bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of thermal‐stable and photo‐crosslinkable polyfluorenes for the applications of polymer light‐emitting diodes
Authors: Wang Pei‐Hsuan , Ho Ming‐Shou , Yang Sheng‐Hsiung , Chen Kuei‐Bai , Hsu Chain‐Shu 
Published: December 2009

AbstractThree polyfluorene derivatives which have oxetane‐containing phenyl group at C‐9 position were synthesized via the palladium‐catalyzed Suzuki‐coupling reaction. The synthesized polymers PFB, PFG, and PFR emit blue, green, and red light, respectively. A double‐layer device with the configuration of ITO/PEDOT/polymer/Ca/Al using PFB as the active layer showed a threshold voltage of 5 V, a maximum brightness of 2030 cd/m2, and a maximum current efficiency of 0.35 cd/A. Using PFG as the active layer, the device exhibited a threshold voltage of 6 V, a maximum brightness of 6447 cd/m2, and a maximum current efficiency of 1.27 cd/A. Using PFR as the active layer, the device showed a threshold voltage of 4 V, a maximum brightness of 2135 cd/m2, and a maximum current efficiency of 0.16 cd/A. Better electroluminescent performance was also found based on different design of device structures. Due to photo‐crosslinking property of oxetane groups, the UV‐exposed thin films are insoluble in common organic solvents. A device comprised of blue, green, and red‐emissive pixels was successfully fabricated by spin‐coating and photo‐lithographic processes. In addition, a white light‐emitting device with CIE coordinate of (0.34, 0.33) was achieved by blending PFR into a host material PFB as the active layer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 516–524, 2010
From polymeric particles to multifunctional nanocapsules for biomedical applications using the miniemulsion process
Authors: Landfester Katharina , Musyanovych Anna , Mailänder Volker 
Published: December 2009

AbstractThe miniemulsions process represents a versatile tool for the formation of polymeric nanoparticles consisting of different kinds of polymer as obtained by a variety of polymerization types ranging from radical, anionic, cationic, enzymatic polymerization to polyaddition, and polycondensation. The process perfectly allows the encapsulation of hydrophilic and hydrophobic liquids and solids in polymeric shells, molecularly dissolved dyes or other components. In combination with a specific functionalization of the nanoparticles' or nanocapsules' surfaces and the possibility to release substances in a defined way from the interior, complex nanoparticles or nanocapsules are obtained, which are ideally suited for application in biomedical application as marker and targeted drug‐delivery system. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 493–515, 2010
Nanostructure and mechanical properties studied during dynamical straining of microfibrillar reinforced HDPE/PA blends
Authors: Denchev Zlatan , Dencheva Nadya , Funari Sérgio S. , Motovilin Mladen , Schubert Tom , Stribeck Norbert 
Published: December 2009

AbstractOriented polymer blends whose major component is high‐density polyethylene (HDPE) are strained until failure. Two‐dimensional (2D) small‐angle X‐ray scattering (SAXS) patterns monitor the nanostructure evolution, which is related to the macroscopic mechanical evolution. Data evaluation methods for high‐precision determination of macroscopic and nanoscopic parameters are presented. The hardest materials exhibit a very inhomogeneous nanodomain structure. During straining, their domains appear to be wedged and inhibit transverse contraction on the nanometer scale. Further components of the blends are polyamide 6 (PA6) or polyamide 12 (PA12) (20–30%) and Yparex® 8102 (YP) as compatibilizer (0–10%). Some HDPE/PA6 blends are additionally loaded with commercial nanoclays (Nanomer® or Cloisite®), the respective amounts being 7.5% and 5% with respect to PA. Blending of HDPE with PA12 causes no synergistic effect. In the absence of nanoclay, PA6 and HDPE form a heterogeneous nanostructure with high macroscopic Young's modulus. After addition of YP a rather homogeneous scaffold structure is observed in which some of the PA6 microfibrils and HDPE crystallites appear to be rigidly connected, but the modulus has decreased. Both kinds of nanoclay induce a transition in the HDPE/PA6 blends from a structure without transverse correlation among the microfibrils into a macrolattice with 3D correlations among the HDPE domains from neighboring microfibrils. In the range of extensions between 0.7 and 3.5%, the scattering entities with 3D correlation show transverse elongation instead of transverse contraction. The process is interpreted as overcoming a correlation barrier executed by the crystallites in an evasion‐upon‐approaching mechanism. During continued straining, the 3D correlation is reduced or completely removed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 237–250, 2010
Melt crystallization and morphology of poly(ε‐caprolactone)‐poly(ethylene glycol) diblock copolymers with different compositions and molecular weights
Authors: Xu Ying , Zhang Yan , Fan Zhongyong , Li Suming 
Published: December 2009

AbstractRing opening polymerization of ε‐caprolactone was realized in the presence of monomethoxy poly(ethylene glycol) with Mn = 1000 and 2000, using Zn(La)2 as catalyst. The resulting PCL‐PEG diblock copolymers with CL/EO repeat unit molar ratios from 0.2 to 3.0 were characterized by using DSC, WAXD, SEC, and 1H NMR. The crystal phase of PCL blocks exist in all polymers, and the crystallization ability of PCL blocks increases with CL/EO ratio. PEG blocks are able to crystallize for copolymers with CL/EO below 1.0 only. Melt crystallization results were analyzed with Avrami equation. The Averami exponent n is around 3.0 in most cases, in agreement with heterogeneous nucleation with three dimensional growth. The morphology of the crystals was observed by using POM. Rod‐like crystals were found to grow in 1, 3 or 2, 4 quadrants for samples with low molecular weights. In the case of a copolymer with Mn,PEG = 2000 and Mn,PCL = 800, PEG blocks could crystallize and grow on PCL crystals after PCL finished to form rod‐like crystals, leading to formation of poorly or well structured spherulites. The spherulite growth rate (G) was determined at different crystallization temperatures (Tc) ranging from 9 to 49 °C. All the copolymers present a steady G decrease with increasing crystallization temperature due to lower undercooling. On the other hand, increase of CL/EO ratio leads to increase of G in the same Tc range. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 286–293, 2010
Passive infrared thermographic imaging for mobile robot object identification
Authors: Fehlman William L. , Hinders Mark K. 
Published: December 2009

AbstractThe usefulness of thermal infrared imaging as a mobile robot sensing modality is explored, and a set of thermal–physical features used to characterize passive thermal objects in outdoor environments is described. Objects that extend laterally beyond the thermal camera's field of view, such as brick walls, hedges, picket fences, and wood walls, as well as compact objects that are laterally within the thermal camera's field of view, such as metal poles and tree trunks, are considered. Classification of passive thermal objects is a subtle process because they are not a source for their own emission of thermal energy. A detailed analysis is included of the acquisition and preprocessing of thermal images, as well as the generation and selection of thermal–physical features from these objects within thermal images. Classification performance using these features is discussed, as a precursor to the design of a physics‐based model to automatically classify these objects. Published 2009 Wiley Periodicals, Inc.*This article is a US Government work and, as such, is in the public domain of the United States of America.
Attractor networks
Authors: Rolls Edmund T. 
Published: December 2009

AbstractAn attractor network is a network of neurons with excitatory interconnections that can settle into a stable pattern of firing. This article shows how attractor networks in the cerebral cortex are important for long‐term memory, short‐term memory, attention, and decision making. The article then shows how the random firing of neurons can influence the stability of these networks by introducing stochastic noise, and how these effects are involved in probabilistic decision making, and implicated in some disorders of cortical function such as poor short‐term memory and attention, schizophrenia, and obsessive‐compulsive disorder. Copyright © 2009 John Wiley & Sons, Ltd.This article is categorized under:

Computer Science > Neural Networks
Animal learning
Authors: Castro Leyre , Wasserman Edward A. 
Published: December 2009

AbstractPavlov and Thorndike pioneered the experimental study of animal learning and provided psychologists with powerful tools to unveil its underlying mechanisms. Today's research developments and theoretical analyses owe much to the pioneering work of these early investigators. Nevertheless, in the evolution of our knowledge about animal learning, some initial conceptions have been challenged and revised. We first review the original experimental procedures and findings of Pavlov and Thorndike. Next, we discuss critical research and consequent controversies which have greatly shaped animal learning theory. For example, although contiguity seemed to be the only condition that is necessary for learning, we now know that it is not sufficient; the conditioned stimulus (CS) also has to provide information about the occurrence of the unconditioned stimulus (US). Also, animals appear to learn different things about the same stimuli when circumstances vary. For instance, when faced with situations in which the meaning of a CS changes, as in the case of acquisition and later extinction, animals seem to preserve the original knowledge (CS‐US) in addition to learning about the new conditions (CS‐noUS). Finally, we discuss how parallels among Pavlovian conditioning, operant conditioning, and human causal judgment suggest that causal knowledge may lie at the root of both human and animal learning. All of these empirical findings and theoretical developments prove that animal learning is more complex and intricate than was once imagined. Copyright © 2009 John Wiley & Sons, Ltd.This article is categorized under:

Cognitive Biology > Evolutionary Roots of Cognition
Psychology > Comparative Psychology
Dynamics of Alfvén waves in partially ionized astrophysical plasmas
Authors: SHAIKH DASTGEER 
Published: December 2009

AbstractWe develop a two dimensional, self-consistent, compressible fluid model to study evolution of Alfvenic modes in partially ionized astrophysical and space plasmas. The partially ionized plasma consists mainly of electrons, ions and significant neutral atoms. The nonlinear interactions amongst these species take place predominantly through direct collision or charge exchange processes. Our model uniquely describe the interaction processes between two distinctly evolving fluids. In our model, the electrons and ions are described by a single-fluid compressible magnetohydrodynamic (MHD) model and are coupled self-consistently to the neutral fluid via compressible hydrodynamic equations. Both plasma and neutral fluids are treated with different energy equations that adequately enable us to monitor non-adiabatic and thermal energy exchange processes between these two distinct fluids. Based on our self-consistent model, we find that the propagation speed of Alfvenic modes in space and astrophysical plasma is slowed down because these waves are damped predominantly due to direct collisions with the neutral atoms. Consequently, energy transfer takes place between plasma and neutral fluids. We describe the mode coupling processes that lead to the energy transfer between the plasma and neutral and corresponding spectral features.
The effects of task type in Synchronous Computer-Mediated Communication
Authors: Yilmaz Yucel , Granena Gisela 
Published: December 2009

AbstractThis study examines the potential of learner-learner interaction through Synchronous Computer-Mediated Communication (SCMC) to focus learners’ attention on form. Focus on form is operationalized through Language-Related Episodes (LREs), instances where learners turn their attention to formal aspects of language by questioning the accuracy of their own or each other’s language use. The study also compares two task types, jigsaw and dictogloss, with respect to the number and characteristics of LREs. Ten adult intermediate ESL learners from an intensive English language program in the US worked together in dyads to carry out one jigsaw and one dictogloss task in an SCMC environment. Tasks were controlled for content and were presented in two alternative orders. The dictogloss in this study generated more LREs than the jigsaw. LREs were also qualitatively different across task types. Jigsaw LREs were implicit and did not result in incorrectly solved outcomes, whereas dictogloss LREs were explicit and resulted in correctly solved, incorrectly solved, and unresolved outcomes.
EFL students’ vocabulary learning in NS-NNS e-mail interactions: Do they learn new words by imitation?
Authors: Sasaki Akihiko , Takeuchi Osamu 
Published: December 2009

AbstractThe present study investigated Japanese students’ EFL vocabulary development through e-mail interactions with a native English speaker (NS), with primary focus on students’ imitation of new words. According to sociocultural theory, learners can internalize new linguistic knowledge by imitating an expert’s expressions to create his/her own utterances. This study, therefore, specifically examined whether (1) students could imitate the new vocabulary items provided by the NS tutor, and (2) they could retain these items at the end of the project. An examination of the e-mail log showed that students did imitate and use some of the lexis provided by the NS. The results of the post-test also revealed that some of the imitated words were subsequently retained. However, there were some words that had been learned without imitation. The questionnaire survey and the students’ interview comments indicated that students memorized a considerable number of new words provided by the NS by repeatedly reading them in e-mail text, as well as in other learning contexts, such as regular classes and independent study, through noticing, retrieving, and generating the meaning/form of each word (Nation, 2001). The study concluded that vocabulary learning via e-mail takes place not only by a single process such as imitation, but also by a combination of various processes functioning in an integrated manner.
Tight Bounds for Blind Search on the Integers and the Reals
Authors: DIETZFELBINGER MARTIN , ROWE JONATHAN E. , WEGENER INGO , WOELFEL PHILIPP 
Published: December 2009

We analyse a simple random process in which a token is moved in the interval A = {0, . . ., n}. Fix a probability distribution μ over D = {1, . . ., n}. Initially, the token is placed in a random position in A. In round t, a random step sized is chosen according to μ. If the token is in position x ≥ d, then it is moved to position x − d. Otherwise it stays put. Let TX be the number of rounds until the token reaches position 0. We show tight bounds for the expectation Eμ(TX) of TX for varying distributions μ. More precisely, we show that $\min_\mu\{\E_\mu(T_X)\}=\Theta\bigl((\log n)^2\bigr)$. The same bounds are proved for the analogous continuous process, where step sizes and token positions are real values in [0, n + 1), and one measures the time until the token has reached a point in [0, 1). For the proofs, a novel potential function argument is introduced. The research is motivated by the problem of approximating the minimum of a continuous function over [0, 1] with a ‘blind’ optimization strategy.
A Special Safeguard Mechanism for Agricultural Imports: what experience with other GATT/WTO safeguards tells us about what might work
Authors: FINGER J. MICHAEL 
Published: December 2009

AbstractThe success of existing GATT/WTO safeguard or flexibility provisions to sustain long-run liberalization stems from their procedural criteria (e.g., transparent and participatory decisions to impose new import restrictions) overcoming their suspect economic criteria (e.g., injury). The proposed SSM includes no procedural and minimal notification requirements. It would expand by arithmetic formulas the bounds within which a Member might unilaterally impose new import restrictions. Simulations indicate that the formulas provide a poor guide for policy – they would (a) allow an import restriction more often in situations when it is not beneficial than when it is, and (b) in situations in which an import restriction would help, they more often ban it than allow it. If procedural requirements are out – i.e., developing Members insist on a ‘usable’ safeguard – then the simple rule ‘bound rates may be exceeded for a maximum of [x] tariff lines at any one time’ is better economics than the proposed price and volume triggers. (No economic criteria are better than bad economic criteria.) Each Member would have the flexibility to change its lists of Special Products and Sensitive Products, there being a limit on the numbers of products on the lists at any one time.
MEF2 transcriptional activity maintains mitochondrial adaptation in cardiac pressure overload
Authors: el Azzouzi Hamid , van Oort Ralph J. , van der Nagel Roel , Sluiter Wim , Bergmann Martin W. , De Windt Leon J. 
Published: December 2009

AimsThe transcription factor MEF2 is a downstream target for several hypertrophic signalling pathways in the heart, suggesting that MEF2 may act as a valuable therapeutic target in the treatment of heart failure.Methods and resultsIn this study, we investigated the potential benefits of overall MEF2 inhibition in a mouse model of chronic pressure overloading, by subjecting transgenic mice expressing a dominant negative form of MEF2 (DN‐MEF2 Tg) in the heart, to transverse aortic constriction (TAC). Histological analysis revealed no major differences in cardiac remodelling between DN‐MEF2 Tg and control mice after TAC. Surprisingly, echocardiographic analysis revealed that DN‐MEF2 Tg mice had a decrease in cardiac function compared with control animals. Analysis of the mitochondrial respiratory chain showed that DN‐MEF2 Tg mice displayed lower expression of NADH dehydrogenase subunit 6 (ND6), part of mitochondrial Complex I. The reduced expression of ND6 in DN‐MEF2 Tg mice after pressure overload correlated with an increase in cell death secondary to overproduction of reactive oxygen species (ROS).ConclusionOur data suggest that MEF2 transcriptional activity is required for mitochondrial function and its inhibition predisposes the heart to impaired mitochondrial function, overproduction of ROS, enhanced cell death, and cardiac dysfunction, following pressure overload.
Estimating gear efficiency in a combined acoustic and trawl survey, with reference to the spatial distribution of demersal fish
Authors: Doray Mathieu , Mahévas Stéphanie , Trenkel Verena M. 
Published: December 2009

Abstract
Doray, M., Mahévas, S., and Trenkel, V. M. 2010. Estimating gear efficiency in a combined acoustic and trawl survey, with reference to the spatial distribution of demersal fish. – ICES Journal of Marine Science, 67: 668–676. Few analyses have been performed to estimate the efficiency of trawls targeting demersal fish using the ratio of catches and acoustic densities. In summer 2006, acoustic and fishing data were collected simultaneously over 3 d by three fishing vessels equipped with identical pelagic trawls in the Bay of Biscay. Variography identified moderate spatial autocorrelation in the acoustic backscatter at a mean scale of 3 km, a scale slightly smaller than the mean haul length (3.5 km), indicating that fish horizontal availability did not influence trawl efficiency. Acoustic backscattering densities expressed as nautical area scattering coefficients (NASCs) recorded in the trawled layer were compared with equivalent NASC (ENASC) values calculated from the species composition in the trawl, fish-length structure, and available relationships between target strength and fish length. Estimates of trawl efficiency for hake-dominated trawls were computed as the slopes of the relationships ENASC = 0.008 NASC and ENASC = 0.18 NASC0.31 for trawls made by day and night, respectively. For the whole demersal community, the relationships were ENASC = 0.022 NASC and ENASC = 0.17 NASC0.33 for trawls made by day and night, respectively.
Anaesthesia for proximal femoral fracture in the UK: first report from the NHS Hip Fracture Anaesthesia Network*
Authors: White S. M. , Griffiths R. , Holloway J. , Shannon A. 
Published: December 2009

SummaryThe aim of this audit was to investigate process, personnel and anaesthetic factors in relation to mortality among patients with proximal femoral fractures. A questionnaire was used to record standardised data about 1195 patients with proximal femoral fracture admitted to 22 hospitals contributing to the Hip Fracture Anaesthesia Network over a 2‐month winter period. Patients were demographically similar between hospitals (mean age 81 years, 73% female, median ASA grade 3). However, there was wide variation in time from admission to operation (24–108 h) and 30‐day postoperative mortality (2–25%). Fifty percent of hospitals had a mean admission to operation time < 48 h. Forty‐two percent of operations were delayed: 51% for organisational; 44% for medical; and 4% for ‘anaesthetic’ reasons. Regional anaesthesia was administered to 49% of patients (by hospital, range = 0–82%), 51% received general anaesthesia and 19% of patients received peripheral nerve blockade. Consultants administered 61% of anaesthetics (17–100%). Wide national variations in current management of patients sustaining proximal femoral fracture reflect a lack of research evidence on which to base best practice guidance. Collaborative audits such as this provide a robust method of collecting such evidence.