upstream values of the ratio of the conductive and convective thermal flux (qn/nuT‖ and qs/nuT⊥) provide the controlling physics, in addition to B modulation (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cytometric quantification of singlet oxygen in the human malaria parasitePlasmodium falciparum
Authors: Butzloff Sabine , Groves Matthew R. , Wrenger Carsten , Müller Ingrid B.
Published: June 2012

The malaria parasitePlasmodium falciparumproliferates within human erythrocytes and is thereby exposed to a variety of reactive oxygen species (ROS) such as hydrogen peroxide, hydroxyl radical, superoxide anion, and highly reactive singlet oxygen (1O2). While most ROS are already well studied in the malaria parasite, singlet oxygen has been neglected to date. In this study we visualized the generation of1O2by live cell fluorescence microscopy using 3‐(p‐aminophenyl) fluorescein as an indicator dye. While1O2is found restrictively in the parasite, its amount varies during erythrocytic schizogony. Since the photosensitizer cercosporin generates defined amounts of1O2we have established a new cytometric method that allows the stage specific quantification of1O2. Therefore, the parasites were first classified into three main stages according to their respective pixel‐area of 200–600 pixels for rings, 700–1,200 pixels for trophozoites and 1,400–2,500 pixels for schizonts. Interestingly the highest mean concentration of endogenous1O2of 0.34 nM is found in the trophozoites stage, followed by 0.20 nM (ring stage) and 0.10 nM (schizont stage) suggesting that1O2derives predominantly from the digestion of hemoglobin. © 2012 International Society for Advancement of Cytometry
Design support system for coloring illustrations by using the colors preferred by a user as determined from the hue patterns of illustrations prepared by that user
Authors: Fukai Hironobu , Mitsukura Yasue
Published: June 2012

We propose a new design support system that can color illustrations according to a person's color preferences that are determined on the basis of the color patterns used by the same person in his previous work. Recently, many design tools for promoting free design have been developed. However, preferences for various colors differ depending on individual taste. Therefore, a system that can automatically color various designs on the basis of human preference is required. In this study, we propose an automatic modeling system that can be used to model illustrations. To verify the effectiveness of the proposed system, we simulate a coloring design experiment to determine the color patterns preferred by test subjects by using various design data. By using the design data, we determine each subject's preferred color pattern, and send feedback on these individual color patterns in the proposed system. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(1): 19–27, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21283
A new CST method for Carrier‐type dynamic strain amplifier with C component on four legs of bridge
Authors: Kubodera Shinji , Tanzawa Tsutomu , Kiyohiro Noriaki
Published: June 2012

Carrier‐type dynamic strain amplifiers are frequently used for stress measurement with strain gages. That is because the carrier‐type dynamic strain amplifier can perform high precision measurement since it is highly resistant to external noise or power noise in the field. The strain gage has little effect on the specimen being measured since it is small and light. However, it is required to connect the input cable from the target strain gage to the amplifier. When using the carrier‐type dynamic amplifier, distributed capacitance due to the input cable greatly affects zero point variation. Changes in the distributed capacitance degrade the stability of the dynamic strain amplifier.

We present a new Dual Feedback CST (Capacitance Self Tracing) method that detects, self‐tracks, and eliminates the capacitive component generated in any leg of the measuring bridge. The zero‐point variation is not affected by the carrier frequency and resistance value and can be canceled if the bridge is balanced in the CST method. We conducted experiments with strain gage resistances of 120 and 350 ohms and carrier frequencies of 5, 12, and 28 kHz and verified the zero‐point stability. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(1): 11–18, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22294
Indium‐Mediated Aza‐Henry Reaction of Imines: Access to 2‐Nitroamines
Authors: Soengas Raquel G. , Silva Sandrina , Estévez Amalia M. , Estévez Juan C. , Estévez Ramón J. , Rodríguez‐Solla Humberto
Published: June 2012

A new method has been developed to obtain 2‐nitroamines by an indium‐promoted reaction of bromonitromethane with a variety of imines. On the strength of these results, the reaction was also performed with 2‐bromo‐2‐nitropropanes to afford 2,2‐dialkyl‐2‐nitroamines. Moreover, the indium‐mediated reaction of 1‐bromo‐1‐nitroethane and imines afforded 1‐methyl‐2‐nitroamines with remarkably high anti selectivity. The use of chiral sugar‐derived imines furnished the corresponding 2‐nitroamines with excellent stereoselectivity.
Silica‐Catalysed and Highly Stereoselective Convergent and Nonconvergent Rearrangements of Menthone Enol Acetate Epoxides: Easy Access to the Four α‐Hydroxymenthone Stereoisomers
Authors: Tranchimand Sylvain , Faure Bruno , Naubron Jean‐Valère , Alphand Véronique , Archelas Alain , Iacazio Gilles
Published: June 2012

During a program dedicated to the biocatalytic access of structurally useful α‐hydroxy ketones, we made the unexpected observation that epoxy enol acetates derived from (+)‐ and (–)‐menthone stereoselectively rearranged on exposure to silica through a diastereoselective process, providing easy access to the complete set of α‐hydroxymenthone stereoisomers. The absolute configurations of the four stereoisomers were unambiguously established by IR‐VCD and X‐ray diffraction, thus clarifying some literature discrepancy. Two of the four stereoisomers could also be obtained through astereoconvergent process, thus avoiding the inherent 50 % yield limitations of such diastereoselective reactions. A solvent‐free version allowing an extremely rapid reaction (< 2 h) is also described. Finally, the observed diastereoselection was investigated by DFT calculations.
Electrochemical Examination of Copper(II) Complexes with Octaazamacrocyclic Ligand and Heterocyclic Dithiocarbamate
Authors: Petković B. , Stevanović S. , Budimir M. , Sovilj S. P. , Jovanović V. M.
Published: June 2012

Mixed ligand dinuclear copper(II) complexes of the general formula [Cu2(Rdtc)tpmc)](ClO4)3 with octaazamacrocyclic ligand tpmc and four different heterocyclic dithiocarbamate ligands Rdtc−, as well as the complexes [Cu2(tpmc)](ClO4)4 and [Cu(tpmc)](ClO4)2⋅2H2O were studied in aqueous NaClO4 and HClO4 solutions by cyclic voltammetry on glassy carbon electrode. The electrochemical properties of the ligands and Cu(II) complexes were correlated with their electronic structure. Conductometric experiments showed different stoichiometry in complexation of tpmc with Cu2+ ions and transport of ions in acetonitrile and in aqueous media. These studies clarified the application of this macrocyclic ligand as ionophore in a PVC membrane copper(II) selective electrode and contributed elucidation of its sensor properties.
Preparation and application of hydrophobic hybrid monolithic columns containing polyhedral oligomeric silsesquioxanes for capillary electrochromatography
Authors: Ou Junjie , Zhang Zhenbin , Lin Hui , Dong Jing , Wu Minghuo , Zou* Hanfa
Published: June 2012

Hydrophobic organic–inorganic hybrid monolithic columns were synthesized via thermally initiated free radical polymerization with the confines of 75 μm id capillary using a polyhedral oligomeric silsesquioxane (POSS) reagent containing eight or more methacrylate groups as the crosslinker. Three organic functional monomers, butyl methacrylate (BuMA), lauryl methacrylate (LMA) and methacrylic acid (MAA), were selected and copolymerized with the POSS in the presence of 1‐propanol and 1,4‐butanediol to prepare the poly(POSS‐co‐BuMA), poly(POSS‐co‐LMA), and poly(POSS‐co‐MAA) monoliths, respectively. The 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) was copolymerized as ionizable monomer into the poly(POSS‐co‐BuMA) and poly(POSS‐co‐LMA) for the generation of EOF in capillary electrochromatography (CEC). A hybrid poly(POSS‐co‐LMA‐co‐MAA) monolith was also similarly prepared by copolymerizing ternary monomers of POSS, LMA, and MAA, and compared with poly(POSS‐co‐BuMA), poly(POSS‐co‐LMA), and poly(POSS‐co‐MAA) monoliths. The resulting four kinds of POSS‐contained hybrid monoliths exhibited good permeability and mechanical stability. Their column efficiencies were evaluated by the separation of alkylbenzene homologues and polar compounds in CEC. The results indicated that the highest efficiencies of 194 100 and 102 100 theoretical plates per meter for thiourea and benzene were obtained on the poly(POSS‐co‐LMA‐co‐MAA) monolith. Additionally, the poly(POSS‐co‐LMA‐co‐MAA) monolith exhibited better selectivity for separation of polar compounds than those of other hybrid monoliths.
Molecularly imprinted SPE and MEKC with in‐capillary sample preconcentration for the determination of digoxin in human urine
Authors: Guijarro‐Díez Miguel , Paniagua Gema , Fernández Pilar , Crego Antonio Luis , Marina María Luisa
Published: June 2012

Molecularly imprinted solid‐phase extraction (MISPE) combined with MEKC was used for clean‐up, preconcentration and determination of digoxin in the presence of its aglycon digoxin (digoxigenin) in human urine samples. In addition, the use of an in‐capillary sample concentration electrophoretic technique by sweeping was investigated to enhance the concentration sensitivity in MEKC. The highly selective, fast and effective sample pretreatment by MISPE along with the preconcentration by sweeping could overcome the low sensitivity of the highly efficient capillary electrophoresis separation with UV detection. The optimization of the variables affecting the separation as well as MISPE conditions procedure was carried out to select the best conditions of selectivity and sensitivity to determine digoxin at low concentration levels in urine. To demonstrate the suitability of the developed method several analytical characteristics (selectivity, linearity, accuracy, precision, and LOD) were evaluated. Satisfactory results were obtained in terms of linearity (r > 0.99), recovery (95.4–96.5% with RSD from 1.3% to 2.6%), precision (RSD from 0.3% to 1.7% for migration times and from 2.1% to 7.3% for corrected peak areas), and sensitivity (LODs of 6 μg/L with 5 mL of sample or 1.2 μg/L with 25 mL). The proposed MISPE‐MEKC method was satisfactorily applied to the analysis of spiked human urine samples achieving a concentration factor up to 7500‐fold.
Sample stacking by field‐amplified sample injection and sweeping for simultaneous analysis of acidic and basic components in clinic application
Authors: Wei Shao‐Yun , Wang Li‐Fang , Yang Yuan‐Han , Yeh Hsin‐Hua , Chen Yi‐Chin , Chen Su‐Hwei
Published: June 2012

In this study, online sample concentration method, which coupled field‐amplified sample injection (FASI) and sweeping technology with micellar electrokinetic chromatography (MEKC), was used to detect and analyze acidic and basic components in a single run. In order to concentrate the acidic and basic components simultaneously in a single run sweeping step, a combination of successive anion‐ and cation‐selective injections were used. Before sample loading, a rinse buffer containing 50 mM Tris buffer (pH 3) with 41% MeOH and 0.1% polyethylene oxide (PEO) was injected in order to suppress the electroosmotic flow (EOF). Sample loading of anionic components was achieved by electrokinetic injection at a negative voltage of −2.5 kV for 80 s, and then the cationic components were injected at a positive voltage of +5 kV for 120 s. Finally, sweeping with SDS micelles from the separation buffer (25 mM Tris buffer with 60 mM SDS, pH 3) was performed at a negative voltage of −20 kV. This capillary electrophoretic methodology was applied to the quantification of acidic and basic drugs in commercial tablets and in plasma samples. The precision and accuracy of the proposed method at different concentrations ranging from high, medium, to low were evaluated on spiked plasma samples. The intra and interday precision and accuracy values at three concentrations were all below 6.1%. The method was also successfully applied to monitor the tested drugs in the plasma of nine elderly cardiovascular and/or Alzheimer's disease patients after oral administration of the commercial products.
Capillary electrophoresis‐mass spectrometry methods for tryptic peptide mapping of therapeutic antibodies
Authors: Whitmore Colin D. , Gennaro Lynn A.
Published: June 2012

Tryptic peptide mapping is routinely used in the biotech industry to confirm primary sequence, cell line stability, and to analyze posttranslational modifications. Peptide analysis is generally done by reverse phase liquid chromatography with UV or mass spectrometric detection. This method provides excellent resolution and sequence coverage. However, traditional methods are slow, and generally cannot detect small, hydrophilic peptides due to coelution with the column void volume. In this work, complementary CE‐MS peptide analysis methods have been developed. The analyses are performed on a traditional CE‐MS instrument with a sheath interface, and also on a novel sheathless interface that promises improved resolution and limit of detection. The methods were performed on a tryptic digest of a therapeutic monoclonal antibody for which LC‐MS detects 97% sequence coverage. The 3% not covered consists of 11 peptides containing three amino acids or fewer, including two in the critical complementarity binding domain. Without further processing, the same tryptic digest was analyzed by CE‐MS. Separation and detection of the 11 small peptides was achieved on CE‐MS systems with both interfaces. The sheathless system produced better peak capacity and gave mass spectra with significantly less noise, while the sheath system proved to have better repeatability.
Smart portable electrophoresis instrument based on multipurpose microfluidic chips with electrochemical detection
Authors: Fernández‐la‐Villa Ana , Sánchez‐Barragán Dámaso , Pozo‐Ayuso Diego F. , Castaño‐Álvarez Mario
Published: June 2012

A second generation of a battery‐powered portable electrophoresis instrument for the use of ME with electrochemical detection was developed. As the first‐generation, the main unit of the instrument (150 mm × 165 mm × 95 mm) consists of four‐outputs high‐voltage power supply (HVPS) with maximum voltage of 3 KV and acquisition system (bipotentiostat) containing 2‐channels for dual electrochemical detection. A new reusable microfluidic platform was designed in order to incorporate the microchips with the portable instrument. In this case, the platform is integrated to the main unit of the instrument so that it is not necessary to have any external cable for the interconnection of both parts, making the use of the complete system easier. The new platform contains all the electrical connections for the HVPS and bipotentiostat, as well as fluidic ports for driving the solutions. The microfluidic electrophoresis instrument is controlled by means of a user‐friendly interface from a computer. The possibility of wireless connection (Bluetooth®) allows the use of the instrument without any external cable improving the portability. Therefore, the second generation brings a more compact and integrated electrophoresis instrument for “in situ” applications using microfluidic chips in an easy way. The performance of the electrophoresis system was initially evaluated using single‐ and dual‐channel SU‐8/Pyrex microchips with different models of integrated electrodes including microelectrodes and interdigitated arrays. The method was tested in different analytical applications such as separation of neurotransmitters, chlorophenols, purine derivatives, vitamins, polyphenolic acids, and flavones.
Life cycle assessment of energy generation of biogas fed combined heat and power plants: Environmental impact of different agricultural substrates
Authors: Lansche Jens , Müller Joachim
Published: June 2012

The utilization of agricultural biomass for anaerobic digestion is increasing in Germany since the first version of the Renewable Energies Sources Act (EEG) in 2000. Main products of this conversion process are biogas and digestate, whereby the biogas is mainly used for generation of heat and electricity in combined heat and power plants (CHP). This study investigated the potential environmental impact of anaerobic digestion processes with different agricultural substrates by the life cycle assessment (LCA) method. It focuses on liquid manure and energy crops as feedstock on the one hand and a comparison of four virtual model plants on the other hand. Besides global warming potential (GWP), the impact categories eutrophication potential (EP) and acidification potential (AP) are presented in this work. The results show that greenhouse gas emissions can be reduced with anaerobic digestion of liquid manure as well as energy crops, particularly when digestate storage tanks are gas‐tight. When energy crops are fermented together with liquid manure, the biggest credit for the avoidance of greenhouse gas emissions was given for the generation of electricity. The results differ from those of GWP when looking at the AP and the EP. These impact categories show similar results with a reduction of emissions for liquid manure in mono‐digestion but increasing emissions for digestion of energy crops together with 0–35% liquid manure.
Statistical problems in the probabilistic prediction of climate change
Authors: Stephenson David B. , Collins Matthew , Rougier Jonathan C. , Chandler Richard E.
Published: June 2012

Future climate change projections are constructed from simulated numerical output from a small set of global climate models—samples of opportunity known as multi‐model ensembles. Climate models do not produce probabilities, nor are they perfect representations of the real climate, and there are complex inter‐relationships due to shared model features. This creates interesting statistical challenges for making inference about the real climate.

These issues were the focus of discussions at an Isaac Newton Institute workshop on probabilistic prediction of climate change held at the University of Exeter on 20–23 September 2010. This article presents a summary of the issues discussed between the statisticians, mathematicians, and climate scientists present at the workshop. In addition, we also report the discussion that took place on how to define the concept of climate. Copyright © 2012 John Wiley & Sons, Ltd.
PANEL PROBIT WITH FLEXIBLE CORRELATED EFFECTS: QUANTIFYING TECHNOLOGY SPILLOVERS IN THE PRESENCE OF LATENT HETEROGENEITY
Authors: Burda Martin , Harding Matthew
Published: June 2012

In this paper, we introduce a Bayesian panel probit model with two flexible latent effects: first, unobserved individual heterogeneity that is allowed to vary in the population according to a nonparametric distribution; and second, a latent serially correlated common error component. In doing so, we extend the approach developed in Albert and Chib (Journal of the American Statistical Association 1993; 88: 669–679; in Bayesian Biostatistics, Berry DA, Stangl DK (eds), Marcel Dekker: New York, 1996), and in Chib and Carlin (Statistics and Computing 1999; 9: 17–26) by releasing restrictive parametric assumptions on the latent individual effect and eliminating potential spurious state dependence with latent time effects. The model is found to outperform more traditional approaches in an extensive series of Monte Carlo simulations. We then apply the model to the estimation of a patent equation using firm‐level data on research and development (R&D). We find a strong effect of technology spillovers on R&D but little evidence of product market spillovers, consistent with economic theory. The distribution of latent firm effects is found to have a multimodal structure featuring within‐industry firm clustering. Copyright © 2012 John Wiley & Sons, Ltd.
Early pathogenesis in the adult‐onset neurodegenerative disease amyotrophic lateral sclerosis
Authors: van Zundert Brigitte , Izaurieta Pamela , Fritz Elsa , Alvarez Francisco J.
Published: June 2012

Amyotrophic lateral sclerosis (ALS) is a devastating paralytic disorder caused by dysfunction and degeneration of motor neurons starting in adulthood. Most of our knowledge about the pathophysiological mechanisms of ALS comes from transgenic mice models that emulate a subgroup of familial ALS cases (FALS), with mutations in the gene encoding superoxide dismutase (SOD1). In the more than 15 years since these mice were generated, a large number of abnormal cellular mechanisms underlying motor neuron degeneration have been identified, but to date this effort has led to few improvements in therapy, and no cure. Here, we consider that this surfeit of mechanisms is best interpreted by current insights that suggest a very early initiation of pathology in motor neurons, followed by a diversity of secondary cascades and compensatory mechanisms that mask symptoms for decades, until trauma and/or aging overloads their protective function. This view thus posits that adult‐onset ALS is the consequence of processes initiated during early development. In fact, motor neurons in neonatal mutant SOD mice display important alterations in their intrinsic electrical properties, synaptic inputs and morphology that are accompanied by subtle behavioral abnormalities. We consider evidence that human mutant SOD1 protein in neonatal hSOD1G93A mice instigates motor neuron degeneration by increasing persistent sodium currents and excitability, in turn altering synaptic circuits that control excessive motor neuron firing and leads to excitotoxicity. We also discuss how therapies that are aimed at suppressing abnormal neuronal activity might effectively mitigate or prevent the onset of irreversible neuronal damage in adulthood. J. Cell. Biochem. 113: 3301–3312, 2012. © 2012 Wiley Periodicals, Inc.
Immobilization of commercial hydrolytic enzymes on poly (acrylonitrile) nanofibers for anti‐biofilm activity
Authors: du Plessis Danielle Marguerite , Botes Marelize , Dicks Leon Milner Theodore , Cloete Thomas Eugene
Published: June 2012

BACKGROUND: Chemical methods used to control biofilm formation in filtration systems are not always effective. Two commercially available proteases and an amylase were immobilized onto polymer nanofibers that are used in the production of filtration membranes.

RESULTS: The enzymes were immobilized onto poly acrylonitrile nanofibers that were chemically activated by imidoesterification to allow the covalent immobilization of enzymes. The immobilized enzymes retained above 80% of the specific activity of the free enzymes. For each of the immobilized enzymes, just below 30% of initial activity was retained after 10 repeated cycles of use. No biofilm formation was observed on nanofibers that were coated with the enzymes, where biofilms formed on non‐coated nanofibers.

CONCLUSION: When considering the combined advantages of this effective immobilization process, the robustness of the enzymes used in this study, and the results of this study indicating activity against biofilms, a valuable addition has been made to filtration membrane technology. © 2012 Society of Chemical Industry
Cushing's syndrome
Authors: Hatipoglu Betul A.
Published: June 2012

Cushing's syndrome (CS) results from prolonged exposure to elevated endogenous cortisol. Majority of cases are caused by ACTH, pituitary, or ectopic origin. Primary adrenal hypersecretion is 15–20% caused by adenomas, carcinomas (ACC), and rarely by nodular adrenocortical disease. CS presents with all typical features. Commonly recommended initial testing are urinary free cortisol, late‐night salivary cortisol, and 1‐mg overnight dexamethasone suppression test (DST). Imaging is the key to diagnosis. CS continues to pose diagnostic and therapeutic challenges; life‐long follow‐up is mandatory. J. Surg. Oncol. 2012; 106:565–571. © 2012 Wiley Periodicals, Inc.
A New VNS Metaheuristic Using MADS as a Local Optimizer
Authors: Zegal Walid , Essaddam Naceur , Brimberg Jack
Published: June 2012

We propose a new hybrid metaheuristic VNSMADS that is an implementation of the Variable Neighbourhood Search (VNS) algorithm with the Mesh Adaptive Direct Search (MADS) as the local search. Because MADS is a Derivative‐Free Optimization method, the targeted problems may be non‐smooth on black box functions possessing several local optima. Constraints other than bounds on the variables are not considered. VNSMADS is applied on a real‐world problem from Finance: the portfolio selection problem using the investor preferences. Numerical results show the efficiency of our approach. Copyright © 2012 John Wiley & Sons, Ltd.
Epoxy‐amine based thermoresponsive networks designed by Diels–Alder reactions
Authors: Marref Mohamed , Mignard Nathalie , Jegat Corinne , Taha Mohamed , Belbachir Mohamed , Meghabar Rachid
Published: June 2012

The synthesis of Diels–Alder (DA) adducts from stoichiometric quantities of a new multi‐maleimide dienophile and epoxy‐amine type oligomers bearing furan group units on their side chains was investigated. Precursors of the DA reaction were first synthesized and their functionalities were determined by 1H NMR and gel permeation chromatography/SEC analysis. TGA and DSC were used to characterize their thermal properties. In this study, the effect of the multi‐furan diene functionality on the network density was analyzed. Rheological analysis was used to highlight the thermal reversibility of the DA reaction and to calculate the average molar weight between crosslinks. The results showed that network density could be regulated or modulated by varying the functionality of the diene. Copyright © 2012 Society of Chemical Industry
Effect of crystallization on microstructure and mechanical properties of poly[(ethylene oxide)‐block‐(amide‐12)]‐toughened poly(lactic acid) blend
Authors: Han Lijing , Han Changyu , Dong Lisong
Published: June 2012

The effect of crystallization on the microstructure and mechanical properties of a poly[(ethylene oxide)‐block‐(amide‐12)] (PEBA)‐toughened poly(lactic acid) (PLA) blend was investigated. Annealing was used to govern the crystallization microstructure and hence the mechanical properties of the blend. Crystallization resulted in the morphology of the PLA component altering from a continuous amorphous phase to continuous crystalline phase. Moreover, as the crystallization of PLA proceeded, the degree of crystallinity, spherulite size and lamellar thickness increased, and the interlamellar and interspherulitic connections became weaker. These led to the large plastic deformation in the matrix during tension being suppressed, and cracks appeared easily under tensile load, which was favorable to fracture for the blend during tension and so a small elongation at break was obtained. However, the elongation at break for all the annealed specimens was higher than that for neat amorphous PLA, suggesting that PEBA still showed a toughening effect for PLA under annealing. © 2012 Society of Chemical Industry
Robotic‐assisted laparoscopic primary repair of acute iatrogenic colonic perforation: case report
Authors: Pedraza Rodrigo , Ragupathi Madhu , Martinez Tara , Haas Eric M.
Published: June 2012

Background

Colonic perforation during colonoscopy is a rare complication and is usually considered a surgical emergency. Traditionally, such perforations have required laparotomy with repair or resection. Minimally invasive approaches have recently been successfully implemented. We describe our initial experience with a robotic‐assisted laparoscopic technique for primary colorrhaphy following colonoscopic perforation.

Methods

An 84 year‐old female presented with an acute sigmoid perforation identified during colonoscopy. Laparoscopic exploration revealed a full‐thickness tear into the sigmoid mesentery, which was primarily repaired using robotic‐assisted technique.

Results

The procedure was successfully completed in 135 min with an estimated blood loss of 25 ml. There were no intraoperative complications or need for open conversion. The patient was discharged after 4 days without further hospitalization or secondary surgical intervention.

Conclusion

In the presented case, robotic primary colorrhaphy was demonstrated to be a safe and feasible alternative for the management of acute colonoscopic perforation and may warrant consideration in the emergency setting. Copyright © 2012 John Wiley & Sons, Ltd.
Physical layer DVB‐SH performance prediction based on mutual information
Authors: Chauvet W. , Lacan J. , Amiot‐Bazile C. , Lacoste F. , Ros B.
Published: June 2012

Digital Video Broadcasting‐Satellite Handled (DVB‐SH) is a hybrid satellite terrestrial broadcasting standard dedicated to provide video or audio services for handheld terminals. On the satellite part, this standard can make use of interleaving mechanisms to mitigate the effects of the Land Mobile Satellite channel. As a result, these mechanisms enable the in‐time distribution of a codeword over a duration ranging from 100 ms to about 30 s, depending on their parameters. This mechanism significantly improves the error recovery performance of the code; however in the literature, a theoretical evaluation at system level of this improvement is missing. Moreover, carrying out Monte‐Carlo simulations implementing real decoding processes on significant traveled distances is time prohibitive.

We propose hereafter a prediction method compatible with fast simulations to quantitatively evaluate the system performance in terms of Rate, Erroneous Second Ratio, and zapping time. This method is based on the computation of the mutual information between emitted and received symbols for QPSK modulation and turbo coding.

We demonstrate that our method reaches a prediction precision of the order of 0.1 dB, which is significantly better than two classical prediction methods. Moreover, our solution reduces the simulation time by a factor of 500 compared with Monte‐Carlo. Beyond DVB‐SH application, the presented approach can be applied in a large panel of satellite mobile systems and is completely new for the satellite community. Copyright © 2012 John Wiley & Sons, Ltd.
Designing role‐based access control using formal concept analysis
Authors: Kumar Ch. Aswani
Published: June 2012

Role‐based access control (RBAC) is one of the most popular and widely deployed access control model. The objective of this paper is to design an RBAC using formal concept analysis, which is based on mathematical lattice and order theory. For this purpose, we derive a dyadic formal context from the triadic security context that represents role‐based access permission and perform attribute exploration from formal concept analysis. We demonstrate the proposed method on a health care ad hoc network. The analysis indicates that the proposed method follows the RBAC constraints: static separation of duties and role hierarchy. Copyright © 2012 John Wiley & Sons, Ltd.
Certificateless broadcast authentication for vehicular ad hoc networks
Authors: Ryu Eun‐Kyung , Yoo Kee‐Young
Published: June 2012

The technology of vehicular ad hoc networks allows vehicles communicate with road‐side infrastructure or with nearby vehicles, supporting a wide range of promising vehicular communication applications and services. It relies on the periodic transmission of packets, called beaconing, as single‐hop link‐layer broadcast to nearby vehicles or road‐side units. However, because of the inherent broadcast nature of the wireless channels, beacon messages are easily exposed to security attacks, such as spoofing, manipulation, or replaying. In this paper, we propose a new certificateless broadcast authentication scheme for securing beacon messages in vehicular networks, which uses the mechanism of Schnorr signature as an underlying primitive. The main goal of our scheme is not to impose the requirement of the public key infrastructure (PKI) that makes existing schemes impractical. Our scheme has a number of crucial advantages. It mitigates the PKI requirement but without degrading any security strength. Consequently, it surpasses existing PKI‐based solutions in terms of both the communication and computation overhead associated with certificates. We also show how the scheme can be extended to provide a practical solution for the problem of key distribution in general‐purpose vehicular applications. Copyright © 2012 John Wiley & Sons, Ltd.
Misspecification of Cox regression models with composite endpoints
Authors: Wu Longyang , Cook Richard J.
Published: June 2012

Researchers routinely adopt composite endpoints in multicenter randomized trials designed to evaluate the effect of experimental interventions in cardiovascular disease, diabetes, and cancer. Despite their widespread use, relatively little attention has been paid to the statistical properties of estimators of treatment effect based on composite endpoints. We consider this here in the context of multivariate models for time to event data in which copula functions link marginal distributions with a proportional hazards structure. We then examine the asymptotic and empirical properties of the estimator of treatment effect arising from a Cox regression model for the time to the first event. We point out that even when the treatment effect is the same for the component events, the limiting value of the estimator based on the composite endpoint is usually inconsistent for this common value. We find that in this context the limiting value is determined by the degree of association between the events, the stochastic ordering of events, and the censoring distribution. Within the framework adopted, marginal methods for the analysis of multivariate failure time data yield consistent estimators of treatment effect and are therefore preferred. We illustrate the methods by application to a recent asthma study. Copyright © 2012 John Wiley & Sons, Ltd.
Social change to avert further climate change: defining the scale of change and principles to guide a new strategy
Authors: Byrne John , Kurdgelashvili Lado , Taminiau Job
Published: June 2012

The inability of the international community so far to materially affect the trend in anthropogenic emissions demonstrates the urgent need to formulate an effective response to the threat of climate change. We offer a detailed picture—disaggregated by country—of the social changes necessary to reduce the rate and risk of climate change. We recognize two broad types of social change—changes that either reduce energy intensity or reduce carbon intensity. Through the Kaya identity, we demonstrate that the current business as usual scenario expects a carbon concentration of approximately 660 ppm by 2100, which corresponds to a potentially catastrophic 4.9°C temperature increase. Through a low‐carbon‐emissions scenario built on principles used by the Center for Energy and Environmental Policy over the past 20 years, we show the social changes required to realize a hopefully sustainable 450 ppm carbon dioxide concentration with an equitable 3.3 ton/capita annual carbon emissions budget. We conclude that all members of the international community—even Non‐Annex 1 members—face major and immediate challenges in any common effort to address climate change. Our analysis supports exploratory efforts for the formulation of menus of social change. As a preliminary basis for identifying such menus of social change, we suggest priority be given to bottom‐up discourses that position the principles of sustainability, equity, development autonomy, and justice at the core of decision‐making.

This article is categorized under:

Energy and Climate > Economics and Policy
The way forward in climate change mitigation
Authors: Pachauri R. K.
Published: June 2012

The year 2012 would mark 20 years since the birth of the United Nations Framework Convention on Climate Change (UNFCCC). As stated under Article 2 of this Convention, the ultimate objective of the UNFCCC is to prevent dangerous anthropogenic interference with the climate system. In support of this objective, the Convention required parties to ‘take precautionary measures to anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects’.

This article is categorized under:

Energy and Climate > Economics and Policy

Energy and Climate > Climate and Environment
Energy strategies to confront climate change
Authors: Lund Peter , Byrne John
Published: June 2012

This article is categorized under:

Energy and Climate > Economics and Policy
A Novel Organosulfonate Cadmium(II) Complex with Graphite‐like 2D Layer Linked by Hydrogen Bonds
Authors: Li Ming‐Tian , Wang Cheng‐Gang , Yang Rui‐Song , Cui Xue‐Jun
Published: June 2012

A novel mixed‐ligand complex, [Cd(im)6][Cd(im)3(H2O)3]2(ans)6·8H2O (1), was obtained from the reaction ofCd(OAc)2·2H2O, imidazole (im) and sodium 4‐aminonaphthalene‐1‐sulfonate tetrahydrate (Na‐ans) in a mixed solvent at 25 °C. The complex was characterized by elemental analysis, IR spectroscopy, and X‐ray single crystal diffraction. There are two kinds of cations constructed by CdII atoms with a octahedral coordination arrangement in 1. The CdII atom is bonded by six nitrogen atoms from six im ligands in the first cation, and the second central CdII atom is bonded by three nitrogen atoms of im molecules and three oxygen atoms belonging to water molecules. The ans anion acts as a counterion to balance the charge, and the adjacent anions are reversed but non‐parallel interlinked by N–H···O(S) hydrogen bonds into graphite‐like 2D sheet viewed from the c axis. The anionic channels along the [110] direction are filled with the cations, and the two kinds of cations are alternatingly arranged in the channels. The hydrogen‐bonding interactions together with the ionic bonds stabilize the crystal structure. The thermostability of the complex was investigated by TG and DSC.
Fast‐Track for the Modern Colorectal Department
Authors: Sehgal Rishabh , Hill Arnold , Deasy Joseph , McNamara Deborah A. , Cahill Ronan A.
Published: June 2012

In recent years, fast‐track or enhanced recovery after surgery (ERAS) colorectal pathways have been utilized to achieve faster recovery and discharge from hospital with swift resumption of normal activities of daily living without an increase in complications or readmissions. Despite the large body of evidence available, however, adoption of the fast‐track methodology in current surgical practice has been slow and sporadic. As outlined by a recent Cochrane review, practice uptake has mostly focused on individual component uptake. Therefore, instead of repeating what already has been established in the literature pertaining to colorectal fast‐track surgery, the aim of this article is to interrogate the evidence concerning the individual components of ERAS pathways as they relate to a contemporary surgical department to determine the most relevant critical components for patients undergoing colorectal surgery in modern surgical practice.