bluuebunny/crossref_metadata_2025 huggingface dataset:
Bridging domain methods for coupled atomistic–continuum models with L2 or H1 couplings
Authors: Guidault P.‐A. , Belytschko T.
Published: September 2008

A bridging domain method for coupled atomistic–continuum models is proposed that enables to compare various coupling terms. The approach does not require the finite element mesh to match the lattice spacing of the atomic model. It is based on an overlapping domain decomposition method that makes use of Lagrange multipliers and weight functions in the coupling zone in order to distribute the energy between the two competing models. Two couplings are investigated. The L2 coupling enforces the continuity of displacements between the two models directly. The H1 coupling involves the definition of a strain measure. For this purpose, a moving least‐square interpolant of the atomic displacement is defined. The choice of the weight functions is studied. Patch tests and a graphene sheet with a crack are studied. It is shown that both continuous and discontinuous weight functions can be used with the H1 coupling whereas the L2 coupling requires continuous weight functions. For the examples developed herein, the L2 coupling produces less error in the zone of interest. The flexibility of the H1 coupling with constant weight function may be beneficial but the results may be affected depending on the topology of the bridging zone. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison study for numerical solution and travelling wave solution for Ito coupled system
Authors: Kawala A.M.
Published: September 2008

In this article, the classical fourth‐order Runge Kutta method and Heun's method are applied to initial value problems for system of ordinary differential equations in nonlinear cases, which we reach it by painaleve analysis, focusing our interest on special case which leads to Travelling wave solution of Ito coupled nonlinear partial differential system. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Scapular stress fracture: a palaeopathological case consistent with crutch use
Authors: Darton Y.
Published: September 2008

This report describes a defect on the right scapula of a 50 to 60 year old male slave who had been buried extra‐muros in the Le Colombier cemetery of Vaison‐la‐Romaine (5th to 6th century AD) in Vaucluse, France. This injury can only be described as a stress fracture, most likely associated with heavy and persistent use of the humerus in abduction. Other bony defects on the skeleton included early signs of ossification of the glenohumeral joint, slight vertebral discopathy, and osteoarthrosis on the right hip. A relationship between scapular stress fractures and walking devices has been described in the current medical literature, and taking this in consideration, possible aetiologies for this scapular defect include either consistent use of a crutch or routine physical labour. Little information is available on either stress fractures or assisted walking devices in antiquity; therefore this information is a valuable contribution to palaeopathology. Copyright © 2008 John Wiley & Sons, Ltd.
Some types of vertebral pathologies in the Argar Culture (Bronze Age, SE Spain)
Authors: Jiménez‐Brobeil S. A. , Oumaoui I. Al , Souich Ph. du
Published: September 2008

A collection of 1825 vertebrae belonging to 105 individuals from several Argaric Culture sites (Bronze Age, SE of Spain) were studied. Several pathologies that could provide information about activity patterns were analysed, including spondylolysis, compression fractures and Schmorl's nodes. Spondylolysis appears exclusively in men. Compression fractures seem to be more related to age (osteoporosis) and are more frequent in women, but without statistical significance. Schmorl's nodes affect a large number of the individuals studied, with a slight predominance in men; there are no differences by age. The results obtained were compared with the available archaeological and anthropological information, which shows a clear division of activities by sex in the Argaric population. The validity of studying these pathologies as activity patterns is discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Two‐component “Onionlike” micelles with a PPO core, a PDMAEMA shell and a PEO corona: formation and crosslinking
Authors: Petrov Petar , Tsvetanov Christo B , Jérôme Robert
Published: September 2008

BACKGROUND: Chemical or physical crosslinking of supramolecular assemblies gives them stability in a wide range of environments. Much attention is paid to multilayer (onion‐like) polymeric micelles because their functionality is higher than classic core‐shell micelles. This work reports on the formation and crosslinking of onion‐like micelles prepared by mixing two different block copolymers containing a crosslinkable poly(dimethylaminoethyl methacrylate) (PDMAEMA) block.

RESULTS: Block copolymers of a crosslinkable PDMAEMA block were synthesized by atom transfer radical polymerization of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) from poly(propylene oxide) (PPO) or poly(ethylene oxide) (PEO) macroinitiators. The (PDMAEMA13)‐block‐PPO69‐block‐(PDMAEMA13) triblock formed wormlike core‐shell micelles, which were converted into ellipsoidal onion‐like micelles on mixing with the PEO45‐block‐P(DMAEMA8‐co‐MMA4) diblock. Onion‐like micelles were crosslinked by quaternization of DMAEMA units.

CONCLUSION: Formation of onion‐like micelles by mixing two different AB (ABA) and B′C block copolymers and their subsequent crosslinking is a valuable approach towards stabilized supramolecular assemblies of a higher complexity and functionality than the individual constitutive components. Copyright © 2008 Society of Chemical Industry
Synthesis, characterization and cleavage of linear polymers attached to silica nanoparticles formed using thiol‐acrylate conjugate addition reactions
Authors: Khire Vaibhav S. , Kloxin April M. , Couch Charles L. , Anseth Kristi S. , Bowman Christopher N.
Published: September 2008

This study investigates the formation of linear polymer grafts using thiol‐acrylate conjugate addition reactions on nanoparticle surfaces. Silica nanoparticles were first modified with an amine functionality, followed by the attachment of a photocleavable acrylate. Dithiol‐diacrylate films were attached to the particles through the surface acrylate groups at various stoichiometric ratios of thiol to acrylate by conducting amine‐catalyzed conjugate addition polymerizations. The particles were then exposed to UV light to release the grafted polymer by photocleavage. The cleaved, grafted polymers were analyzed using infrared spectroscopy and gel permeation chromatography and compared to polymers formed in the bulk, which remained unattached to the particles. The measured number and weight average molecular weights were similar for both polymer types within experimental error and increased from 2000 to 5000 g/mol and 4000 to 10,000 g/mol, respectively, as the ratio of limiting to excess functionality increased from 0.8 to 1. Both number and weight average molecular weights followed the trend of step growth polymers with the highest molecular weight achieved for stoichiometric monomeric mixtures. Surface coverage of the nanoparticles was estimated using the molecular weight and thermogravimetric data and was found to be uniform (∼0.15 chains/nm2) irrespective of the stoichiometry of the reacting monomers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6896–6906, 2008
Heterograft copolymers via double click reactions using one‐pot technique
Authors: Dag Aydan , Durmaz Hakan , Demir Emrah , Hizal Gurkan , Tunca Umit
Published: September 2008

The double click reactions (Cu catalyzed Huisgen and Diels–Alder reactions) were used as a new strategy for the preparation of well‐defined heterograft copolymers in one‐pot technique. The synthetic strategy to the various stages of this work is outlined: (i) preparing random copolymers of styrene (St) and p‐chloromethylstyrene (CMS) (which is a functionalizable monomer) via nitroxide mediated radical polymerization (NMP); (ii) attachment of anthracene functionality to the preformed copolymer by the o‐etherification procedure and then conversion of the remaining CH2Cl into azide functionality; (iii) by using double click reactions in one‐pot technique, maleimide end‐functionalized poly(methyl methacrylate) (PMMA‐MI) via atom transfer radical polymerization (ATRP) of MMA and alkyne end‐functionalized poly (ethylene glycol) (PEG‐alkyne) were introduced onto the copolymer bearing pendant anthryl and azide moieties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6969–6977, 2008
Age‐specific expression of resistance to a neonicotinoid insecticide in the whitefly Bemisia tabaci
Authors: Nauen Ralf , Bielza Pablo , Denholm Ian , Gorman Kevin
Published: September 2008

Neonicotinoid insecticides retain a crucial role within many chemical and integrated control strategies for the tobacco whitefly, Bemisia tabaci Gennadius, in spite of the establishment of potent and widespread resistance in many areas. Metabolic resistance mechanisms mediated by overexpression of P450‐dependent monooxygenases have been implicated in neonicotinoid resistance in the two most prevalent B. tabaci biotypes. Further characterisation of resistance to the neonicotinoid imidacloprid in populations of both these B‐ and Q‐types is reported.

Expression of resistance to imidacloprid was age specific in B‐ and Q‐type strains of B. tabaci. The highest observed resistance ratio at LC50 expressed in prepupal nymphs was 13, compared with at least 580 in their adult counterparts. For all strains, resistance expressed in immatures was not sufficiently potent to compromise recommended imidacloprid application rates.

Targeting neonicotinoids towards immature life stages of B. tabaci may circumvent the protection conferred by current mechanisms of resistance, simultaneously reducing the selection pressures imposed. However, such tactics may enhance the expression of existing resistance mechanisms in immatures, or promote the establishment of novel ones expressed in all life stages. Copyright © 2008 Society of Chemical Industry
Determination of critical points on silicon nanofilms: surface and quantum confinement effects
Authors: Lioudakis Emmanouil , Othonos Andreas , Nassiopoulou A. G.
Published: September 2008

In this work, we present a comprehensive study of the optical properties of nanocrystalline silicon films with thickness varied from 5 to 30 nm. Spectroscopic ellipsometry is employed to determine the dielectric functions of these films using a structural two‐layer model based on the rigorous Airy formula. Our investigation gives an important insight of the origin of critical points for direct and indirect gaps of nanocrystalline silicon films as well as the evolution of them with decreasing the film thickness. The influence of the quantum confinement effect due to the nanoscale grain size and the surface vibrations at the interface on the optical properties are examined in detail. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Semi‐analytical modelling of short channel effects in Si double gate, tri‐gate and gate all‐around MOSFETs
Authors: Tsormpatzoglou A. , Dimitriadis C. A. , Clerc R. , Pananakakis G. , Ghibaudo G.
Published: September 2008

An analytical expression for the three‐dimensional potential distribution along the channel of short channel silicon multi‐gate MOSFETs is described in weak inversion. The analytical solutions cover three different cases of multi‐gate devices: Symmetrical double gate (DG), tri‐gate (TG) and gate‐all‐around (GAA) MOSFETs. Using the three‐dimensional potential distribution in the silicon film, the subthreshold drain current is calculated from which the threshold voltage and the subthreshold swing were extracted. The threshold voltage roll‐off, the subthreshold swing and the drain‐induced barrier lowering of the multi‐gate devices are compared, showing the critical advantage of GAA structures concerning the short channel effects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Physics based capacitance modeling of short‐channel double‐gate MOSFETs
Authors: Børli H. , Vinkenes K. , Fjeldly T. A.
Published: September 2008

A precise compact 2D capacitance model for nanoscale DG MOSFETs in all operating regions is presented. The modeling of the sub‐threshold capacitances is based on the conformal mapping technique, where the corners of the device are treated specifically. In moderate to strong inversion, we obtain self‐consistent results based on the 2D Poisson's equation. The results are in excellent agreement with numerical simulations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of two‐dimensional periodic arrays of metallodielectric nanosandwiches
Authors: Papanikolaou N. , Gantzounis G. , Stefanou N.
Published: September 2008

We report a theoretical study of two‐dimensional periodic arrays of composite particles, consisting of two metallic nanodisks separated by a dielectric spacer, using an efficient and accurate multiple‐scattering method, which was originally developed for systems of spherical particles and recently extended to non‐spherical shapes. In particular, we discuss the plasmonic excitations in such isolated nanosandwiches and study the influence of geometrical parameters like the thickness of the dielectric spacer. Moreover, we investigate the interaction between such composite particles as they approach each other in a two‐dimensional periodic lattice. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomic‐scale configuration of catalyst particles on GaN nanowires
Authors: Kehagias Th. , Komninou Ph. , Dimitrakopulos G. P. , Chèze C. , Geelhaar L. , Riechert H. , Karakostas Th.
Published: September 2008

Well‐aligned single crystalline GaN nanowires were grown on Al2O3 (0001) by molecular beam epitaxy. An initial 0.3 nm thick Ni layer was employed as catalyst. Atomic‐scale electron microscopy observations revealed the epitaxial growth and the crystal quality of the GaN nanowires with basal stacking faults being the only structural defect. Single crystalline droplets on the tip of the nanowires were identified as a Ni‐based cubic oxide with a 0.208 nm {100} lattice spacing and were oriented along [001]/[0001], (010)/(1$ \bar 1 $00) with respect to GaN. Crystal fitting of the two mismatched lattices is realized by a dense network of misfit dislocations at the interface, so that the oxide lattice is relaxed close to its strain‐free value. Analytical methods revealed the positions of the misfit dislocation cores, showing a curved and slightly rough oxide/GaN interface. The observations are consistent with the vapour‐liquid‐solid growth mechanism. Controlled radial growth and thickening of the nanowires was achieved by varying the growth regime. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure investigation of nickel phthalocyanine thin film interfaces with inorganic and organic substrates
Authors: Petraki Fotini , Kennou Stella
Published: September 2008

The interfacial electronic properties of ultra thin films of Nickel Phthalocyanine (NiPc) on inorganic (polycrystalline Au and Ag, sputtered‐ITO) as well as organic (PEDOT:PSS) substrates were compared. The formation of the interfaces was studied by X‐ray and Ultra‐Violet Photoelectron Spectroscopies (XPS, UPS). From the experimental results, information about the interfacial chemistry, band bending in the organic semiconductor and interfacial dipoles was deduced. The valence band structure, the HOMO position and the work function of the NiPc were also determined. The hole injection barrier at the interface was obtained for all substrates and the energy band diagrams were traced in all cases. A Fermi level alignment was found in the interfaces with inorganic substrates, whereas a pinning of the Fermi level was observed with the organic substrate resulting in a significant decrease of the hole injection barrier. All systems investigated divert from the Schottky‐Mott rule and the observed interfacial dipoles appear to increase as the work function value of the substrate increases. The present study shows the importance of the chemical character of the substrate in the electronic properties of the interfaces with an organic semiconductor. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modified MIS‐structure based on nanoporous silicon with enhanced sensitivity to the hydrogen containing gases
Authors: Gorbanyuk T. , Evtukh A. , Litovchenko V. , Solntsev V.
Published: September 2008

The gas sensitivity of metal‐insulator‐semiconductor (MIS)‐structures based on nanoporous silicon with active electrodes from palladium/tungsten oxide composite has been studied. It was found that the using of palladium/tungsten oxide composite (instead of thin palladium film) leads to enhanced sensitivity of MIS structures to hydrogen sulphide in air. The mechanism of this phenomenon has been established. The enhanced H2S sensitivity is explaind in the following way. The microparticles of tungsten trioxide inside palladium matrix stimulate the dissociation of hydrogen sulphide molecules, and hydrogen atoms and/or protons flow down to palladium surface, are absorbed by palladium volume, diffuse to palladium/oxidized nanoporous silicon interface. Hydrogen atoms adsorbed at the interface are polarized and give rise to a dipole layer. As a result, the voltage shift of the capacity‐voltage (C‐V) curve proportional to the measured gas concentration is observed. The surface microstructure of Pd/WO3 composite was studied by AFM microscopy. The chemical content of the composite film has been investigated by SIMS. It was found that the composite film on nanoporous silicon surface poses the holes with the size about 0.05 μm, the mean separation between tungsten oxide microparticles is 1‐2 μm. It also was found that the using of the additional double layer polymer film (polymer film (phthalocyanine zinc)/semicon‐ductor film (cadmium sulphide)) on composite film surface leads to the additional enhancement of the gas sensitivity to hydrogen sulphide. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of two analog buffers implemented with low‐temperature polysilicon thin‐film transistors for active matrix displays applications
Authors: Pappas Ilias , Siskos Stilianos , Ghibaudo Gerard , Dimitriadis Charalambos A.
Published: September 2008

In this paper a comparison in the performance of two analog buffers for Active Matrix Displays (AMDs) applications is presented. The two buffers are implemented by using low‐temperature polysilicon thin‐film transistors (LT poly‐Si TFTs) presenting high immunity to the threshold voltage variations of the TFTs devices. The verification of their functionality and performance was made through simulation with Synopsys HSpice. In order the simulations to be realistic and the performance as close to reality as possible, parameters extraction was made from fabricated LT poly‐Si TFTs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparative evaluation of de‐embedding methods for on‐wafer RF CMOS inductor S‐parameter measurements
Authors: Drakaki M. , Hatzopoulos A. , Siskos S.
Published: September 2008

The impact of existing de‐embedding methods applied on on‐wafer RF s‐parameter measurements to evaluate the characteristics of CMOS integrated inductors is examined. Probe pad and metal interconnect line associated parasitic elements need to be removed (de‐embedded) from on‐wafer measurements of inductors fabricated on silicon substrates for proper evaluation of inductor characteristics, such as inductance, quality factor and resonance frequency. For this purpose a chip was fabricated in 0.5 μm CMOS TM1P twin‐tub AMIS technology (Figure 1), with octagonal and spiral inductors and various types of dummy structures, such as different types of open, and short structures as well as a thru structure. The dummy structures are necessary in order to extract the parasitic element components. The Device‐under‐Test (DUT) was a 3.5 turn octagonal inductor of line width 12 μm, spacing 2 μm and external diameter of 160 μm. Existing de‐embedding methods include the open‐short de‐embedding method, a three‐step de‐embedding method, a pads‐short‐open (psod), and a modified four‐step de‐embedding method. These methods have been tested mostly for small devices such as MOS transistors. The impact of each de‐embedding method on inductor characteristics extraction is evaluated and results show differences in the order of 36% for the value of peak quality factor and a maximum difference of 9% for the resonance frequency. The comparative evaluation of the existing de‐embedding methods is based on results extracted from measured S‐parameter data for measurements up to 20 GHz, as well as on results obtained by using the HFSS EM simulator. Based on the results, the modified four‐step method is the most accurate method, and a discussion of improvements to further increase the accuracy of the de‐embedding is done, for a precise characterization of the DUT. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A real time fingerprint identification system based on the AFS8600 sensor and the C6713 DSP processor
Authors: Tselios K. , Zois E. N. , Livanos N. A. , Nassiopoulos A.
Published: September 2008

In this paper, a fingerprint pre‐process and identification algorithm is implemented using the TMS320C6713 DSP starter kit (DSK) module, along with the Authentec AFS 8600 fingerprint sensor. Database: Acquisition is performed using a solid state sensor. The sensor postulates emerge from the theory of the Electric Field technology. Method: Images are first subjected to a frequency and orientation processing. This is achieved using Gabor‐based filters. This processing has been optimized and implemented on the DSP system. A new method has been developed in order to extract the feature vector of the fingerprint image. A grid, centered at the corepoint of the image, is applied to the fingerprint image in order to derive local information. Classification algorithms are developed, which include training as well as evaluating phase. The types of classifiers used were based on the Bayesian approach along with the K‐nearest neighbour. Results: An identification accuracy of 90% was achieved which is comparable to other procedures described in the literature. Conclusion: The combination of a fingerprint processing and identification algorithm using a low cost sensor and DSP module has been presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Compact current modeling of short‐channel multiple gate MOSFETs
Authors: Kolberg S. , Børli H. , Fjeldly T. A.
Published: September 2008

We present a 2D physics based compact model of the double gate (DG) and the gate‐all‐around (GAA) MOSFET, with emphasis on short‐channel devices of nano‐scale dimensions. The compact model is based on a preprocessing routine based on a self‐consistent framework for electrostatics modeling. For sub‐threshold conditions, we assume that the device body is dominated by the solution of the 2D Laplace electrostatics. This assumption is based on the fact that the field strength at the gates emerging from the mobile charge carriers and the doping are much weaker than the fields related to the capacitive coupling between the contacts and the gates. Therefore, we neglect the body charge term in Poisson's equation, converting it to a Laplace equation. Near threshold, the influence of the electronic charge on the electrostatics is taken into account in the framework model in a precise, self‐consistent manner by combining suitable model expressions with the 2D Poisson's equation in the device body. To this end, we consider the self‐consistent potential distributions along the two symmetry axis. Suitable modeling expressions are applied, whose parameters are determined from the boundary conditions and by enforcing self‐consistency using Poisson's equation. The framework and the compact model give excellent results when compared with numerical simulations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐pressure high‐temperature synthesis of Rh2O3‐II‐type In2O3 polymorph
Authors: Gurlo Aleksander , Dzivenko Dmytro , Kroll Peter , Riedel Ralf
Published: September 2008

The metastability of the bixbyite‐ and corundum‐type In2O3 polymorphs up to 33 GPa (at room temperature) is shown. While compressed (in diamond anvil cells) and laser‐heated, both polymorphs undergo a phase transition to the Rh2O3‐II‐type structure (space group Pbcn, No. 60). The direct transition from bixbyite to Rh2O3‐II structure has not yet been observed for any other oxide.

magnified image

(© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antibacterial Activities of Carbapenem Derivatives and Quantitative Structure–Activity Relationship for Drug Design
Authors: Liu Jian , Zhou Lu , Zuo Zhili
Published: September 2008

β‐Lactams, a class of antibiotics including penicillins, cephems, monobactams, and carbapenems, is widely used. In this work, the Quantitative Structure–Activity Relationship (QSAR) models have been built by Partial Least Squares (PLS), Artificial Neural Network (ANN), and Genetic Algorithm optimized ANN (GA‐ANN) to study the antibacterial activities of carbapenem derivatives. Of the three methods, GA‐ANN is potentially useful in predicting QSAR properties of chemical agents. Furthermore, some novel penem derivatives are designed using classical bioisosterism strategy, and the antibacterial activities are predicted by the built GA‐ANN model without any chemical or biological experiments. In conclusion, the niapenems and thiapenems show good antibiotic activities.
Mass spectrometric investigation of the sequence selectivity for adduction of heterocyclic aromatic amines on single‐strand oligonucleotides
Authors: Jamin Emilien L. , Arquier Delphine , Tulliez Jacques , Debrauwer Laurent
Published: September 2008

Heterocyclic aromatic amines (HAAs) generated during the cooking of meats are known to be genotoxic substances able to form covalent bonds with DNA bases after metabolic activation. This work aimed at the investigation of the influence of the local environment of nucleobases along the nucleotidic sequence on its modification induced by two different HAAs, namely 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP) and 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ), in order to identify possible sequences more susceptible to modification. A systematic study of the neighbouring base effect on the adduction was emphasized. Thus, PhIP and IQ adducts have been synthesized with various T‐rich model single‐strand oligonucleotides displaying different flanking bases (A, G, C or T) at the 3′ or the 5′ side of the targeted guanine, which allowed a comparison of the flanking base effects on adduction. Modified oligonucleotides were then analyzed by high‐performance liquid chromatography (HPLC) coupled to electrospray ionization mass spectrometry. The localization of the modifications induced by PhIP or IQ along the oligonucleotide sequence was achieved by tandem mass spectrometry, and modification yields of the various model sequences were compared. Results indicate a favouring sequence context effect on the G‐C8‐IQ adduct formation with the sequence 5′GGG3′. Although higher than IQ, modification yields observed with PhIP showed a less obvious effect of the neighbouring base on the G‐C8‐PhIP adduct formation, with a preferential sequence 5′GGA/G/T3′. Copyright © 2008 John Wiley & Sons, Ltd.
Targeted borate complex formation as followed with electrospray ionization Fourier transform ion cyclotron mass spectrometry: monomolecular model system and polyborate formation
Authors: Gaspar Andras , Harir Mourad , Lucio Marianna , Hertkorn Norbert , Schmitt‐Kopplin Philippe
Published: September 2008

Fourier transform ion cyclotron resonance mass spectrometry (FTICR‐MS) was applied to identify boric acid(B°)/borate(B−) complexes in a monomolecular model system, composed of aqueous caffeic acid and boric acid/borate solutions in various concentration ratios at pH 9.2. Using negative mode electrospray ionization as a ‘soft’ ionization technique, clusters of polyborate were detected beside the well‐known BL°, BL− and BL complexes. An algorithm for the detection of boron complexes, based on their accurate mass and isotope patterns, is proposed which enabled the assignment of elemental compositions/structural formulae of boron/ligand complexes. We present experimental evidence of self‐oligomerization of up to six borate units with caffeic acid, resulting in stable covalently bound polyborate‐polyol complexes. Copyright © 2008 John Wiley & Sons, Ltd.
Role of metabotropic glutamate receptor 5 in the procholinergic effects of neuropsychotherapeutic compounds
Authors: Tzavara Eleni T. , Wade Mark R. , Davis Richard J. , El Khoury Marie‐Anne , Nomikos George G.
Published: September 2008

We investigated the participation of the metabotropic glutamate receptor type 5 (mGluR5) in mediating increases in cortical acetylcholine (ACh) efflux elicited by established or putative neuropsychotherapeutic compounds, using in vivo microdialysis in rats. The norepinephrine transporter inhibitor atomoxetine, the cannabinoid CB1 receptor antagonist SR141716A, the dopamine D1 receptor agonist dihydrexidine, and the atypical antipsychotic clozapine increased cortical ACh (by about 2–3 fold), whereas the mGluR5 antagonist 2‐methyl‐6‐(phenylethynyl)‐pyridine (MPEP) by itself had no effect. The stimulatory effects of atomoxetine, SR141716A and dihydrexidine on cortical ACh were abolished by pretreatment with MPEP. MPEP also attenuated the stimulatory effect of clozapine on ACh efflux. Thus, mGluR5 activation appears to be involved in the procholinergic effects of compounds that exhibit therapeutic properties or potential in neuropsychiatry. Synapse 62:940–943, 2008. © 2008 Wiley‐Liss, Inc.
Increase in matrix metalloproteinase‐9 levels in the rat medial prefrontal cortex after cocaine reinstatement of conditioned place preference
Authors: Brown Travis E. , Forquer Melissa R. , Harding Joseph W. , Wright John W. , Sorg Barbara A.
Published: September 2008

Recently we have shown that inhibition of matrix metalloproteinase (MMP) activity suppresses the reinstatement of cocaine‐primed conditioned place preference (CPP) in rats. Here we explored whether cocaine‐primed reinstatement was associated with increased activity of the gelatinases, MMP‐2 or MMP‐9, in the medial prefrontal cortex (mPFC) or dorsal hippocampus. Male Sprague‐Dawley rats underwent training for cocaine‐CPP followed by extinction sessions and either saline‐ or cocaine‐priming injections. Cocaine‐induced reinstatement produced significant increases in mPFC MMP‐9 activity at 1, 3 and 24 hr after injection compared with saline controls. No changes in MMP‐9 occurred in the hippocampus or in MMP‐2 activity in either brain region. Also, no changes in mPFC MMP‐9 activity were observed 1 hr after reinstatement in animals given no extinction sessions but equivalent time off in the home cage. Finally, MMP‐3 protein levels were not different in either brain region at any of the three time points assessed. These results suggest that an elevation in MMP‐9 activity in the mPFC may contribute to synaptic remodeling important for the reactivation of a cocaine memory, or alternatively, for the modification of a competing extinction memory during reinstatement. Synapse 62:886–889, 2008. © 2008 Wiley‐Liss, Inc.
Mechanisms underlying the honokiol inhibition of evoked glutamate release from glutamatergic nerve terminals of the rat cerebral cortex
Authors: Sy Hiu‐Ngar , Wu Shey‐Lin , Wang Wang‐Fu , Wang Su‐Jane
Published: September 2008

The effect of honokiol, an active component of Magnolia officinalis, on glutamate release from isolated nerve terminals (synaptosomes) was examined. Honokiol potently inhibited 4‐aminopyridine (4‐AP)‐evoked glutamate release in a concentration‐dependent manner, and this effect resulted from a reduction of vesicular exocytosis and not from an inhibition of Ca2+‐independent efflux via glutamate transporter. The inhibitory action of honokiol was not due to decreasing synaptosomal excitability or directly interfering with the release process at some point subsequent to Ca2+ influx, because honokiol did not alter the 4‐AP‐evoked depolarization of the synaptosomal plasma membrane potential or Ca2+ ionophore ionomycin‐induced glutamate release. Rather, examination of the effect of honokiol on cytosolic [Ca2+] revealed that the diminution of glutamate release could be attributed to a reduction in voltage‐dependent Ca2+ influx. Consistent with this, the honokiol‐mediated inhibition of 4‐AP‐evoked glutamate release was completely prevented in synaptosomes pretreated with a wide‐spectrum blocker of N‐, P‐, and Q‐type Ca2+ channels, ω‐conotoxin MVIIC. In addition, honokiol modulation of 4‐AP‐evoked glutamate release appeared to involve a protein kinase C (PKC) signaling cascade, in so far as pretreatment of synaptosomes with the PKC inhibitors Ro318220 or GF109203X all effectively occluded the inhibitory effect of honokiol. Furthermore, honokiol attenuated 4‐AP‐induced phosphorylation of PKC. Together, these results suggest that honokiol effects a decrease in PKC activation, which subsequently attenuates the Ca2+ entry through voltage‐dependent N‐ and P/Q‐type Ca2+ channels to cause a decrease in evoked glutamate exocytosis. These actions of honokiol may contribute to its neuroprotective effect in excitotoxic injury. Synapse 62:890–901, 2008. © 2008 Wiley‐Liss, Inc.
The role of the American Medical Association in product evaluation
Authors: Jerome Joseph B.
Published: September 2008

In the area of soap bacteriostats the concern of the American Medical Association is with safety. Manufacturers who contemplate market tests of consumer products are encouraged to share the scientific information about these products with the appropriate AMA department.
Use of bacteriostats in soap and household cleansing agents
Authors: Vinson Leonard J.
Published: September 2008

In recent years there has been increasing use of antibacterial agents employed in toilet bars to provide deodorant and degerming activity. The common desirable properties of these agents are antibacterial activity at low concentrations, skin substantivity, acceptable color and odor, compatibility with the vehicle, and low irritation and sensitization potential.

Bacteriostats used for such pruposes are principally bisphenolies, halogenated salicylanilides, and halogenated carbanilides. Methods for assessing their effectiveness and safety are discussed. The polybrominated salicylanilides represent a versatile group of bacteriostats which enjoys increasing acceptability in toilet bars and also provides benefits in such household products as liquid detergents, granulated detergents, hard‐surface disinfectant cleansers, and aerosol disinfectant sprays.
In vitro evaluation of the tissue substantivity of selected antibacterial agents
Authors: McNamara T. F. , Steinbach M.
Published: September 2008

Selected compounds and selected synergistic combinations have been evaluated for activity againstS. aureus and for tissue substantivity. No direct correlation could be found between antibacterial activity and tissue substantivity. It was also apparent that the mode of action by which a compound or mixtures of compounds inhibit the growth of organisms is not directly related to the mechanism of tissue substantivity. Preliminary data indicate that no simple explanation of tissue substantivity can be made on the basis of chemical structure. Until more is known about the mechanism of tissue substantivity, each compound will have to be evaluated separately.
Methods for determining the distribution of bacteria in the skin
Authors: Updegraff David M.
Published: September 2008

Five methods used to study bacteria in the skin are reviewed: swabbing, scrubbing, or scraping; biopsy; impression plate; adhesive stripping; and air‐sampling for bacteria‐shedders.

Scraping and swabbing methods give only a rough idea of the numbers and kinds of bacteria on a given area of skin. More recent adaptations of these techniques have introduced the use of soaps or surfactants to disperse the bacteria, followed by quantitative plate counts on serial dilutions. Biopsy methods are little used because they give only qualitative results and are traumatic to the experimental subject. Impression plates give low counts in most cases and enumerate only those bacteria which are lying on the surface layer of thestratum corneum. Adhesive stripping methods are the only ones which give a precise determination of the distribution of colonies of bacteria with regard to both area and depth in thestratum corneum. Counts run much higher than impression plates.
Micellar properties of polyoxyethylene nonylphenol ether in anhydrous and hydrous cyclohexane
Authors: Sharma R. K. , Cowie J. M. G. , Sirianni A. F.
Published: September 2008

A polyoxyethylated nonylphenol ether containing an average of about 10 moles ethylene oxide per mole of hydrophobe was examined in hydrous and in anhydrous cyclohexane by light‐scattering at 45C and by vapor‐pressure measurements with the dry solvent at 39.1C. Stability was assessed by carrying out turbidity measurements over a period of two weeks. The aggregation number was found to increase with added water. The difference between weight and number average molecular weight was very small in dry cyclohexane.
Polymerization of dehydrated castor acids using an acid earth catalyst
Authors: Silverstone G.
Published: September 2008

The atmospheric pressure polymerization of a commercial dehydrated castor oil fatty acid mixture, by using as catalyst the acid clay Filtrol 13, has been studied under different conditions of temperature, catalyst concentration, reaction time, and concentration of conjugated linoleic acid in the starting material. At 180C or above, extremely rapid polymerization of the conjugated fatty acids occurred (50% complete in about 4 min at 66% concentration). This was accompanied bytrans isomerization and some hydrogen transfer to form oleic (oriso‐oleic) acids. The ratio of dimer/polymer in the product was approximately 2 to 2.5 and was only slightly affected by variation in the reaction conditions.
Nonvolatilealpha‐branched‐chain fatty esters
Authors: Ault W. C. , Eisner A. , Bilyk A. , Dooley C. J.
Published: September 2008

Nonvolatilealpha‐branched carboxylic acids and esters have been prepared by a free radical reaction. Various esters of the reaction products of hexadecanoic and octadecanoic acids with the terminal olefins, octene, decene, and dodecene have been synthesized. Fractional crystallization from acetone is a useful method for preparing these compounds in a highly purified state. Mass spectra confirm that branching is found exclusively at thealpha‐ or 2‐position.
Tidal effects on the organic carbon mineralization rate under aerobic conditions in sediments of an intertidal estuary
Authors: Sasaki Akiko , Hagimori Yu , Nakatsubo Takayuki , Hoshika Akira
Published: September 2008

Laboratory experiments and field measurements were conducted to examine the effect of tide on the organic carbon mineralization rate in sediments under aerobic conditions of an intertidal estuary. Core samples of surface sediments were collected from an intertidal estuary of the Kurose River, Hiroshima, Japan. To mimic low and high tide in the intertidal estuary, organic carbon mineralization rates in the samples were measured in the laboratory under both air‐exposed and submerged conditions. Mineralization rates under air‐exposed conditions were two to five times higher than those under submerged conditions. Field measurements of the rate of CO2 emission from the sediment surface revealed a rapid increase in the rate as the sea level fell during ebb tide. The estimated amount of daily organic carbon mineralization assuming a constantly submerged condition was 30% less than that estimated when considering the semi‐diurnal fluctuation in sea level. These results indicate that tide has a marked impact on the organic carbon mineralization rate in sediments under aerobic conditions on an intertidal estuary, and tidal effects need to be considered when the amount of mineralized organic carbon is estimated.
Use of combined conventional and real-time PCR to determine the epidemiology of feline haemoplasma infections in northern Italy
Authors: Gentilini Fabio , Novacco Marilisa , Turba Maria E. , Willi Barbara , Bacci Maria L. , Hofmann-Lehmann Regina
Published: September 2008

Although knowledge of feline haemotropic mycoplasmas (haemoplasmas) has dramatically improved in recent years, some issues still remain to be elucidated. The aim of the current study was to evaluate the prevalence of feline haemoplasma infections in blood samples collected from cats in northern Italy. A convenience-sample of 307 cats (40 anaemic; 258 non-anaemic; nine with unknown haematocrit [HCT]) was investigated using polymerase chain reaction assays. Furthermore, the date of blood collection, signalment and clinicopathological data were retrospectively evaluated to assess predictors and risk factors for infection. Haemoplasma infections were highly prevalent in the sample investigated with an overall prevalence of 18.9% (95% confidence interval: 14.5–23.3%). The prevalence for the three feline haemoplasmas was 17.3% for ‘ Candidatus Mycoplasma haemominutum’ ( CMhm), 5.9% for Mycoplasma haemofelis ( Mhf) and 1.3% for ‘ Candidatus Mycoplasma turicensis’ ( CMt). Feline immunodeficiency virus-positive status represented a risk factor for infection with an odds ratio of 4.19 ( P=0.02). Moreover, a higher prevalence was observed in summer (odds ratio 1.78; P=0.04) which may be consistent with arthropod-borne disease transmission. Cats infected with Mhf showed significantly lower HCT ( P=0.03), haemoglobin values ( P=0.02) and red blood cell counts ( P=0.04), lower mean corpuscular haemoglobin concentration ( P<0.01) and higher white blood cell counts ( P<0.01) when compared with non-infected cats.
AN ALGORITHM FOR FINDING ALL ZEROS OF VECTOR FUNCTIONS
Authors: ALOLYAN IBRAHEEM
Published: September 2008

Computing a zero of a continuous function is an old and extensively researched problem in numerical computation. In this paper, we present an efficient subdivision algorithm for finding all real roots of a function in multiple variables. This algorithm is based on a simple computationally verifiable necessity test for the existence of a root in any compact set. Both theoretical analysis and numerical simulations demonstrate that the algorithm is very efficient and reliable. Convergence is shown and numerical examples are presented.
Age distribution of cinder cones within the Bandas del Sur Formation, southern Tenerife, Canary Islands
Authors: KRÖCHERT JÖRG , BUCHNER ELMAR
Published: September 2008

The Quaternary Bandas del Sur Formation in the south of Tenerife comprises a complex sequence of pyroclastic rocks and lavas. In contrast to the NW- and NE-Rift zone on Tenerife, the S-Rift zone comprises a number of characteristics with respect to the morphological features, eruption cyclicity and the geochemistry of the volcanic deposits. Various flank eruptions of the Las Cañadas volcano associated with basaltic lavas and the formation of cinder cones within the Bandas del Sur are important volcanic units for understanding the explosive volcanic cycles during the Pleistocene on Tenerife. A number of palaeomagnetic studies, as well as major and trace element geochemistry and two radio-isotope dates (K–Ar), have been carried out on prominent cinder cones, in order to discover their stratigraphic position. Combining our results with previous K–Ar data, the cones and lavas can be subdivided into three stratigraphic units. The first unit contains cinder cones with reverse magnetization and Y/Nb ratios between 0.37 and 0.41. Cinder cones which belong to the second unit show normal magnetization and Y/Nb ratios of < 0.35. The third unit comprises cinder cones with normal magnetization and Y/Nb ratios of about 0.47. The first two units were constructed between c. 0.948–0.779 Ma and 0.323–0.300 Ma. These units define volcanic cycles ending in violent Plinian eruptions. The third and youngest unit possibly marks the beginning of a further volcanic cycle that started c. 0.095 Ma ago.
Cold-hardiness of olive (Olea europaeaL.) cultivars in cold-acclimated and non-acclimated stages: seasonal alteration of antioxidative enzymes and dehydrin-like proteins
Authors: CANSEV A. , GULEN H. , ERIS A.
Published: September 2008

Seasonal patterns of antioxidative enzymes and proteins and their relations to cold-hardiness of nine olive (Olea europaeaL.) cultivars (Ascolona, Domat, Gemlik, Hojoblanca, Lecquest, Manzanilla, Meski, Samanli and Uslu) are documented in the current study. Fully expanded, uniformly sized leaves from 2-year-old shoots of the cultivars were collected from 20-year-old trees in cold-acclimated (CA, in January) and non-acclimated (NA, in July) stages. Leaf samples were exposed to low temperature at 4, −5, −10 and −20°C for 12 h to determine their cold-hardiness (LT50; assessed by electrolyte leakage). Cold-acclimation produced an increase in freezing tolerance of all cultivars (by lowering LT50). Domat and Lecquest were found to have the highest cold-hardiness among the nine cultivars investigated. Ascolona, Gemlik, Hojoblanca had moderate cold-hardiness, while Samanli, Meski, Uslu and Manzanilla were more sensitive. Activities of catalase (CAT: EC 1·11·1·6), ascorbate peroxidase (APX: EC 1·11·1·11) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase significantly varied depending on the cold-acclimation stage and the cold-hardiness level of the cultivars. Activities of the three antioxidative enzymes and total soluble proteins (TSP) were higher in the CA stage than in the NA stage. Although no accumulation of major polypeptides, except a 23 kDa protein, was detected either in CA samples or NA samples by SDS-PAGE, anti-dehydrin immunoblots revealed that the 43 and 23 kDa polypeptides were detectable during cold-acclimation of olive cultivars. Accumulation of both 43 and 23 kDa dehydrin was significantly higher in the CA stage than in the NA stage in all cultivars. Accumulation of 43 kDa dehydrin was correlated with cold-hardiness of the cultivars, while 23 kDa dehydrin was considered as cultivar-dependent since its accumulation was not parallel to LT50values of the cultivars. Indeed, the tissues of cvs Domat, Lecquest, Ascolona, Hojoblanca and Gemlik were found to enhance the structural stability of cellular membranes in the CA stage by increasing both the activity of such enzymes as CAT, APX and NADPH oxidase to activate the antioxidative systems and the expression of 43 kDa dehydrins.
Cognitive processing in bipolar disorder conceptualized using the Interactive Cognitive Subsystems (ICS) model
Authors: Lomax C. L. , Barnard P. J. , Lam D.
Published: September 2008

Background

There are few theoretical proposals that attempt to account for the variation in affective processing across different affective states of bipolar disorder (BD). The Interacting Cognitive Subsystems (ICS) framework has been recently extended to account for manic states. Within the framework, positive mood state is hypothesized to tap into an implicational level of processing, which is proposed to be more extreme in states of mania.

Method

Thirty individuals with BD and 30 individuals with no history of affective disorder were tested in euthymic mood state and then in induced positive mood state using the Question–Answer task to examine the mode of processing of schemas. The task was designed to test whether individuals would detect discrepancies within the prevailing schemas of the sentences.

Results

Although the present study did not support the hypothesis that the groups differ in their ability to detect discrepancies within schemas, we did find that the BD group was significantly more likely than the control group to answer questions that were consistent with the prevailing schemas, both before and after mood induction.

Conclusions

These results may reflect a general cognitive bias, that individuals with BD have a tendency to operate at a more abstract level of representation. This may leave an individual prone to affective disturbance, although further research is required to replicate this finding.