bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural and electrical properties of rapidly annealed Ni/Mo Schottky barriers on n‐type GaN
Authors: Jyothi I. , Reddy V. Rajagopal , Reddy M. Siva Pratap , Choi Chel‐Jong , Bae Jong‐Seong
Published: November 2009

Thermal annealing effects on the electrical and structural properties of Ni/Mo Schottky contacts on n‐type GaN have been investigated by current–voltage (I–V), capacitance–voltage (C–V), Secondary ion mass spectrometer (SIMS), and X‐ray diffraction (XRD) techniques. The extracted Schottky barrier height (SBH) of the as‐deposited contacts was found to be 0.66 eV (I–V), 0.74 eV (C–V). However, both measurements indicate that the barrier height slightly increases when the contacts are annealed at 300 and 400 °C. Experimental results indicate that high quality Schottky contact with barrier height and ideality factor of 0.75 eV (I–V), 0.96 eV (C–V), and 1.13, respectively, can be achieved under 1 min annealing at 500 °C in nitrogen atmosphere. Further, it is observed that the barrier height slightly decreases upon annealing at 600 °C. The above observations establish that the Ni/Mo contact exhibited excellent electrical characteristics even after thermal annealing at 600 °C. Based on the SIMS and XRD analysis, the formation of gallide phases at the Ni/Mo/n‐GaN interface could be the reason for the improvement of SBH after annealing at 500 °C. The above results indicate that the Ni/Mo contact can be promising for metallization scheme for high‐temperature device applications.
Charge transport and recombination in bulk heterojunction solar cells containing a dicyanoimidazole‐based molecular acceptor
Authors: Schubert Marcel , Steyrleuthner Robert , Bange Sebastian , Sellinger Alan , Neher Dieter
Published: November 2009

Carrier transport and recombination have been studied in single component layers and blends of the soluble PPV‐derivative poly[2,5‐dimethoxy‐1,4‐phenylenevinylene‐2‐methoxy‐5‐(2‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene] (M3EH‐PPV) and the small molecule acceptor 4,7‐bis(2‐(1‐hexyl‐4,5‐dicyanoimidazole‐2‐yl)vinyl) benzo[c][1,2,5]‐thiadiazole (HV‐BT). Measurements on single carrier devices show significantly smaller electron mobility in the blend compared to the pure HV‐BT layer, which is suggestive of the formation of isolated clusters of the acceptor in a continuous polymer matrix. The significant change in fill factor (FF) with increasing illumination intensity is consistently explained by a model taking into account bimolecular recombination and space charge effects. The decay of the carrier density after photoexcitation has been studied by performing photo‐CELIV measurements on pure and blend layers. It is found that the decay at long delay times follows a power‐law dependence, which is, however, not consistent with a Langevin‐type bimolecular recombination of free charges. A good description of the data is obtained by assuming trimolecular recombination to govern the charge carrier dynamics in these systems.
Single‐walled carbon nanotube networks growth optimization
Authors: Ansaldo Alberto , Jaybhaye Sandesh , Chiarolini Marco , Di Zitti Ermanno , Ricci Davide
Published: November 2009

In recent years there have been many improvements in quality and yield of single‐walled carbon nanotubes (SWCNTs) obtained by chemical vapour deposition (CVD). Mainstream in research is focused on growing thick vertically aligned forests of SWCNTs. At the same time SWCNT films – usually obtained by spraying and filtration – are one of the most promising candidates to replace indium tin oxide (ITO) as transparent electrodes in solar cells and flat displays. The main limit of those techniques is that usually carbon nanotubes (CNTs) are deposited in the form of thick bundles and are mixed with insulating molecules, such as surfactants, used to try to unbundle the CNTs in solution. Moreover, ultrasonication is in general used to help dispersion, inducing defects in the tubes; the overall effect is to considerably reduce the conductivity of such CNT films. It is our firm belief that a considerable improvement in film quality can come by directly synthesizing the networks onto the substrate via CVD, but this requires achieving a control of the density and quality of the SWCNT networks without losing the planar arrangement. We show here our latest results in enhancing the quality of SWCNT percolating network synthesis by alcohol CVD on silicon oxide substrates using cobalt and nickel acetates as precursors.
PERIPUTOS: Purity evaluated by Raman intensity of pristine and ultracentrifuged topping of single‐wall carbon nanotubes
Authors: Nishide Daisuke , Miyata Yasumitsu , Yanagi Kazuhiro , Tanaka Takeshi , Kataura Hiromichi
Published: November 2009

A quantitative purity evaluation of single‐wall carbon nanotubes (SWCNTs) using resonance Raman spectroscopy was proposed. Linearity between purity and G‐band Raman intensity of isolated SWCNT solution was confirmed and quantitative purity was evaluated directly from an intensity ratio of pristine and high‐purity SWCNTs prepared by ultracentrifugation. We confirmed that the purity evaluated by Raman intensity of pristine and ultracentrifuged topping of SWCNTs [purity evaluated by Raman intensity of pristine and ultracentrifuged topping of single‐wall carbon nanotubes (PERIPUTOS)] gave the same value for the different laser wavelengths and could be applied to any kinds of SWCNT.
Lattice vibrations in graphene nanoribbons from density functional theory
Authors: Gillen Roland , Mohr Marcel , Maultzsch Janina , Thomsen Christian
Published: November 2009

This work shows results of our investigation of the lattice vibrations in graphene nanoribbons with zigzag and armchair type edges, which we performed by the use of density functional theory. The boundary conditions induced by the nanoribbon edges allow for an interpretation of the phonons as fundamental modes and their respective overtones. The calculated phonons show a characteristic dependence on the nanoribbon width. In this context, we considered a possible influence of the antiferromagnetic ground state of zigzag nanoribbons with respect to the phonons. Furthermore, we demonstrate that a mapping of the calculated Γ‐point phonon frequencies of nanoribbons onto the phonon dispersion of graphene corresponds to an “unfolding” of the nanoribbons' Brillouin zone onto that of graphene and yields good agreement. We further show symmetry properties of armchair and zigzag nanoribbons and full phonon dispersions for small‐width nanoribbons.
Light scattering of interacting gold nanorods
Authors: McGuirt Baxter , Kielbasa Jerry , Park Jung‐Ho , Sisco Patrick , Zhang Junping , Peterson Eric , Murphy Catherine , Adams Richard D. , Williams Richard , Carroll David
Published: November 2009

The optical field intensity of light scattering from nanorods of gold has been imaged at distances that are intermediate between the near‐field and far‐field regimes using a near‐field scanning optical microscope (NSOM). For scattering from isolated nanorods the Fraunhofer diffractive behaviour is modified slightly by the dipolar nature of metal nanoantannae as would be expected at these imaging distances. However, when the nanorods are brought into close proximity, interactions between the nanorods alter the scattering behaviour substantially creating large field intensities between the structures. By sampling the field with the near‐field microscope tip scanned at different heights, detailed maps of the scattering profile can be generated.

The NSOM image of far‐field scattered light from an isolated gold nanorod. The nanorod was imaged at a distance of roughly 8 µm above the support substrate using a scanning near‐field microscope operated at constant height mode.

magnified image
Neutralization of quantum stiction with interlocking arrays of gold nanopillars
Authors: Yannopapas Vassilios , Vitanov Nikolay V.
Published: November 2009

By using a rigorous quantum electrodynamic approach we show that it is possible to achieve the neutralization of the Casimir attraction between two adjacent surfaces in the nanometer scale by coating the two planar surfaces with periodic arrays of nanoparticle chains or nanopillars grown normally, on top of the surfaces, in an interleaving pattern. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust control of T‐S fuzzy systems with time‐varying delay using new approach
Authors: Gassara Hamdi , El Hajjaji Ahmed , Chaabane Mohamed
Published: November 2009

This paper aims to design a controller to robustly stabilize uncertain nonlinear systems with time‐varying delay and norm bounded uncertainties via Takagi–Sugeno (T‐S) fuzzy model. The stabilization conditions are given in the form of linear matrix inequalities using a single Lyapunov–Krasovskii functional (LKF) combining the introduction of some relaxation matrices and only one tuning parameter. In comparison with the existing techniques in the literature, the proposed approach has two major advantages. The first is the reduction of computational complexity when the number of IF‐THEN rules, r, is big. The second concerns the conservatism reduction. Several examples are given to show the effectiveness and the merits of the design procedure. Copyright © 2009 John Wiley & Sons, Ltd.
Trajectory‐keeping in satellite formation flying via robust periodic learning control
Authors: Ahn Hyo‐Sung , Moore Kevin L. , Chen YangQuan
Published: November 2009

This paper proposes an iterative learning control (ILC) scheme to ensure trajectory‐keeping in satellite formation flying. Since satellites rotate the earth periodically, position‐dependent disturbances can be considered time‐periodic disturbances. This observation motivates the idea of repetitively compensating for external disturbances such as solar radiation, magnetic field, air drag, and gravity forces in an iterative, orbit‐to‐orbit manner. It is shown that robust ILC can be effectively utilized for satellite trajectory tracking, thus enabling time‐variant formation flying between the leader‐ and follower‐satellites. The validity of the results is illustrated through computational simulations. Copyright © 2009 John Wiley & Sons, Ltd.
Global output regulation for output feedback systems with an uncertain exosystem and its application
Authors: Xu Dabo , Huang Jie
Published: November 2009

This paper presents the solvability conditions for the global robust output regulation problem for a class of output feedback systems with an uncertain exosystem by using output feedback control. An adaptive control technique is used to handle the unknown parameter vector in the exosystem. It is shown that this unknown parameter vector can be exactly estimated asymptotically if a controller containing a minimal internal model is employed. The effectiveness of our approach has been illustrated by an asymptotic tracking problem of a generalized fourth‐order Lorenz system. Copyright © 2009 John Wiley & Sons, Ltd.
A new ‘event‐on‐demand’ synthesizer of rain attenuation time series at Ku‐, Ka‐ and Q/V‐bands
Authors: Carrie Guillaume , Lacoste Frédéric , Castanet Laurent
Published: November 2009

To develop and test real‐time fade mitigation techniques control algorithms, propagation time series are needed. An alternative to using real data collected from propagation experiments is to generate typical fading time‐series making use of climatological characteristics as well as geometrical and radio‐electrical parameters of the link. The objective of this paper is to present a rain attenuation time‐series synthesizer and able to generate events on demand. The model is based on an enhanced version of the Maseng–Bakken stochastic model. In the first part of this paper, the basic principles of the enhanced Maseng–Bakken model are recalled and the parameterization of this channel model is discussed for temperate European climates. Then, the theoretical bases of the Lacoste–Carrie ‘event‐on‐demand’ model and its validation constitute the second part of this paper. The enhanced Maseng–Bakken model is fully stochastic, whereas the Lacoste‐Carrie ‘event‐on‐demand’ one offers the possibility to command the maximum attenuation level and the duration of the synthesized event. Copyright © 2009 John Wiley & Sons, Ltd.
Network patterns and competitive advantage before the emergence of a dominant design
Authors: Soh Pek‐Hooi
Published: November 2009

This study examines the performance implications of the alliance networks of 49 firms that competed for two technology standards in the U.S. local area network industry from 1989 to 1996. During the race to define a dominant design, individual firms attract the suppliers of complements by building alliance networks to favor the firms' preferred technology standard. Controlling for the number of suppliers in each technology standard community and the extent of technical progress achieved by individual firms, the panel data analysis shows that central firms with high ego network density, coupled with a strategic intent to acquire and share knowledge broadly within the technological community, achieve better innovation performance. The size of the technological community and some random events in the early formation of the industry do not provide a sufficient explanation of how these firms gain the diverse support of suppliers or enhance their competitive advantage. By demonstrating the independent and contingent effects of alliance network properties, this study explains how network patterns might enhance or limit the benefits of alliance networks when focal firms embrace different innovation strategies. Copyright © 2009 John Wiley & Sons, Ltd.
Value creation in innovation ecosystems: how the structure of technological interdependence affects firm performance in new technology generations
Authors: Adner Ron , Kapoor Rahul
Published: November 2009

The success of an innovating firm often depends on the efforts of other innovators in its environment. How do the challenges faced by external innovators affect the focal firm's outcomes? To address this question we first characterize the external environment according to the structure of interdependence. We follow the flow of inputs and outputs in the ecosystem to distinguish between upstream components that are bundled by the focal firm, and downstream complements that are bundled by the firm's customers. We hypothesize that the effects of external innovation challenges depend not only on their magnitude, but also on their location in the ecosystem relative to the focal firm. We identify a key asymmetry that results from the location of challenges relative to a focal firm—greater upstream innovation challenges in components enhance the benefits that accrue to technology leaders, while greater downstream innovation challenges in complements erode these benefits. We further propose that the effectiveness of vertical integration as a strategy to manage ecosystem interdependence increases over the course of the technology life cycle. We explore these arguments in the context of the global semiconductor lithography equipment industry from its emergence in 1962 to 2005 across nine distinct technology generations. We find strong empirical support for our framework. Copyright © 2009 John Wiley & Sons, Ltd.
Vorhersage duktilen Festigkeitsversagens von Stahlbauteilen mit Hilfe schädigungsmechanischer Methoden
Authors: Feldmann Markus , Schäfer Dirk , Eichler Björn
Published: November 2009

Nachweise im Grenzzustand der Tragfähigkeit setzen ausreichende Duktilität voraus. Insbesondere bei der Bemessung nach dem Traglastverfahren, im Erdbebenfall, bei Explosion oder Anprall werden die plastischen Reserven von Konstruktionen gefordert, und es muss sichergestellt werden, dass ausreichendes Verformungsvermögen vorliegt und kein sprödes Versagen auftritt. Zur Absicherung der Nachweismodelle werden im Regelfall Versuche bei Raumtemperatur durchgeführt und entsprechende Sicherheitselemente abgeleitet.

Im Rahmen dieses Aufsatzes werden schädigungsmechanische Methoden vorgestellt, die es ermöglichen, das duktile Versagensverhalten von Stahlbauteilen vorherzusagen. Basierend auf einem Grenzzustand zwischen der lokalen plastischen Dehnungsanforderung, die sich aus der globalen Belastung, dem Detail und dem verwendeten Stahl ergibt, und dem lokalem plastischem Dehnungswiderstand, der sich in Abhängigkeit von Stahlsorte, Temperatur und Dehnrate quantifizieren lässt, können in Zukunft realistische Kriterien für die Werkstoffauswahl in der Hochlage bereitgestellt werden. Der nachfolgende Aufsatz zeigt Auszüge aus den Ergebnissen eines Europäischen Forschungsvorhabens [1] zur Bestimmung eines Hochlagenkriteriums für den Stahlbau.

Prediction of ductile failure of steel structures by damage mechanics.

For the verification in the ultimate limit state sufficient ductility is assumed. Especially in plastic design and for seismic events, explosion or impact it has to be ensured, that the structure shows sufficient deformation capacity and the material provides enough ductility in the upper shelf region and brittle fracture is excluded. To validate the verification procedures tests are performed at room temperature and corresponding safety elements are derived.

Within this article methods based on damage mechanics are presented which allow for an estimation of the ductile fracture behaviour of steel structures in the upper shelf. By this means extensive testing may be supplemented or replaced to some extent. Based upon a limit state between local plastic strain requirements arising from loading situation, detail and steel grade, and local plastic strain resistances given in dependency of the material, temperature and strain rate realistic criteria for the selection of material in the upper shelf will be derived.

In the following excerpts of the results of a European project [1] are shown which deals with the derivation of an upper shelf criterion for steel structures.
Instandsetzung der historischen Kettenbrücke Nassau
Authors: Albrecht Gert , Frießem Heinrich , Langen Thiemo
Published: November 2009

Die Kettenbrücke Nassau über die Lahn von dem Ortskern der Stadt Nassau zum Stadtteil Bergnassau ist in jeder Hinsicht ein außergewöhnliches Bauwerk. Die Brückengeschichte reicht weit in das 19. Jahrhundert zurück. Das Stadtbild sowie das Landschaftsbild des Lahntals werden seit 1830 – nun in dritter Generation – nachhaltig von dieser Brücke geprägt. Es ist eine charakteristische Brücke mit besonderer verkehrstechnischer Bedeutung. Sie verbindet Lahnstein und Wiesbaden und befindet sich in zweiter Generation 1927 auf der historischen Bäderstraße. Der Neubau in dritter Generation 2005 fügt sich hier nahtlos ein.

Restoration of the historical chain‐suspension bridge Nassau, Germany.

The old chain‐suspension bridge over the river Lahn from the main city of Nassau to the part Bergnassau is an extraordinary building. The history of the bridge started in the year 1830 (first Generation). This bridge represented the view of the city Nassau and the landscape of the valley of the river Lahn. It is a characteristically bridge with high importance for traffic, because the cities of Lahnstein and Wiesbaden will be included (second Generation, 1927). The new bridge (third Generation, 2005) is also integrated in the view of the Nassau‐City.
Historische Stützen aus Grauguss – Tragsicherheitsnachweise und Ertüchtigung
Authors: Heyde Stefan , Lindner Joachim
Published: November 2009

Die Pflege und Rekonstruktion von historischen Gebäuden ist eine wesentliche Aufgabe des Bauingenieurwesens und zudem von großem wirtschaftlichen Interesse. In Gebäuden aus der Zeit um 1900 sind dabei oft gusseiserne Stützen anzutreffen. Ihre Tragfähigkeit haben diese Bauteile für die bestehenden Lasten längst unter Beweis gestellt; eine Umnutzung ist jedoch in der Regel mit vergrößerten Lasten verbunden, und der Nachweis der Tragfähigkeit muss entsprechend den geltenden Sicherheitsanforderungen erneut erbracht werden. In den aktuellen Normen DIN 18800‐2 [5] und DIN EN 1993‐1‐1 [8] sind historische Baustoffe aber nicht mehr enthalten, so dass derzeit kein gültiges Nachweisverfahren für diese Bauteile existiert. Es wird daher ein Verfahren vorgestellt, mit dem im Sinne eines Ersatzstabverfahrens entsprechend den aktuellen Normen der Stabilitätsnachweis für historische Stützen unter zentrischer und exzentrischer Belastung geführt werden kann. Darüberhinaus wird die Frage diskutiert, inwieweit historische Stützen durch Verfüllen mit selbstverdichtendem Beton ertüchtigt werden können.

Historic grey cast‐iron columns – analysis of structural safety and upgrade.

Cast‐iron columns were used in many industrial and public buildings from round 1900. During renovation the preservation of these historic columns is a current tendency of public authorities as well as an economical interest. Because of the special material properties the strength of these columns cannot be estimated on the base of present design codes for steel structures e. g. DIN EN 1993‐1‐1 (EC 3) [8] or the German stability code DIN 18800‐2 [5].

Thus a proposal for the design check will be presented for centrically and excentrically loaded columns on the basis of actual interaction formulae. Furthermore the strengthening of cast‐iron columns by filling with self compacting concrete will be discussed.
Das schwebende Dach – Die neue Hauptpforte der Firma Trumpf in Ditzingen
Authors: Sobek Werner , Winterstetter Thomas , Hinz Holger
Published: November 2009

Die Firma Trumpf ist Weltmarktführer für Laserschneide‐ und ‐schweißanlagen. Der Hauptsitz der Firma befindet sich in Ditzingen bei Stuttgart. Um den Zugang zum stetig wachsenden Betriebsgelände neu zu fassen, wurde im Eingangsbereich ein neues Pfortengebäude errichtet, das durch seine Formensprache, seine Transparenz und seinen technischen Standard jedem Besucher bereits bei Betreten des Firmengeländes die Kompetenz und Philosophie des Unternehmens anschaulich vermitteln soll.

The floating roof – The new gatehouse of the company Trumpf in Ditzingen, Germany.

Trumpf is a world market leader for laser‐cutting and laser‐welding machines. The headquarters of the company are situated at Ditzingen near Stuttgart. In order to make the entrance to the continuously growing premises more attractive, a new gatehouse was constructed. The gatehouse is to communicate the company's transparency, technological know‐how and technical standards even before the visitors enter the premises themselves. Particular features of the gatehouse are its thin roof cantilevering by about 20?m and the highly transparent façade.
Notch Promotes Radioresistance of Glioma Stem Cells
Authors: Wang Jialiang , Wakeman Timothy P. , Lathia Justin D. , Hjelmeland Anita B. , Wang Xiao-Fan , White Rebekah R. , Rich Jeremy N. , Sullenger Bruce A.
Published: November 2009

Radiotherapy represents the most effective nonsurgical treatments for gliomas. However, gliomas are highly radioresistant and recurrence is nearly universal. Results from our laboratory and other groups suggest that cancer stem cells contribute to radioresistance in gliomas and breast cancers. The Notch pathway is critically implicated in stem cell fate determination and cancer. In this study, we show that inhibition of Notch pathway with γ-secretase inhibitors (GSIs) renders the glioma stem cells more sensitive to radiation at clinically relevant doses. GSIs enhance radiation-induced cell death and impair clonogenic survival of glioma stem cells but not non-stem glioma cells. Expression of the constitutively active intracellular domains of Notch1 or Notch2 protect glioma stem cells against radiation. Notch inhibition with GSIs does not alter the DNA damage response of glioma stem cells after radiation but rather reduces Akt activity and Mcl-1 levels. Finally, knockdown of Notch1 or Notch2 sensitizes glioma stem cells to radiation and impairs xenograft tumor formation. Taken together, our results suggest a critical role of Notch signaling to regulate radioresistance of glioma stem cells. Inhibition of Notch signaling holds promise to improve the efficiency of current radiotherapy in glioma treatment.
To be or not to be? Discursive resources for (Dis‐)identifying with science‐related careers
Authors: Hsu Pei‐Ling , Roth Wolff‐Michael , Marshall Anne , Guenette Francis
Published: November 2009

One of the main objectives of many science educators is to enroll students into science majors and careers. Researchers have investigated students' views of science in terms of factors and influences that guide students to choose science as a career. However, few investigations exist that have studied the forms of language culture makes available for articulating possible careers generally or the ways of grounding (justifying) these possibilities particularly. The purpose of this study is to investigate ways of using language for supporting justifications of career choices in an interview situation. Thirteen high school biology students were interviewed about their career choices. Drawing on discursive psychology as theory and method, we identify four interpretative repertoires that are deployed during the interviews: the (a) formative, (b) performative, (c) consequent, and (d) potential repertoires. These interpretative repertoires do not merely characterize the discourse about different science‐related professions but in fact co‐articulate different science‐related identities. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 1114–1136, 2009
Stabilization and Riesz basis property of two serially connected Timoshenko beams system
Authors: Han Z.J. , Xu G.Q.
Published: November 2009

In this paper we study the stabilization problem and Riesz basis property of two serially connected Timoshenko beams whose left end is simply supported and the right end is free. Suppose that the displacement and bending moments of the beams at the interior node are continuous, but the shearing force and rotational angle are discontinuous. We design the compensator and feedback controllers at the left end and the interior node of the beams so as to derive the beams back to their equilibrium position. We prove that this closed loop system is well‐posed and asymptotically stable. By the spectral analysis, we also show that its root vectors form a Riesz basis with parentheses for the state space. Hence the spectrum determined growth condition holds. Further, we show that this system is not exponentially stable. Finally, we give a numerical simulation of this kind of closed loop system to support our results.
Successful ACL reconstruction with a variant of the pes anserinus
Authors: Patel Shelain , Trehan Ravi K. , Railton Gil T.
Published: November 2009

An anatomical variant of the pes anserinus encountered during anterior cruciate ligament reconstructive surgery which has not been previously described is discussed. During routine harvesting, the sartorius fascia was incised and the semitendinosus and gracilis tendons were identified. At the distal portion, it was noted that each tendon gave off an additional tendinous slip. The slip from the semitendinosus tendon had attached to the gracilis tendon and vice versa, thereby creating a double pes anserinus. This variant was used to construct the graft, and at 1 year review the patient had returned to full sporting activities with no complications encountered.
Facile Synthesis and Tensile Behavior of TiO2 One-Dimensional Nanostructures
Authors: Amin Syed S. , Li Shu-you , Wu Xiaoxia , Ding Weiqiang , Xu Terry T.
Published: November 2009

High-yield synthesis of TiO2 one-dimensional (1D) nanostructures was realized by a simple annealing of Ni-coated Ti grids in an argon atmosphere at 950 °C and 760 torr. The as-synthesized 1D nanostructures were single crystalline rutile TiO2 with the preferred growth direction close to [210]. The growth of these nanostructures was enhanced by using catalytic materials, higher reaction temperature, and longer reaction time. Nanoscale tensile testing performed on individual 1D nanostructures showed that the nanostructures appeared to fracture in a brittle manner. The measured Young’s modulus and fracture strength are ~56.3 and 1.4 GPa, respectively.
Fabrication of a Highly Sensitive Chemical Sensor Based on ZnO Nanorod Arrays
Authors: Park JaeYoung , Choi Sun-Woo , Kim SangSub
Published: November 2009

We report a novel method for fabricating a highly sensitive chemical sensor based on a ZnO nanorod array that is epitaxially grown on a Pt-coated Si substrate, with a top–top electrode configuration. To practically test the device, its O2 and NO2 sensing properties were investigated. The gas sensing properties of this type of device suggest that the approach is promising for the fabrication of sensitive and reliable nanorod chemical sensors.
Antifungal Activity of Leaf Essential Oil and Extracts of Metasequoia glyptostroboides Miki ex Hu
Authors: Bajpai Vivek K. , Kang Sun Chul
Published: November 2009

Plant diseases constitute an emerging threat to global food security. Many of the currently available antifungal agents for agriculture are highly toxic and nonbiodegradable and cause extensive environmental pollution. Moreover, an increasing number of phytopathogens are developing resistance to them. Therefore, the aim of this study was to assess the antifungal efficacy of the leaf essential oil and the leaf extracts of Metasequoia glyptostroboides against Fusarium oxysporum, Fusarium solani, Phytophthora capsici, Colletotrichum capsici, Sclerotinia sclerotiorum, Botrytis cinerea and Rhizoctonia solani. The oil (1,000 μg/disc) and the extracts (1,500 μg/disc) revealed a remarkable antifungal effect against the tested plant pathogenic fungi with a radial growth inhibition percentage of 41.3–66.3% and 13.4–54.4%, respectively along with their respective MIC values ranging from 62.5 to 1,000 μg/ml and 500–4,000 μg/ml. The oil had a strong detrimental effect on spore germination of all the tested plant pathogens along with the concentration as well as time‐dependent kinetic inhibition of Botrytis cinerea. Also, the oil exhibited a potent in vivo antifungal effect against Phytophthora capsici on greenhouse grown pepper plants. The results of this study indicate that the oil and extracts of M. glyptostroboides leaves could become natural alternatives to synthetic fungicides to control certain important plant fungal diseases.
AFM visualization of clathrin triskelia under fluid and in air
Authors: Kotova Svetlana , Prasad Kondury , Smith Paul D. , Lafer Eileen M. , Nossal Ralph , Jin Albert J.
Published: November 2009

Clathrin (uniprotkb:P49951) and Clathrin (uniprotkb:P49951) bind (MI:0407) by atomic force microscopy (MI:0872)
PDE4 inhibitor upregulates PTH‐induced osteoclast formation via CRE‐mediated COX‐2 expression in osteoblasts
Authors: Park Hyojung , No A Long Sae Mi , Lee Jung-Min , Chen Ling , Lee Soo Young , Lee Dong-Seok , Yim Mijung
Published: November 2009

We investigated the interplay between parathyroid hormone (PTH) and phosphodiesterases (PDEs) in osteoblasts. PDE4 negatively regulated PTH‐induced cAMP accumulation. PDE4 inhibitor enhanced PTH‐induced osteoclast formation and RANKL mRNA expression, which is partially mediated by COX‐2 mRNA expression. Two CRE sites in the COX‐2 promoter were required for the increase in COX‐2 transcription by PDE4 inhibitor, and the expression of a dominant‐negative form of CREB abolished COX‐2 mRNA expression in response to PDE4 inhibitor or PTH in osteoblasts. Taken together, our data indicate that PDE4 inhibitor promotes PTH‐induced osteoclast formation partially via CRE‐mediated COX‐2 mRNA expression.
Stakeholder pressure and the adoption of environmental practices: The mediating effect of training
Authors: Sarkis Joseph , Gonzalez‐Torre Pilar , Adenso‐Diaz Belarmino
Published: November 2009

The influence of stakeholder pressure on the adoption of environmental practices has been established in the literature. In this paper we posit that these direct effects are further mediated, causally, by the level of training in companies. Theoretically, this relationship is supported by the relationship between institutional theory (stakeholder pressure) and the dimensions of dynamic capabilities in resource‐based theory. We investigate this relationship within the Spanish automotive industry. The theoretical contribution of this paper focuses on further supporting the relationship between stakeholder and resource‐based theory as complementary theoretical frameworks. The practical implications focus on whether or not training should be integrated in order to help in the adoption of particular environmental practices, which in this study are represented by environmentally oriented reverse logistics practices.
Review Article: Good Governance, Institutions and Economic Development: Beyond the Conventional Wisdom
Authors: Dellepiane-Avellaneda Sebastian
Published: November 2009

This article reviews comparative research on institutions and economic performance, identifying analytical gaps in the political economy of growth literature. It also examines core assumptions underpinning the good-governance approach to development. Contrasting experiences of conceptual and policy issues in East Asia and Latin America are discussed. The author suggests future scholarship in this field should distinguish between the rules and the play of the game; move beyond the property rights approach to development; stress the distributional, endogenous nature of institutions; investigate the role of informal constraints and human learning; and consider sources of credible commitment and self-enforcing growth. Focusing on some uncertainties in the accepted wisdom on good governance and development, this article furthers the consolidation of research on the political foundations of prosperity.
Spatio-temporal mode dynamics and higher order transitions in high aspect ratio Newtonian Taylor–Couette flows
Authors: DUTCHER CARI S. , MULLER SUSAN J.
Published: November 2009

Spatial and temporal frequency dynamics were experimentally tracked via flow visualization for Newtonian fluids as a function of the inner cylinder Reynolds number (Rei) in the flow between concentric, independently rotating cylinders with a radius ratio of 0.912 and an aspect ratio of 60.7. Eight transitions from laminar to turbulent flow were characterized in detail for a stationary outer cylinder, producing highly resolved space–time and frequency–time plots for wavy, modulated and weakly turbulent states. A previously unreported early-modulated wavy vortex flow was found in our high aspect ratio geometry both with and without the presence of a dislocation. The envelope of stability for this flow state was shown to cross into the co-rotating regime, and is present up to Reo ~ 60, where Reo is the outer cylinder Reynolds number. This early modulation is independent of acceleration in the range 0.18 < dRei/dτ < 2.9, where τ is the time nondimensionalized with a viscous time scale. While many of the flow states have been previously observed in geometries with somewhat different radius ratios, we provide new characterization of transitional structures for Reo = 0 in the range 0 < Re* < 21.4, where Re* = Rei/Rec and Rec is the value of Rei at the primary instability. Special attention has been given to ramp rate. For quasi-static ramps, axisymmetric states are stable over the ranges of Re* = [(0–1.17), > 15.4], states characterized by a single distinct temporal frequency for Re* = [(1.17–1.41), (3.56–5.20), (7.85–15.4)], states with multiple temporal frequencies for Re* = [(1.41–3.56), (5.20–7.85)], and a transition from laminar to weakly turbulent vortices occurs at Re* = 5.49. All flow states are characterized by symmetry/symmetry-breaking features as well as azimuthal and axial wavenumbers.
Implicit and explicit affective associations towards cannabis use in patients with recent-onset schizophrenia and healthy controls
Authors: Dekker N. , Smeerdijk A. M. , Wiers R. W. , Duits J. H. , van Gelder G. , Houben K. , Schippers G. , Linszen D. H. , de Haan L.
Published: November 2009

Background

Cannabis use is common in patients with recent-onset schizophrenia and this is associated with poor disease outcome. More insight in the cognitive-motivational processes related to cannabis use in schizophrenia may inform treatment strategies. The present study is the first known to compare implicit and explicit cannabis associations in individuals with and without psychotic disorder.

Method

Participants consisted of 70 patients with recent-onset psychotic disorder and 61 healthy controls with various levels of cannabis use. Three Single-Category Implicit Association Tests (SC-IAT) were used to assess ‘relaxed’, ‘active’ and ‘negative’ implicit associations towards cannabis use. Explicit expectancies of cannabis use were assessed with a questionnaire using the same words as the SC-IAT.

Results

There were no differences in implicit associations between patients and controls; however, patients scored significantly higher on explicit negative affect expectancies than controls. Both groups demonstrated strong negative implicit associations towards cannabis use. Explicit relaxed expectancies were the strongest predictors of cannabis use and craving. There was a trend for implicit active associations to predict craving.

Conclusions

The findings indicate that patients suffering from schizophrenia have associations towards cannabis similar to controls, but they have stronger negative explicit cannabis associations. The strong negative implicit associations towards cannabis could imply that users of cannabis engage in a behaviour they do not implicitly like. Explicit relaxing expectancies of cannabis might be an important mediator in the continuation of cannabis use in patients and controls.
The role of the right parietal lobe in anorexia nervosa
Authors: Nico D. , Daprati E. , Nighoghossian N. , Carrier E. , Duhamel J.-R. , Sirigu A.
Published: November 2009

Background

Patients with anorexia nervosa (AN) overestimate their size despite being severely underweight. Whether this misperception echoes an underlying emotional disturbance or also reflects a genuine body-representation deficit is debatable. Current measures inquire directly about subjective perception of body image, thus distinguishing poorly between top-down effects of emotions/attitudes towards the body and disturbances due to proprioceptive disorders/distorted body schema. Disorders of body representation also emerge following damage to the right parietal lobe. The possibility that parietal dysfunction might contribute to AN is suspected, based on the demonstrated association of spatial impairments, comparable to those found after parietal lesion, with this syndrome.

Method

We used a behavioral task to compare body knowledge in severe anorexics (n=8), healthy volunteers (n=11) and stroke patients with focal damage to the left/right parietal lobe (n=4). We applied a psychophysical procedure based on the perception, in the dark, of an approaching visual stimulus that was turned off before reaching the observer. Participants had to predict whether the stimulus would have hit/missed their body, had it continued its linear motion.

Results

Healthy volunteers and left parietal patients estimated body boundaries very close to the real ones. Conversely, anorexics and right parietal patients underestimated eccentricity of their left body boundary.

Conclusions

These findings are in line with the role the parietal cortex plays in developing and maintaining body representation, and support the possibility for a neuropsychological component in the pathogenesis of anorexia, offering alternative approaches to treatment of the disorder.
Major depression and dimensional representations of DSM-IV personality disorders: a population-based twin study
Authors: Reichborn-Kjennerud T. , Czajkowski N. , Røysamb E. , Ørstavik R. E. , Neale M. C. , Torgersen S. , Kendler K. S.
Published: November 2009

Background

Major depressive disorder (MDD) co-occurs frequently with personality disorders (PDs). The extent to which this results from shared genetic or environmental risk factors remains uncertain.

Method

Young adult twins (n=2801) from the population-based Norwegian Institute of Public Health Twin Panel were assessed at personal interview for DSM-IV lifetime MDD and the 10 Axis II PDs. The relationship between MDD and dimensional representations of all PDs was explored by stepwise logistic regression. Multivariate Cholesky twin models were fitted using the Mx program, and genetic and environmental correlations were estimated.

Results

Dimensional representations of borderline (BPD), avoidant (AVPD) and paranoid personality disorder (PPD) were independently and significantly associated with increased risk for MDD. Multivariate twin modeling indicated that one latent factor accounted for the genetic covariance between MDD and the three PDs. The genetic correlations between MDD and dimensional representations of BPD, AVPD and PPD were +0.56, +0.22 and +0.40 respectively. No sex differences or shared environmental effects were found. The structure of the individual-specific environmental factors influencing MDD and the three PDs were similar to the genetic factors but the environmental correlations were lower: +0.39, +0.23 and +0.27 respectively.

Conclusions

There is substantial overlap between liability factors for MDD and BPD from cluster B, PPD from cluster A and AVPD from cluster C. The vulnerability to general PD pathology and MDD seem to be closely related. The patterns of co-morbidity observed between diverse psychiatric disorders might result from just a few liability factors.
Genetic variation of the reference population for quantitative trait loci research in South African Angora goats
Authors: Visser C. , van Marle-Koster E.
Published: November 2009

The South African Angora goat industry makes the largest contribution to global mohair production. Mohair is a luxury fibre and production of a high quality clip is essential. For many years genetic improvement of Angoras in South Africa was based on quantitative selection. Genome mapping efforts provided new avenues for improvement and a quantitative trait loci (QTL) study was initiated to identify QTL associated with mohair traits. The aim of this study was to describe the genetic diversity of the reference population using the available stud and commercial herds with full phenotypic records. The most appropriate QTL design was identified based on the population structure with regard to the families and number of bucks available for breeding. Four herds, consisting of 1067 pure bred goats in 12 half-sib families, were included. Blood samples were obtained from the herds, 94 markers were tested and diversity parameters were estimated. The average number of alleles per marker varied between 5.4 and 7.2 amongst the herds, whereas the observed heterozygosity varied between 0.59 and 0.67. The genetic structure of these herds was found appropriate for use as a reference population as they showed sufficient genetic variability.
Recognizing textual entailment: Rational, evaluation and approaches
Authors: DAGAN IDO , DOLAN BILL , MAGNINI BERNARDO , ROTH DAN
Published: November 2009

The goal of identifying textual entailment – whether one piece of text can be plausibly inferred from another – has emerged in recent years as a generic core problem in natural language understanding. Work in this area has been largely driven by the PASCAL Recognizing Textual Entailment (RTE) challenges, which are a series of annual competitive meetings. The current work exhibits strong ties to some earlier lines of research, particularly automatic acquisition of paraphrases and lexical semantic relationships and unsupervised inference in applications such as question answering, information extraction and summarization. It has also opened the way to newer lines of research on more involved inference methods, on knowledge representations needed to support this natural language understanding challenge and on the use of learning methods in this context. RTE has fostered an active and growing community of researchers focused on the problem of applied entailment. This special issue of theJNLEprovides an opportunity to showcase some of the most important work in this emerging area.
Translational advances and novel therapies for pancreatic ductal adenocarcinoma: hope or hype?
Authors: Chandana Sreenivasa , Mahadevan Daruka
Published: November 2009

Biological complexity, inaccessible anatomical location, nonspecific symptoms, lack of a screening biomarker, advanced disease at presentation and drug resistance epitomise pancreatic ductal adenocarcinoma (PDA) as a poor-prognosis, lethal disease. Twenty-five years of research (basic, translational and clinical) have barely made strides to improve survival, mainly because of a fundamental lack of knowledge of the biological processes initiating and propagating PDA. However, isolation of pancreas cancer stem cells or progenitors, whole-genome sequencing for driver mutations, advances in functional imaging, mechanistic dissection of the desmoplastic reaction and novel targeted therapies are likely to shed light on how best to treat PDA. Here we summarise current knowledge and areas where the field is advancing, and give our opinion on the research direction the field should be focusing on to better deliver promising therapies for our patients.
Ionospheric foF2 forecast over Europe based on an autoregressive modeling technique driven by solar wind parameters
Authors: Tsagouri I. , Koutroumbas K. , Belehaki A.
Published: November 2009

The development of a new ionospheric forecasting algorithm, called the Solar Wind driven autoregression model for Ionospheric short‐term Forecast (SWIF) is presented. SWIF combines historical and real‐time ionospheric observations with solar wind parameters obtained in real time at the L1 point. This is achieved through the cooperation of an autoregression forecasting algorithm, called Time Series AutoRegressive (TSAR), with the empirical Storm Time Ionospheric Model that formulates the ionospheric storm time response based on solar wind input. The evaluation of SWIF's predictions was principally focused on its performance during selected storm time intervals over Europe. The results demonstrate significant improvement of SWIF's prediction capability over its predecessor, TSAR, significant improvement over climatology and evidence of SWIF's efficiency compared to other forecasting methods. Moreover, the evaluation of SWIF's output over long time periods, that include a wide range of geophysical conditions, suggests that SWIF can be used for prediction up to 24 h ahead.
Opportunities and Challenges to Implementing Quality by Design Approach in Generic Drug Development
Authors: Varu Ramaji K. , Khanna Amit
Published: November 2009

This article presents an overview of the implementation of key elements (Target Product Profile, Critical Quality Attributes, design space and control strategy) of Quality by Design (QbD) — a systemic approach in the case of generic drugs. The basis for this concept is that advanced understanding of variables affecting generic drug (product) quality, either obtained through historical operation or demonstrated through process modelling, justifies the replacement of the traditional process targets with acceptable operational ranges. This article also describes the steps involved in the development of generic drugs, steps through which the QbD concept can be applied, and the opportunities for and challenges to implementing QbD in generic drug development.