bluuebunny/crossref_metadata_2025 huggingface dataset:
A quarter‐century of metrology using synchrotron radiation by PTB in Berlin
Authors: Beckhoff Burkhard , Gottwald Alexander , Klein Roman , Krumrey Michael , Müller Ralph , Richter Mathias , Scholze Frank , Thornagel Reiner , Ulm Gerhard
Published: June 2009

For more than 25 years, the Physikalisch‐Technische Bundesanstalt has been strongly engaged in the field of metrology using synchrotron radiation. In Berlin, this research programme started together with the user operation of the electron storage ring BESSY I in the early 1980s. At the beginning, the work was focused on fundamental radiometry, i.e. using the storage ring as a primary radiation source standard and operating beamlines for source and detector calibration in the vacuum ultraviolet spectral range. Meanwhile, at the electron storage rings BESSY II andMetrology Light Sourcein Berlin‐Adlershof, the activities have been extended to a broad range of fundamental and applied photon metrology in the range from the far infrared to hard X‐rays, including methods like cryogenic radiometry, reflectometry and X‐ray fluorescence spectroscopy. In the present review, we give a short historical introduction to this work, describe our laboratories and the basic radiometric principles, and present examples of recent applications, largely performed within the framework of scientific cooperations with external partners from industry and research. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sensing the electron–electron correlation in solids via double photoemission
Authors: Schumann F. O. , Winkler C. , Kirschner J.
Published: June 2009

We discuss the electron pair emission from surfaces upon the absorption of a single photon, also called double photoemission (DPE). This experiment is particular sensitive to the electron–electron interaction, because for independent electrons the DPE intensity is zero. We outline the experimental development of this technique over the past decade. Going beyond the mere detection of pairs we advanced the instrumentation. Now we are able to measure the kinetic energies and emission angles of a wide angular acceptance. We will show how the available energy is distributed among the electrons and how the angular distributions look like. The latter enabled us to make contact to an important concept of modern solid state theory, namely the exchange–correlation hole. We demonstrate that the exchange–correlation hole manifests itself in a depletion zone of the coincidence intensity around the fixed emission direction of one electron. The experiments were performed at the synchrotron facilities BESSY I and BESSY II. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoemission of Ga1–xMnx As with high Curie temperature and transformation into MnAs of zincblende structure
Authors: Rader O. , Valencia S. , Gudat W. , Edmonds K. W. , Campion R. P. , Gallagher B. L. , Foxon C. T. , Emtsev K. V. , Seyller Th.
Published: June 2009

Epitaxial films of Ga1–x Mnx As, x = 0.08, with a high ferromagnetic ordering temperature (TC = 160 K) grown and post‐growth annealed at low temperature (LT) have been studied in a photoemission experiment. The (100) surfaces were prepared by wet etching to remove surface segregated interstitials. By resonant photoemission at the Mn M‐edge, the appearence of a Mn induced main peak at 4.5 eV binding energy and an intense satellite at ∼7.2 eV are observed in full agreement with our previous work on Ga1–x Mnx As with TC ∼50 K. Mn induced states are also observed around 1 eV to 2 eV but are of weaker intensity than in our previous work which may indicate a depletion of interstitial Mn. In no stage of surface preparation, emission from the gap region was observed where, according to recent local‐density calculations, interstitial Mn would contribute to the spectra. Additional annealing in situ changes the photoemission spectra strongly: The Mn 3d spectral weight increases altogether and the satellite decreases in intensity relative to the Mn 3d main peak and shifts to ∼6.5 eV. Comparison to the literature indicates that zincblende‐type MnAs is formed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An old material in the nanoworld: organic‐inorganic hybrid nanotubes based on γ ‐titanium phosphate layered crystal structure
Authors: Blanco Jesús A. , Khainakov Sergei A. , Khainakova Olena , García José R. , García‐Granda S.
Published: June 2009

We report on the synthesis of organic‐inorganic hybrid nanotubes based on the γ ‐titanium phosphate, Ti (H2PO4)(PO4)·2H2O, layered crystal structure spaced with trioctylamine. These materials have been prepared by using microemulsion‐mediated solvothermal and microwave‐assisted methods. The interlayer distance in the inorganic sheets of the nanotube can be controlled by both the alkyl chain length and the amount of the amine template.

All nanotubes obtained are made up of concentric openended cylinders. The possible reason for having this morphology is discussed combining X‐ray diffraction and transmission electron microscopy data. This simple synthesis‐route will be used to prepare other nanotubes with controlled geometries (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effects of embedding medium and size on optical properties of II‐VI core‐shell nanocrystals
Authors: Cruz R. M. de la , Kanyinda‐Malu C. , Iñarrea J. , Clares F. J. , Santalla S. N.
Published: June 2009

Optical properties of typical II‐VI semiconductor coreshell nanostructures are investigated in a wide range of visible and near‐infrared spectrum of light. Indeed, absorption, scattering and extinction coefficients are calculated in these nanostructures by using the scattering Mie theory in dipole approximation. To implement the calculations, Mie theory requires the dielectric function to be clearly defined, so in this work an explicit expression of frequency‐dielectric function for both the core and shell is used and it includes the phonon and plasmon contributions. The effects of the substitution of the embedding material and the size of nanostructure are investigated on the optical parameters.

In fact, the absorption and scattering coefficients are higher for greater size of the nanocrystals. Higher scattering coefficient is obtained when the embedding medium is polyethylene, while higher absorption is observed when the insulating medium is glass. On the other hand, absorption coefficient is 4 to 5 order of magnitude lesser than the scattering coefficient, then the extinction is mainly due to scattering processes. Finally, good agreement between theoretical and experimental results reported in the literature are obtained for extinction coefficient in II‐VI core‐shell nanostructures (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simultaneous detection of micro‐organisms in water samples for future chip applications: coliform bacteria, non‐mandatory bacteria, hepatitis A virus and noroviruses
Authors: Vale Filipa F. , Silva Ana M. , Granja Ana T. , Vale Maria J. , Vieira Helena
Published: June 2009

The use of surveillance systems demonstrates that waterborne pathogens are responsible for several diseases associated either with consuming of contaminated drinking water or contacting polluted recreational waters. To assure water quality not only mandatory microorganisms should be screened for. Emergent pathogens that represent danger to public health should also be analysed. Culture methods used routinely in water microbiology (bacteriology) laboratories are long time consumable. Moreover some of the emergent pathogens are not represented by conventional indicator bacteria, which limit the screening power of the current methodology. The present study aims at developing a rapid method to simultaneously detect several microorganisms (bacteria, protozoa, and virus) in water samples by the use of a DNA chip (AQUACHIP). Species specific DNA probes were developed based on the data available at public genomes databases. The probes were validated against the tested microorganism and artificial contaminated waters. Validation data shows that the probes may be useful to quickly evaluate water quality. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The stress and microstructure of a‐C multilayers deposited using a filtered cathodic vacuum arc and periodic substrate bias
Authors: Xiao Xiaoling , Partridge Jim , Taylor Matthew , McCulloch Dougal
Published: June 2009

Graded amorphous carbon (a‐C) multilayers have been fabricated at room temperature using a filtered ca‐thodic vacuum arc deposition system. The average incident energy of the carbon ions was varied through‐out the deposition process by applying a sinusoidal substrate bias voltage. After deposition, the micro‐structure of the coatings was investigated using transmission electron microscopy and electron energy loss spectroscopy. The evolution of the density and microstructure in the multilayer a‐C films was explained by the depth dependent variation in stress, resulting from the time dependent ion energy. Low density lay‐ers containing graphitic planes oriented perpendicular to the substrate, were found to form during pauses in deposition. This preferred orientation can be explained by surface relaxation in the presence of a biaxial stress field. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highlighting excitonic optical properties of bundled carbon nanotubes to tailor efficient saturable absorbers
Authors: Gicquel‐Guézo Maud , Nong Hanond , Labbé Christophe , Moréac Alain , Corre Alain Le , Loualiche Slimane
Published: June 2009

We present the ability of bundled carbon nanotubes to replace classical III‐V semiconductor quantum‐wells in nanomaterials‐based devices, such as efficient saturable absorbers. Preliminary study of bundled carbon nanotubes films is presented using scanning electronic microscopy and Raman spectroscopy. Then, performing time‐resolved pump‐probe experiments, we show that excitonic nonlinear optical properties of bundled carbon nanotubes are simultaneously marked by ultrafast subpicosecond absorption recovery time, relative great contrast ratio and total recovery of absorption, in direct comparison with quantum‐wells nanostructures. This first direct comparison attributes strong potential to bundled carbon nanotubes for all‐optical switching devices, as lower‐cost nanomaterials solution. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
III–V semiconductor quantum dots with a magnetic impurity
Authors: Chutia Sucismita , Bhattacharjee A. K.
Published: June 2009

We investigate the hole states in GaAs and InAs quantum dots (QDs) containing a single substitutional Mn impurity, which is a shallow acceptor in the configuration d5+h. For an on‐center Mn, in spherical nanocrystals the hole spectrum is found to retain the bulk level scheme, while the binding energy and the sp –d exchange contribution increase rapidly with decreasing QD size. In contrast, in lens‐shaped self‐assembled QDs the four‐fold ground state is split into two well‐separated doublets, the confinement‐induced enhancement is slower and the effective exchange strength an order‐of‐magnitude smaller than in the bulk. A preliminary study of the twohole states indicates that the ground state in InAs/GaAs QDs is a singlet, almost uncoupled to the Mn spin. We deduce the zero‐field fine structure of the excitonic transitions and compare our results with recently reported photoluminescence spectra (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mode II loading behaviour of intergranular cracks lying on a Σ 17(530)/[001] symmetrical tilt boundary in copper
Authors: Luque Aitor , Aldazabal Javier , Martínez–Esnaola José M. , Sevillano Javier Gil
Published: June 2009

We present Molecular Dynamics (MD) simulations of the shear–coupled migration behaviour of a Σ 17(530)/[001] symmetrical tilt boundary, in the absence or in the presence of nanocracks lying on the grain boundary (GB) plane. The simulations have been performed for copper bicrystals at 300 K. Shear–coupled migration (SCM) occurs in both simulated configurations. For the case of a tilt boundary without nanocracks, the observed results are similar to the ones reported elsewhere.

However, for the case of the Σ 17(530) boundary presenting nanocracks, SCM takes place ahead of the mode II loaded crack tips, but the GB gets pinned by the crack tip. The bulging of the tilt boundary reduces the shear stress on the boundary surface near the tip and hinders mode II crack propagation. The applied stress grows until other deformation mechanisms, such as emission of dislocations from the crack tip vicinity or GB sliding, are activated (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetism in hydro‐ and dehydrogenated benzene
Authors: Vergés J. A. , San‐Fabián E. , Pastor‐Abia L. , Chiappe G. , Louis E.
Published: June 2009

Recently, it has been shown that selective hydrogenation of Polycyclic Aromatic Hydrocarbons (PAH) can lead to high spin molecules. In particular, this is the case of some forms of hydrogenated coronene and coranulenne. In this work, mono‐ and multi‐determinantal methods are used to show that hydrogenation of benzene, and dehydrogenation of benzene and coronene (a highly unlikely process), may lead to species whose ground states are characterized by a large spin degeneracy. Results for dehydrogenated coronene can be explained by Lieb's theorem for bipartite lattices. On the other hand, the theorem does not predict the correct spin of ground states for various forms of hydrogenated and dehydrogenated benzene (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plasma processing of polypyrrole‐heparin thin films on titanium substrates for biomedical applications
Authors: Morozan Adina , Nastase Florin , Dumitru Anca , Nastase Claudia , Vulpe Silviu , Filipescu Mihaela
Published: June 2009

Conducting polymers such as polypyrrole (PPy) offer a new class of material for trial use in biological applications. The plasma polymerization is the process mostly used for the deposition of thin polymer and polymer‐based composite films with a variable amount of functionalities available for reaction with biomolecules. Heparin (Hep) is a potent anticoagulant that can be immobilized on biomaterial surfaces to increase their hemocompatability. Efforts are to attach Hep to polymeric materials. In this context, the strategy followed in this work was based on a plasma deposition of PPy and PPy‐Hep films onto Ti substrate. The PPy and PPy‐Hep films were investigated using Fourier Transform Infrared Spectroscopy (FT‐IR) and Atomic Force Microscopy (AFM). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Switching of a single atomic spin induced by spin injection: Effect of spin relaxation
Authors: Kokado Satoshi , Harigaya Kikuo , Sakuma Akimasa
Published: June 2009

Toward the manipulation of a single atomic spin, we theoretically study the switching of a localized quantum spin induced by spin injection. The system consists of electrode/spin quantum dot/electode junctions, in which the left electrode (right electrode) has conduction electrons with up spin (with down spin), and the dot has the localized quantum spin S = (Sx; Sy; Sz). This S has a uniaxial anisotropic energy, –|D|Sz 2, which shows the bistable potential between Sz = –S and S, with D being an anisotropy constant. Furthermore, S interacts with the atomic vibration. For the initial state of Sz = –S, we consider a situation in which up spin electrons exhibit the spin‐flip tunneling from the left electrode to the right one through an exchange interaction between the electron spin and S. We obtain the time dependence of the current, the expectation value of Sz, and that of the vibration quantum number using the master equation approach, in which a parameter related to the spin relaxation time, τ, is taken into account. On the basis of recent experimental results about an Fe atom on CuN surface [C. F. Hirjibehedin et al., Science 317, 1197 (2007)], we apply this theory to systems of S =2. As results, systems exhibit the switching or nonswitching depending on τ (≠ ∞) and the vibration energy within a period of 5 ns, while systems of τ = ∞ bring about the switching. The switching times are evaluated to be in the range of 0.44 ns – 3.8 ns (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First step to Si photonics: synthesis of quantum dot light‐emitters on GaP substrate by MBE
Authors: Guo Weiming , Bondi Alexandre , Cornet Charles , Folliot Hervé , Létoublon Antoine , Boyer‐Richard Soline , Chevalier Nicolas , Gicquel Maud , Alsahwa Bassem , Corre Alain Le , Even Jacky , Durand Olivier , Loualiche Slimane
Published: June 2009

We have grown InAs and InP quantum dots (QDs) on GaP substrate by Molecular Beam Epitaxy (MBE) and analysed them by Atomic Force Microscopy (AFM) and photoluminescence (PL). AFM images confirm the formation of InAs and InP QDs. Largest InAs QDs density is obtained at a growth temperature of 450 °C and under an AsH3 flux of 0.3SCCM. The evolution of QDs shape and absence of photoluminescence indicate a likely plastic relaxation of the strain between InAs and GaP. Concerning InP/GaP QDs, their lateral size, height and density indicate good quality QDs. Photoluminescence signal has been detected for capped InP/GaP QDs until 180 K. The unchanged peak position with respect to InP coverage is attributed to the nearly constant height of the QDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Field emission properties of carbon nanotube arrays grown in porous anodic alumina
Authors: Angelucci A. , Ciorba A. , Malferrari L. , Odorici F. , Rizzoli R. , Rossi M. , Sessa V. , Terranova M. L. , Veronese G. P.
Published: June 2009

Carbon nanotubes (CNTs), with their excellent electronic properties and extremely high aspect ratio, represent an ideal material for building electron sources based on field emission. Fowler‐Nordheim equation describes quite successfully the field emission phenomenon, especially for single or isolated tips. However, some complications arise when populations of CNTs are considered, where collective effects and large variability in the emitters features influence the measured I–V characteristics. In this work, the emission properties of multi‐walled CNTs grown within ordered anodic alumina templates are investigated. These CNT matrices produce current densities up to some tens of mA/cm2, and the field enhancement factor for collective emission sources can be estimated. Such material can be modelled as an ordered and uniform array of emitters and a simulation of the electrostatic field on the emission tips can be done in order to evaluate the field enhancement factor and its dependence on various geometries. This allows comparing predictions from simulation and experimental measurements, in a direct way. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An analytical model for the rapid intensification of tropical cyclones
Authors: Kieu Chanh Q. , Zhang Da‐Lin
Published: June 2009

The nonlinearity and complexity of the primitive equations have been key obstacles to our understanding of tropical cyclones (TCs), particularly in relation to the dynamical processes leading to their rapid intensification. In this study, an axisymmetric model, in which all nonlinear terms in the horizontal momentum equations are retained, is used to examine analytically the effects of organized deep convection on TC rapid intensification. By prescribing a vertical profile of the vertical motion with exponential growth in the core region, a class of exact time‐dependent solutions for the primary circulations of TCs are obtained. The analytical solutions are shown to capture well many observed dynamical structures in both the core and outer regions and the rapid growth of TCs in terms of maximum winds and central pressure drops.

The analytical solutions reveal that (1) the rotational flows in the inner‐core region grow double‐exponentially, and the central pressure drops occur at rates much faster than the rotational growth; (2) the amplification rates of the primary circulations differ profoundly from those of the secondary circulations; (3) the rotational flows tend to grow from the bottom upwards with the fastest growth occurring at the lowest levels; and (4) the TC growth rates depend critically on the vertical structure of tangential flows, with a faster rate for a lower‐level peak rotation. The nonlinear dynamics are shown to play an important role in the rapid growth of TCs. It is demonstrated that the analytical solutions can also be used to construct dynamically consistent vortices for the initialization of TC models. Limitations and possible improvements of the analytical model are also discussed. Copyright © 2009 Royal Meteorological Society
Covariance localisation and balance in an Ensemble Kalman Filter
Authors: Kepert Jeffrey D.
Published: June 2009

A major limitation of the Ensemble Kalman Filter (EnKF) is that the finite ensemble size introduces sampling error into the background covariances, with severe consequences for atmospheric and oceanographic applications. The negative effects of sampling error are customarily limited by covariance localisation, which earlier studies have suggested may introduce imbalance into the system. The deleterious effects of localisation upon balance are confirmed and detailed here, with localisation producing analyses with weaker geostrophic balance and stronger divergence than are obtained using the unlocalised covariances. These imbalances reduce as the localisation radius is increased, but are argued to be large for typical settings. An improved method for calculating local covariances from an ensemble is presented, in which the localisation is performed in streamfunction–velocity potential (ψ–χ), rather than wind component, space. Analyses using this method better preserve the balances contained within the unlocalised covariance model. This transformation further allows the option of intervariable localisation, in which the cross‐covariances involving χ, which are weak and therefore particularly subject to sampling error, are set to 0 instead of being calculated from the ensemble. The various localisations are compared in a series of identical‐twin experiments, with the new localisations producing analyses that are better balanced and significantly more accurate than the usual approach. The localisation with the χ cross‐covariances set to 0 is shown to be superior for the smaller ensemble sizes but not for the larger, implying that the larger ensembles are capable of resolving some of the true χ cross‐covariance in the test system. Copyright © 2009 Royal Meteorological Society
Assessing the impact of observations on a local numerical fog prediction system
Authors: Rémy S. , Bergot T.
Published: June 2009

As poor visibility conditions have great influence on air traffic, a need exists for accurate, updated fog and low‐cloud forecasts. COBEL–ISBA, a boundary‐layer one‐dimensional numerical model, has been developed for the very short‐term forecasting of fog and low clouds. This forecasting system assimilates the information from a local observation system designed to provide details on the state of the surface boundary layer, as well as that of the fog and low‐cloud layers.

This article aims to assess the influence of each component of the observation system on the initial conditions and low‐visibility forecasts. The objective is to obtain a quantitative assessment of the impact on numerical fog forecasts of using a reduced (for smaller‐sized airports) or enhanced (using a sodar) set of observations. We first used simulated observations, and focused on modelling the atmosphere before fog formation and then on simulating the life‐cycle of fog and low clouds. Within this framework, we also estimated the impact of using a sodar to estimate the thickness of the cloud layer. We showed that the radiative flux observations were the most important of all in cloudy conditions, and that the measurement mast did not have to be higher than 10 m. Using either a sodar or radiative flux to estimate the optical thickness of a cloud layer gave the same scores. Using both of them together did not significantly improve the forecast. Simulations with real observations over a winter of simulations confirmed these findings. Copyright © 2009 Royal Meteorological Society
Design and analysis for the Gaussian process model
Authors: Jones Bradley , Johnson Rachel T.
Published: June 2009

In an effort to speed the development of new products and processes, many companies are turning to computer simulations to avoid the time and expense of building prototypes. These computer simulations are often complex, taking hours to complete one run. If there are many variables affecting the results of the simulation, then it makes sense to design an experiment to gain the most information possible from a limited number of computer simulation runs. The researcher can use the results of these runs to build a surrogate model of the computer simulation model. The absence of noise is the key difference between computer simulation experiments and experiments in the real world. Since there is no variability in the results of computer experiments, optimal designs, which are based on reducing the variance of some statistic, have questionable utility. Replication, usually a ‘good thing’, is clearly undesirable in computer experiments. Thus, a new approach to experimentation is necessary. Published in 2009 by John Wiley & Sons, Ltd.
Lateral distribution of fishes in the main‐channel trough of a large floodplain river: Implications for restoration
Authors: Gutreuter Steve , Vallazza Jonathan M. , Knights Brent C.
Published: June 2009

Major river channels have been extensively altered worldwide. The development of restoration strategies for those alterations requires fundamental information, including the use of large deep channels by fishes. We trawled within parallel paths distributed across the width of the main‐channel trough of the Mississippi River to identify how the lateral distribution of fishes responds to variations in flow ranging from 50% to 200% of the annual median, water temperature ranging from 9 to 29°C and commercial shipping traffic ranging from 0 to 9 vessels per day. Among the species we encountered, only shovelnose sturgeon (Scaphirhynchus platorynchus) were persistent channel residents that remained concentrated along the main‐channel centreline regardless of flow, temperature and traffic. Other persistent residents showed no distinct pattern in lateral distribution, concentrated along the deep channel margins or varied in lateral distribution with flow. Surprisingly, large adult bluegill (Lepomis macrochirus), which are conventionally viewed as limnophils, were the second‐most abundant species in our samples and became increasingly abundant within the deep channel trough as flow decreased below the annual median. Clearly, those fishes exploit resources contained in the main channel and are, therefore, better viewed as opportunistic limno‐rheophils. Our results imply the existence of poorly understood food resources in the main channel. We conjecture that re‐creation of free‐flowing secondary channels and features that increase the production and transport of invertebrates in channels can help mitigate adverse effects of channel alteration and commercial shipping. Published in 2009 by John Wiley & Sons, Ltd.
Influence of habitat restoration on post‐emergence displacement of brown trout (Salmo truttaL.): A case study in a Northern Swedish stream
Authors: Palm Daniel , Lepori Fabio , Brännäs Eva
Published: June 2009

During the 19th and 20th centuries, Swedish streams were channelized to facilitate the commercial transport of timber on water. Stream‐dwelling fish were affected by the consequent reduction in habitat quality. To mitigate the effects on salmonids, which sustain important recreational fisheries, many streams have been restored through the replacement of boulders into the channel since the early 1980s. However, the effects of restoration on salmonids remain poorly known. This study assesses the effect of habitat restoration on the post‐emergence displacement of brown trout (Salmo truttaL.) fry. Hatchery‐raised fry were released in a third‐order stream canalized for timber floating in northern Sweden, and the effect of restoration on displacement was assessed. The short‐term (24 h) displacement of trout fry was reduced from 10.1 to 2.3% of fry released following restoration. Water velocity accounted for 89.4% of the variation in fry displacement across years and sites. Post‐summer recruitment (the proportion of introduced juvenile trout remaining in the study reaches 60 days after the emergence) increased approximately three fold after restoration. These findings suggest that habitat restoration benefit trout populations through substantial reductions of fry displacement and possible contributions to juvenile recruitment. Copyright © 2009 John Wiley & Sons, Ltd.
In‐depth analysis of the satellite component of DVB‐SH: Scenarios, system dimensioning, simulations and field trial results
Authors: Bolea Alamanac Ana , Burzigotti Paolo , De Gaudenzi Riccardo , Liva Gianluigi , Pham Huu Nghia , Scalise Sandro
Published: June 2009

This paper presents a first‐step validation of the satellite component of DVB‐SH obtained by simulations and preliminary on‐field measurements. It is hoped that the results presented will be useful to system designers. The methodology and results presented are expected to be further consolidated by additional on‐field trials with recently launched and soon to be launched commercial S‐band GEO satellites dedicated to DVB‐SH. Copyright © 2009 John Wiley & Sons, Ltd.
Plasmon Coupling in Clusters Composed of Two‐Dimensionally Ordered Gold Nanocubes
Authors: Chen Huanjun , Sun Zhenhua , Ni Weihai , Woo Kat Choi , Lin Hai‐Qing , Sun Lingdong , Yan Chunhua , Wang Jianfang
Published: June 2009

Gold nanocubes are assembled into clusters of varying numbers and ordering on indium tin oxide substrates. The plasmon coupling in the clusters is studied with both dark‐field imaging and finite‐difference time‐domain calculations. Generally, as a cluster becomes larger and more asymmetric, it exhibits more scattering peaks towards longer wavelengths. The coupling of the vertically oriented dipole in the nanocube with its image dipole in the substrate generates two scattering peaks. One is fixed in energy and the other red‐shifts with increasing cluster size. The coupling of horizontally oriented dipoles among different nanocubes produces multiple scattering peaks at lower energies. Their positions and intensities are highly dependent on the number and ordering of nanocubes in the cluster. Au nanocubes in the clusters are further welded together by thermal treatment. The scattering peaks of the thermally treated clusters generally become sharper. The lower‐energy scattering peaks arising from dipolar oscillations are red‐shifted.
An actual test and FE analysis of a steel and concrete composite girder bridge exposed to fire
Authors: Takehara Kazuo , Imagawa Yusuke , Ohyama Osamu , Kurita Akimitsu
Published: June 2009

It has been reported that there are many examples of bridges damaged by fire due to traffic accidents, doubt fires and incendiary fires. When steel and concrete composite girder bridges are exposed to fire, it is necessary to verify the decrease in strength of the structural steel and the concrete. This paper describes the fire test setup for a steel and concrete composite girder bridge. The experimental results are discussed. Furthermore, a finite element analysis is carried out for the steel and concrete composite girder. Finally, the experimental and analytical results are compared.
Vibration factors of overhead sign structures mounted on highway bridges
Authors: Isha Hideo , Kitada Toshiyuki , Nishioka Keiji , Tokumasu Ken
Published: June 2009

Vibration due to traffic and wind causes fatigue damage to overhead sign structures mounted on highway bridges. Fatigue damage due to traffic vibration depends on the type and dimensions of the bridge, type of bearings, volume of traffic, location of overhead sign structures, etc. Factors influencing vibration are investigated in this study by carrying out frequency response analyses, with the parameters being the bridge, bridge pier and bearing types, the location of the sign structures and the weight of the electronic information panels. It can be seen that the damage increased after replacing the steel bearings by elastomeric bearings. These factors were verified through frequency response analyses. The results obtained in this study can be applied to the development of measures to prevent fatigue damage in overhead sign structures due to traffic vibration.
The Munkedal Bridge across the – River Örekil
Authors: Bengtsson Ola , Jansson Berndt , Sala David , Walser Peter
Published: June 2009

This 477 m long steel composite bridge is situated approximately 90 km north of Gothenburg and forms part of the 3000 km long European route E6, which connects Southern Sweden with Northern Norway. The 24.2 m wide steel composite deck is carried by a concrete arch spanning 225 m.
Passerelle sur Nanterre – spatial play of forces
Authors: Keil Andreas , Zimmermann Michael
Published: June 2009

A footbridge was required as part of an urban development project in the Parisian financial district, La Défense. The construction is surrounded by the futuristic and modern architecture of the district, and a technically unique and attractive solution was required.

Together with the architects DFA, Dietmar Feichtinger‐Architectes, Paris, and with the support of the client, EPASA, the ambitious, technically advanced bridge design was constructed and tailored to the specific urban conditions of the site.

The following is an overview of the design concept, elements and calculations plus the fabrication and erection of the bridge.
Concrete overlay of movable steel orthotropic bridge decks
Authors: Boeters Ton , Braam René , Kolstein Henk , Romeijn Arie
Published: June 2009

The deck plate of steel orthotropic bridges is loaded in fatigue by traffic. Increases in both the traffic intensity and the magnitude of the wheel loads have caused premature fatigue cracking of steel bridges in the Netherlands, mostly on very busy motorways. Overlaying the steel orthotropic bridges with 50 mm of heavily reinforced concrete has proved to be a suitable way of reducing the steel stresses at critical locations in the steel deck plate of fixed bridges. This repair method adds no weight to the bridge because the asphalt is simply replaced by a concrete layer.

The self‐weight of the overlay has to meet strict demands in the case of movable bridges because the wearing surface is only a few millimetres thick. Reducing the depth of the overlay might be effective provided the reinforcement is not susceptible to corrosion. Suitable types of reinforcement were researched in an earlier study in which the bending stiffness of the composite structure, the strength of the steel‐concrete interface layer and the bond between the reinforcement and the concrete were investigated in static experiments. The study of the fatigue behaviour of the composite section (concrete layer + steel deck plate) will be discussed in this article.
Altered specifications for the protection of Norwegian steel bridges and offshore structures against corrosion
Authors: Klinge Reidar
Published: June 2009

The ability of thermally sprayed zinc and aluminium to protect steel against corrosion has been exploited for almost 90 years. By further protecting the zinc and the aluminium with paint, some corrosion engineers have expected a service life of at least the sum of the life of the metal plus the life of the paint. Experiences and recent results from research activities have shown that aluminium further coated with thick paint can have a very short life when used in seawater or marine atmospheres.
Inelastic resistance of angle sections subjected to biaxial bending and normal forces
Authors: Vayas Ioannis , Charalampakis Aristotelis , Koumousis Vlasis
Published: June 2009

Steel trusses and other structures with angle section members are usually designed by elastic methods. This may lead to uneconomical designs when these sections are subjected – besides the axial force – to biaxial bending arising not only from eccentric connections, but also from direct transverse loading. This paper provides a simple inelastic interaction formula, Eq. (14), as well as an enhanced inelastic formula, Eq. (27), for the combination of axial force and bending moments about the principal axes which may be used for angle cross‐sections of classes 1 or 2. The formulae do not always exhaust the full plastic cross‐sectional resistance but do lead to a more economical design of the section, especially when bending is dominant. The formulae cover only the design of the cross‐section and do not address stability considerations.
p38 MAP Kinase Inhibits Neutrophil Development Through Phosphorylation of C/EBPα on Serine 21
Authors: Geest Christian R. , Buitenhuis Miranda , Laarhoven Annemieke G. , Bierings Marc B. , Bruin Marrie C.A. , Vellenga Edo , Coffer Paul J.
Published: June 2009

Many extracellular stimuli regulate growth, survival, and differentiation responses through activation of the dual specificity mitogen activated protein kinase (MAPK) kinase three (MKK3) and its downstream effector p38 MAPK. Using CD34+ hematopoietic progenitor cells, here we describe a novel role for MKK3-p38MAPK in the regulation of myelopoiesis. Inhibition of p38MAPK utilizing the pharmacological inhibitor SB203580, enhanced neutrophil development ex vivo, but conversely reduced eosinophil differentiation. In contrast, constitutive activation of MKK3 dramatically inhibited neutrophil differentiation. Transplantation of β2-microglobulin−/− nonobese diabetic/severe combined immune deficient (NOD/SCID) mice with CD34+ cells ectopically expressing constitutively active MKK3 resulted in reduced neutrophil differentiation in vivo, whereas eosinophil development was enhanced. Inhibitory phosphorylation of CCAAT/enhancer binding protein α (C/EBPα) on serine 21 was induced upon activation of p38MAPK. Moreover, ectopic expression of a non-phosphorylatable C/EBPα mutant was sufficient to abrogate MKK3-induced inhibition of neutrophil development. Furthermore, treatment of CD34+ progenitors from patients with severe congenital neutropenia with SB203580 restored neutrophil development. These results establish a novel role for MKK3-p38MAPK in the regulation of lineage choices during myelopoiesis through modulation of C/EBPα activity. This signaling module may thus provide an important therapeutic target in the treatment of bone marrow failure.

Disclosure of potential conflicts of interest is found at the end of this article.
Mesenchymal Stem Cells Pretreated with Delivered Hph-1-Hsp70 Protein Are Protected from Hypoxia-Mediated Cell Death and Rescue Heart Functions from Myocardial Injury
Authors: Chang Woochul , Song Byeong-Wook , Lim Soyeon , Song Heesang , Shim Chi Young , Cha Min-Ji , Ahn Dong Hyuck , Jung Young-Gook , Lee Dong-Ho , Chung Ji Hyung , Choi Ki-Doo , Lee Seung-Kyou , Chung Namsik , Lee Sang-Kyou , Jang Yangsoo , Hwang Ki-Chul
Published: June 2009

Mesenchymal stem cell (MSC) therapy for myocardial injury has inherent limitations due to the poor viability of MSCs after cell transplantation. In this study, we directly delivered Hsp70, a protein with protective functions against stress, into MSCs, using the Hph-1 protein transduction domain ex vivo for high transfection efficiency and low cytotoxicity. Compared to control MSCs in in vitro hypoxic conditions, MSCs delivered with Hph-1-Hsp70 (Hph-1-Hsp70-MSCs) displayed higher viability and anti-apoptotic properties, including Bcl2 increase, reduction of Bax, JNK phosphorylation and caspase-3 activity. Hsp70 delivery also attenuated cellular ATP-depleting stress. Eight animals per group were used for in vivo experiments after occlusion of the left coronary artery. Transplantation of Hph-1-Hsp70-MSCs led to a decrease in the fibrotic heart area, and significantly reduced the apoptotic positive index by 19.5 ± 2%, compared to no-treatment controls. Hph-1-Hsp70-MSCs were well-integrated into the infarcted host myocardium. The mean microvessel count per field in the infarcted myocardium of the Hph-1-Hsp70-MSC-treated group (122.1 ± 13.5) increased relative to the MSC-treated group (75.9 ± 10.4). By echocardiography, transplantation of Hph-1-Hsp70-MSCs resulted in additional increases in heart function, compared to the MSCs-transplanted group. Our results may help formulate better clinical strategies for in vivo MSC cell therapy for myocardial damage.

Disclosure of potential conflicts of interest is found at the end of this article.
Snail and Slug Mediate Radioresistance and Chemoresistance by Antagonizing p53-Mediated Apoptosis and Acquiring a Stem-Like Phenotype in Ovarian Cancer Cells
Authors: Kurrey Nawneet K. , Jalgaonkar Swati P. , Joglekar Alok V. , Ghanate Avinash D. , Chaskar Prasad D. , Doiphode Rahul Y. , Bapat Sharmila A.
Published: June 2009

The transcriptional repressors Snail and Slug contribute to cancer progression by mediating epithelial-mesenchymal transition (EMT), which results in tumor cell invasion and metastases. We extend this current understanding to demonstrate their involvement in the development of resistance to radiation and paclitaxel. The process is orchestrated through the acquisition of a novel subset of gene targets that is repressed under conditions of stress, effectively inactivating p53-mediated apoptosis, while another subset of targets continues to mediate EMT. Repressive activities are complemented by a concurrent derepression of specific genes resulting in the acquisition of stem cell-like characteristics. Such cells are bestowed with three critical capabilities, namely EMT, resistance to p53-mediated apoptosis, and a self-renewal program, that together define the functionality and survival of metastatic cancer stem cells. EMT provides a mechanism of escape to a new, less adverse niche; resistance to apoptosis ensures cell survival in conditions of stress in the primary tumor; whereas acquisition of “stemness” ensures generation of the critical tumor mass required for progression of micrometastases to macrometastases. Our findings, besides achieving considerable expansion of the inventory of direct genes targets, more importantly demonstrate that such elegant cooperative modulation of gene regulation mediated by Snail and Slug is critical for a cancer cell to acquire stem cell characteristics toward resisting radiotherapy- or chemotherapy-mediated cellular stress, and this may be a determinative aspect of aggressive cancer metastases.

Disclosure of potential conflicts of interest is found at the end of this article.
Astrocytes Reverted to a Neural Progenitor-like State with Transforming Growth Factor Alpha Are Sensitized to Cancerous Transformation
Authors: Dufour Christelle , Cadusseau Josette , Varlet Pascale , Surena Anne-Laure , de Faria Giselle P , Dias-Morais Amelie , Auger Nathalie , Léonard Nadine , Daudigeos Estelle , Dantas-Barbosa Carmela , Grill Jacques , Lazar Vladimir , Dessen Philippe , Vassal Gilles , Prevot Vincent , Sharif Ariane , Chneiweiss Herve , Junier Marie-Pierre
Published: June 2009

Gliomas, the most frequent primitive central nervous system tumors, have been suggested to originate from astrocytes or from neural progenitors/stem cells. However, the precise identity of the cells at the origin of gliomas remains a matter of debate because no pre-neoplastic state has been yet identified. Transforming growth factor (TGF)-α, an epidermal growth factor family member, is frequently overexpressed in the early stages of glioma progression. We previously demonstrated that prolonged exposure of astrocytes to TGF-α is sufficient to trigger their reversion to a neural progenitor-like state. To determine whether TGF-α dedifferentiating effects are associated with cancerous transforming effects, we grafted intracerebrally dedifferentiated astrocytes. We show that these cells had the same cytogenomic profile as astrocytes, survived in vivo, and did not give birth to tumors. When astrocytes dedifferentiated with TGF-α were submitted to oncogenic stress using gamma irradiation, they acquired cancerous properties: they were immortalized, showed cytogenomic abnormalities, and formed high-grade glioma-like tumors after brain grafting. In contrast, irradiation did not modify the lifespan of astrocytes cultivated in serum-free medium. Addition of TGF-α after irradiation did not promote their transformation but decreased their lifespan. These results demonstrate that reversion of mature astrocytes to an embryonic state without genomic manipulation is sufficient to sensitize them to oncogenic stress.
Evaluating Erythropoietin-Associated Tumor Progression Using Archival Tissues from a Phase III Clinical Trial
Authors: Miller Chris P. , Lowe Kimberly A. , Valliant-Saunders Karine , Kaiser Joringel F. , Mattern Dominik , Urban Nicole , Henke Michael , Blau C. Anthony
Published: June 2009

Despite the prevalence of anemia in cancer, recombinant erythropoietin (Epo) has declined in use because of recent Phase III trials showing more rapid cancer progression and reduced survival in subjects randomized to Epo. Since Epo receptor (EpoR), Jak2, and Hsp70 are well-characterized mediators of Epo signaling in erythroid cells, we hypothesized that Epo might be especially harmful in patients whose tumors express high levels of these effectors. Because of the insensitivity of immunohistochemistry for detecting low level EpoR protein, we developed assays to measure levels of EpoR, Jak2 and Hsp70 mRNA in formalin-fixed paraffin-embedded (FFPE) tumors. We tested 23 archival breast tumors as well as 136 archival head and neck cancers from ENHANCE, a Phase III trial of 351 patients randomized to Epo versus placebo concomitant with radiotherapy following complete resection, partial resection, or no resection of tumor. EpoR, Jak2, and Hsp70 mRNA levels varied >30-fold, >12-fold, and >13-fold across the breast cancers, and >30-fold, >40-fold, and >30-fold across the head and neck cancers, respectively. Locoregional progression-free survival (LPFS) did not differ among patients whose head and neck cancers expressed above- versus below-median levels of EpoR, Jak2 or Hsp70, except in the subgroup of patients with unresected tumors (n = 28), where above-median EpoR, above-median Jak2, and below-median Hsp70 mRNA levels were all associated with significantly poorer LPFS. Our results provide a framework for exploring the relationship between Epo, cancer progression, and survival using archival tumors from other Phase III clinical trials.

Disclosure of potential conflicts of interest is found at the end of this article.
The Impacts of the HIV/AIDS Pandemic and Socioeconomic Development on the Living Arrangements of Older Persons in Sub‐Saharan Africa: A Country‐Level Analysis
Authors: Cheng Sheung-Tak , Siankam Benjamin
Published: June 2009

This study investigates whether socioeconomic development and the HIV/AIDS pandemic are associated with living arrangement patterns in older persons in 23 sub‐Saharan African countries. Country‐level aggregate data were taken from previous household surveys and information provided by the United Nations, the World Bank, and the World Health Organization. Results showed that 13.5% of older persons (aged 60 years or over) were living with grandchildren but not adult children (i.e., skipped generation households). Countries higher in HIV/AIDS prevalence had more skipped generation households, and also more older persons living with spouse only and fewer older persons living with other relatives. Countries with higher socioeconomic development had fewer older persons living with children younger than 25 years old and more living with spouse only or with other relatives and unrelated persons. The pandemic and socioeconomic development combine to accelerate the breakdown of the extended family structure so that older persons are less and less likely to reside with, and to receive support from, their children.