bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oligomers and Polymers Based on Bridged Phenylenes as Electronic Materials
Authors: Grimsdale Andrew C. , Müllen Klaus 
Published: August 2007

AbstractThe synthesis, properties, and application in electronic devices of ladder and step‐ladder phenylene‐based oligomers and polymers are reviewed with an emphasis on control of properties by synthetic design. Bridged polyphenylenes can be prepared with a range of different amounts and types of bridges. Fully bridged polymers suffer the problem of incomplete formation of bridges during polymer analogous reactions. This problem is surmounted by the synthesis of regular stepladder polymers in which the monomers are well‐characterized oligo(ladder‐phenylene)s. By controlling the degree of bridging and thus the planarity of the polymer, its optical properties can be tuned. The optical and electronic properties can be further controlled by means of the type of bridges used.magnified image
Cationic Polymerization of Poly(vinyl ether) Bearing a TEMPO Radical: A New Cathode‐Active Material for Organic Radical Batteries
Authors: Suguro Masahiro , Iwasa Shigeyuki , Kusachi Yuki , Morioka Yukiko , Nakahara Kentaro 
Published: August 2007

AbstractPTVE was synthesized as a new active material for organic radical batteries. Cationic polymerization of a monomer bearing a TEMPO radical moiety took place. The spin concentration of PTVE was estimated to be 2.75 × 1021 spins · g−1 (100% spin per repeating unit). The PTVE is extremely stable; there is no decrease in spin concentration when storing PTVE samples for more than a year under aerobic conditions at room temperature. The redox potential of PTVE is 3.55 V (vs. Li/Li+). A coin‐type cell using a PTVE/VGCF composite electrode was also fabricated, and then performed charge/discharge measurements. The discharge capacity of PTVE is 114 mAh · g−1 (84% of the theoretical value).magnified image
Exploring Polymers of Intrinsic Microporosity – Microporous, Soluble Polyamide and Polyimide
Authors: Weber Jens , Su Qi , Antonietti Markus , Thomas Arne 
Published: August 2007

AbstractPolyamides and polyimides featuring a spirobifluorene unit as a structure directing motif in the polymer chain show intrinsic microporosity and consequently high surface areas. Such a spirobifluorene generates a 90° kink per repeating unit and thus prevents space‐efficient packing or crystallization of the otherwise stiff polymer chains. Thus, the approach presented here extends the concept of polymers of intrinsic microporosity for ladder type poly(dibenzodioxane)s to more common polymers of high commercial interest. For example, a microporous polyimide with a surface area of ≈550 m2 · g−1 was produced, which is readily soluble in chloroform.magnified image
The Effect of Substrate on the Annealing of Poly(butylene succinate) Single Crystals
Authors: Wang Xiaohong , Zhou Jianjun , Li Lin , Chan Chi‐Ming 
Published: August 2007

AbstractThe morphological evolution of poly(butylene succinate) (PBS) solution‐grown single crystals during annealing was studied using hot‐stage atomic force microscopy. Their morphology changed with increasing temperature and annealing time. The annealing behavior and melting temperature were found to be affected by the substrate. Morphological changes occurred at a much lower temperature on an amorphous carbon film than that on a mica surface. Moreover, the pattern of morphological evolution of the single crystals on a carbon film was different from that on a mica surface. Since the PBS melt had a larger contact angle on the mica surface, these differences in the melting behavior were ascribed to the different interfacial interactions between the chain‐folded surface of the single crystal and the substrate.magnified image
Metal Coordination and Aggregation Properties of Chiral Polythiophenes and Polythienylethynylenes
Authors: Matthews James R. , Goldoni Francesca , Kooijman Huub , Spek Anthony L. , Schenning Albertus P. H. J. , Meijer E. W. 
Published: August 2007

AbstractA series of chiral thio‐ and oxo‐substituted polythiophenes and polythienylethynylenes has been synthesised and investigated. The replacement of an oxo‐linkage by a thio‐linkage distorts and/or inhibits the helical aggregation behaviour. The quenching of fluorescence upon coordination to palladium is also radically different depending on the presence of oxo‐ or thio‐substitution of the thiophene units. The alkylthio‐substituted polythiophenes and polythienylethynylenes do act as sensors for palladium by quenching of their fluorescence to a significantly greater extent than the quenching observed for nonthio functionalised polythiophenes and polythienylethynylenes.magnified image
Shielding Effects in Polymer‐Polymer Reactions, 1
Authors: Fröhlich Markus G. , Vana Philipp , Zifferer Gerhard 
Published: August 2007

AbstractShielding effects of the surrounding arms and chains on the reactive centers taking part in RAFT four‐arm star polymerization following the Z‐group approach are calculated by means of exact enumeration of star/chain samples prepared by Monte Carlo techniques. The shielding effect, which can be relieved when using expanded core moieties, increases with increasing chain (arm) lengths. This leads to a reduction of the contact probability according to a power law with an exponent of −0.4 to −0.45. Additionally, characteristic chain properties and shape parameters are calculated as a function of the distance between the center of the star and the end of the linear chain in order to gain deeper insight into the mechanism of contact formation preceding the actual reaction.magnified image
Dynamic competition in pharmaceuticals: cross‐national evidence from new drug diffusion
Authors: Berndt Ernst R. , Danzon Patricia M. , Kruse Gregory B. 
Published: August 2007

AbstractWe report on an exploratory examination of the extent of differences across fifteen countries and three therapeutic classes (antihypertensives, antidepressants and antiepileptics) in the rate at which medicines in general and new medicines in particular are promoted and then diffuse, as well as relative new/old drug prices. We find substantial heterogeneity across classes and countries in promotion and diffusion. In terms of diffusion, relative prices of old vs. new drugs, and intensity of detailing physicians, we find that somewhat surprisingly, the US is often “in the middle” relative to other countries, and is not an outlier. However, differences across classes are striking. Overall, new drug quantity elasticities with respect to own price are negative, ranging from about −0.75 to −1.1, while cross‐price (new drug quantity with respect to old drug price) are positive but small. Total promotion effects on total utilization are generally positive, particularly antidepressants. Promotion of new drugs positively affects the new drug share, while promotion of old drugs negatively affects the new drug share. Promotion of old drugs is surprisingly substantial in some classes and countries. Copyright © 2007 John Wiley & Sons, Ltd.
‘Branded Generics’ as a strategy to limit cannibalization of pharmaceutical markets
Authors: Reiffen David , Ward Michael R. 
Published: August 2007

AbstractThis paper demonstrates how, by introducing a generic version of its previously patented product, a branded firm can influence the equilibrium in the generic segment of the market for the product. This in turn can increase the firm's profits from selling the branded version. We then use structural estimates from previous literature to calculate the magnitude of the effects in the generic and branded segments. Copyright © 2007 John Wiley & Sons, Ltd.
Determinants of drug prices and expenditures
Authors: Comanor William S. , Schweitzer Stuart O. 
Published: August 2007

AbstractThe process by which pharmaceuticals are bought and sold is exceedingly complex. The major reason is that most consumers do not pay directly for the drugs they consume. Intermediaries are generally present who purchase pharmaceuticals from their manufacturers and have them provided to their subscribers or affiliates. The products themselves, however, are generally supplied by the same pharmacies used by cash purchasers. The purpose of this paper is to describe and examine these markets. Copyright © 2007 John Wiley & Sons, Ltd.
An industrial organization perspective on the influenza vaccine shortage
Authors: Scherer F.M. 
Published: August 2007

AbstractThis paper analyzes reasons advanced for the recent shortage of influenza vaccine in the United States and numerous other similar shortages in recent years. Explanations have included high regulatory costs, inadequate profitability, and mergers. Using Census data, it shows that vaccine producers realize unusually high price‐cost margins, but are probably also unusually capital‐intensive. Applying theories of scale economies to existing information, it identifies the extent to which, for diverse types of vaccines, economies of scale limit the number of vaccine producers, exposing the nation to stochastic shortage risk. A benefit/cost analysis explores whether it is economically worthwhile to maintain additional production sources with surge capacity. It is found that under plausible demand, external benefit, and stochastic supply failure conditions, such multiple sourcing yields more benefits than its cost. Copyright © 2007 John Wiley & Sons, Ltd.
Product differentiation, competition and regulation of new drugs: the case of statins in four European countries
Authors: Kanavos Panos , Font Joan Costa , McGuire Alistair 
Published: August 2007

AbstractThis paper examines the determinants of competition in the statins market across four European countries over the 1991–2002 period. Using IMS data from the UK, Germany, France and the Netherlands, the paper analyses the potential existence of competition between branded statins prior to patent expiry. Against a conceptual background of Cournot type quantity competition with product differentiation a demand function is estimated using panel data analysis for the first and second entrants on the market. The results indicate substitutability across the initial market entrants and the subsequent entrant only. This is consistent with potential price sensitivity in the branded market for statins, even when the overall size of market is growing. The results are indicative due to empirical issues surrounding endogeniety of the price variable. Copyright © 2007 John Wiley & Sons, Ltd.
Microvascular breast reconstruction pedicle thrombosis: How long can we wait?
Authors: Vijan Sandeep S. , Tran Nho V. 
Published: August 2007

AbstractRe‐exploration plays a key role in salvaging vascularly compromised free flaps. A retrospective review of 290 free flaps in breast reconstruction was performed to determine whether the time delay between thrombosis detection and surgical re‐exploration had any effect on flap salvage. Overall flap success was 97.6%. Postoperative thrombosis requiring re‐exploration was documented in 6.2% cases. Fifty‐five percent of take‐back flaps were salvaged and 45% were lost. The median time between detection of flap compromise to surgical incision was 128 min in our saved flaps, and 228 min in the lost flap group. Our preliminary data suggests that re‐exploration within 188 min may improve flap salvage. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Concentration decrease of nitric oxide in the postischemic muscle is not only caused by the generation of O
Authors: Stoffels Felix , Lohöfener Felix , Beisenhirtz Moritz , Lisdat Fred , Büttemeyer Rolf 
Published: August 2007

AbstractReperfusion of ischemic skeletal muscle is associated with an alteration of the concentrations of O and NO. In this study, the influence of epigallocatechin‐3‐gallate (EGCG), a known radical scavenger, on the balance of O and NO has been measured online in the skeletal muscle of Wistar rats. The hind limb of 14 male rats had been exposed to ischemic stress for 2 h. Seven rats received an infusion of 1.5 μmol EGCG/kg 5 min before reperfusion. O, NO, and temperature were measured during reperfusion. The concentration of O declined under the influence of EGCG from 156.5 to 72.2 nmol/l (P = 0.01). The level of NO was found to decrease; this decrease was not significantly changed by EGCG (−175 nmol/l vs. – 227 nmol/l; P = 0.33). Thus the different superoxide concentrations did not correspond to different levels of NO, and the interaction of both radicals is not the only reason for the concentration decrease of NO in the reperfusion period. We conclude that EGCG protects skeletal muscle from I/R‐injury without influencing the NO concentration profile to a large extent. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Case ascertainment of alcohol dependence in general population surveys: ‘gated’ versus ‘ungated’ approaches
Authors: Degenhardt Louisa , Bohnert Kipling M. , Anthony James C. 
Published: August 2007

AbstractSocial role impairment and other forms of maladaptation are referenced explicitly in the case definitions for the drug use disorders within DSM‐IV‐TR, but there is continuing debate about whether and how to include these manifestations of ‘clinical significance’ in diagnostic criteria and assessment protocols. When a ‘gated’ approach (based on impairment or other maladaptation) has been taken during recent large scale psychiatric surveys with coverage of drug dependence (e.g. to reduce participant fatigue or burden), the net effect may include (a) a reduced number of identified cases, and (b) biases in the estimates of association linked to the occurrence of drug dependence. In this report focused on alcohol dependence, we probe these issues, making use of data from the cross‐sectional US National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a household survey with 44,093 adult participants. NESARC alcohol dependence assessments were ‘ungated’, but allowed simulation of a ‘gated’ approach; the end result was a robust decrement in the estimated prevalence of this condition. Nonetheless, patterns of association linking suspected background characteristics to prevalence of alcohol dependence were not appreciably different when the gated and ungated estimates were contrasted. In summary, there are reasons to take the ungated approach in detailed research on alcohol use and dependence. Nevertheless, in panoramic mental health surveys, the inefficiency of an ungated approach must be balanced against the anticipated yield of cases who have experienced alcohol dependence without alcohol related social role impairments or other maladaptation, particularly when the dependence syndromes without these consequences are sometimes thought to lack clinical significance. Copyright © 2007 John Wiley & Sons, Ltd.
Emulsifier‐Free Emulsion Copolymerization of Vinyl Acetate and 3‐Dimethyl(methacryloyloxyethyl)ammonium Propanesulfonate and Swelling Behavior of their Copolymer Matrices
Authors: Kamenska Elena , Kostova Bistra , Ivanov Ivo , Rachev Dimitar , Georgiev George 
Published: August 2007

AbstractStable poly{(vinyl acetate)‐co‐[3‐dimethyl(methacryloyloxyethyl)ammonium propanesulfonate]} latexes with different compositions were synthesized by emulsifier‐free emulsion copolymerization. An unusual “overshooting” behavior of the copolymer tablets is explained based on the formation of specific clusters of oppositely oriented dipoles. The variation of their concentration with the zwitterionic monomer unit fraction, ionic strength and temperature is responsible for the differences in the swelling kinetics established. The results show that these parameters can be used to control swelling degree of copolymer matrices and their sustained drug delivery.magnified image
SANISAND: Simple anisotropic sand plasticity model
Authors: Taiebat Mahdi , Dafalias Yannis F. 
Published: August 2007

AbstractSANISAND is the name used for a family of simple anisotropic sand constitutive models developed over the past few years within the framework of critical state soil mechanics and bounding surface plasticity. The existing SANISAND models use a narrow open cone‐type yield surface with apex at the origin obeying rotational hardening, which implies that only changes of the stress ratio can cause plastic deformations, while constant stress‐ratio loading induces only elastic response. In order to circumvent this limitation, the present member of the SANISAND family introduces a modified eight‐curve equation as the analytical description of a narrow but closed cone‐type yield surface that obeys rotational and isotropic hardening. This
modification enables the prediction of plastic strains during any type of constant stress‐ratio loading, a feature lacking from the previous SANISAND models, without losing their well‐established predictive capability for all other loading conditions including the cyclic. In the process the plausible assumption is made that the plastic strain rate decomposes in two parts, one due to the change of stress ratio and a second due to loading under constant stress ratio, with isotropic hardening depending on the volumetric component of the latter part only. The model formulation is presented firstly in the triaxial stress space and subsequently its multiaxial generalization is developed following systematically the steps of the triaxial one. A detailed calibration procedure for the model constants is presented, while successful simulation of both drained and undrained behavior of sands under constant and variable stress‐ratio loadings at various densities and confining pressures is obtained by the model. Copyright © 2007 John Wiley & Sons, Ltd.
A supply chain design model with unreliable supply
Authors: Qi Lian , Shen Zuo‐Jun Max 
Published: August 2007

AbstractUncertainties abound within a supply chain and have big impacts on its performance. We propose an integrated model for a three‐tiered supply chain network with one supplier, one or more facilities and retailers. This model takes into consideration the unreliable aspects of a supply chain. The properties of the optimal solution to the model are analyzed to reveal the impacts of supply uncertainty on supply chain design decisions. We also propose a general solution algorithm for this model. Computational experience is presented and discussed. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Campus cultural and artistic activity effects evaluation model: a study of universities in Taiwan
Authors: Wu Shwu‐Ing 
Published: August 2007

Abstract

This research examines three types of universities in Taiwan to discuss the factors that influence campus cultural and artistic activity effects and establishes a structure model. In this research, university students are the target group for nonprofit organizations (NPOs) that regard cultural and artistic activities as products or services. The study used message contact, emotion, cognition, message evaluation, and attitude toward the activity as the influence factors. The relationships among these factors along with student participatory intention, participation behavior, and activity effect were then explored. The results show that each influence factor affects student willingness to participate, which leads to different levels of participation and effectiveness. Moreover, there are hierarchical relationships between the influence factors and effects.

Copyright © 2007 John Wiley & Sons, Ltd.
Gift giving: an interdisciplinary review
Authors: Sargeant Adrian , Woodliffe Lucy 
Published: August 2007

Abstract

The issue of why individuals choose to support charity has been the focus of considerable research in the disciplines of economics, psychology, social psychology, sociology, anthropology and more recently, management and marketing. This paper draws together extant work, developing a content model of giving behavior that fundraisers may use to inform their professional practice. A number of specific propositions are developed from the literature to assist in this goal. The paper provides summary tables of existing empirical studies categorized by the dimensions of the model, explores ambiguity in research findings, and concludes by highlighting opportunities for further research

Copyright © 2007 John Wiley & Sons, Ltd.
In the frame: investigating the use of mobile phone photography in museums
Authors: Leighton Debra 
Published: August 2007

Abstract
The ubiquitous use of mobile phone technology to capture photographic images has rapidly become an accepted feature of our social and cultural lifestyle. From the capture of photographic images in a social setting to the evening news reports of the 7/7 suicide bombings that led with phone video footage taken by a member of the public, mobile phone photography has rapidly become embedded in everyday life and presents a new set of challenges for marketers in all sectors. Within the heritage sector, mobile phone photography presents new methods for visitors to interact with and interpret historic sites, buildings and artefacts. This paper explores the use of mobile phone photography within the museum setting through an empirical study conducted at the National Football Museum in Preston, UK. It discusses the role of mobile phone photography in the visitor experience, in formal and informal learning provision, in stimulating the motivation to learn and in encouraging social interaction with visitor groups. The paper concludes with the identification of potential marketing opportunities for the museum and wider heritage sector.

Copyright © 2007 John Wiley & Sons, Ltd.
Genome‐wide expression analysis of Middle Eastern papillary thyroid cancer reveals c‐MET as a novel target for cancer therapy
Authors: Siraj AK , Bavi P , Abubaker J , Jehan Z , Sultana M , Al‐Dayel F , Al‐Nuaim A , Alzahrani A , Ahmed M , Al‐Sanea O , Uddin S , Al‐Kuraya KS 
Published: August 2007

AbstractIn an attempt to find genes that may be of importance in malignant progression of papillary thyroid carcinoma (PTC) in the Middle East, which therefore can be targeted in cancer therapy, we screened and validated the global gene expression in PTC using cDNA expression arrays and immunohistochemistry (IHC) on tumour tissue microarrays. Twenty‐nine PTC tissue specimens were compared with seven non‐cancerous thyroid specimens by use of cDNA microarray. Results for selected genes were confirmed by quantitative real‐time PCR. Protein expression of selected genes was further studied using a tissue microarray consisting of 536 PTCs and compared with histologically non‐cancerous tissue samples. One hundred and ninety‐six genes were overexpressed in PTC tissues relative to non‐cancerous thyroid tissues. The genes that were up‐regulated in PTC were involved in cell cycle regulation, cell signaling, and oncogenesis. Among these genes, c‐MET was identified by immunohistochemical methods as a protein that is overexpressed in 37% of PTCs and was significantly associated with more aggressive behaviour, eg higher stage, nodal involvement, and tall cell variant (p value = 0.01, 0.01 and 0.04, respectively). In this study, 55% of the PTC cases expressed activated AKT (P‐AKT), which suggests that activated AKT may play an important role in PTC tumourigenesis. The fact that most of the PTC cases that had activated AKT showed overexpression of c‐MET (p = 0.027) leads us to hypothesize that c‐MET may be an alternative mechanism of AKT activation in Middle Eastern PTCs. Finally, our data suggest that c‐MET dysregulation is associated with aggressive behaviour and may serve as a molecular biomarker and potential therapeutic target in this disease. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.