bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonality research: the state of the art
Authors: Koenig‐Lewis Nicole , Bischoff Eberhard E. 
Published: December 2005

AbstractThe paper reviews progress in the area of tourism seasonality research and is intended as a guide to the literature. The emphasis is on recent advances in this field. Amongst the various aspects considered are the definitions of seasonality, its causes and impacts, policy‐related issues, studies into consumer behaviour and approaches to measuring seasonality. The paper concludes that considerable gaps still exist in published research in this area and it argues that the field lacks a sound theoretical framework. It also suggests that adopting a more exacting quantitative perspective might facilitate and accelerate progress. Copyright © 2005 John Wiley & Sons, Ltd.
An analysis of the environmental reporting structures of selected European airlines
Authors: Chan Wilco W. , Mak Barry 
Published: December 2005

AbstractThis article draws on a survey of eight Europe based airlines' environmental reports to illustrate the status and progress of environmental reporting in the airline industry in Europe. Four major categories of components in the report are differentiated, namely recognised core components, recognised important components, recognised add‐on components and recognised developing components. The study further finds that the units used in the fuel efficiency indicator are not the same in the airlines studied and therefore benchmarking is difficult. The results also indicate that the topics pertinent to employee and community involvement exceed the technical data of discharge and compliance‐based environmental performance in their environmental policy statements. In addition, some new features of environmental reporting are identified. Copyright © 2005 John Wiley & Sons, Ltd.
Fixed tree games with multilocated players
Authors: Miquel S. , van Velzen B. , Hamers H. , Norde H. 
Published: December 2005

AbstractThis article introduces fixed tree games with multilocated players (FMP games), which are a generalization of standard fixed tree games. This generalization consists of allowing players to be located in more than one vertex. As a consequence, these players can choose among several ways of connection to the root. In this article we show that FMP games are balanced. Moreover, we prove that the core of an FMP game coincides with the core of a related submodular standard fixed tree game. We show how to find the nucleolus and we characterize the orders that provide marginal vectors in the core of an FMP game. Finally, we study the Shapley value and the average of the extreme points of the core. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 47(2), 93–101 2006
The multiroute maximum flow problem revisited
Authors: Du Donglei , Chandrasekaran R. 
Published: December 2005

AbstractWe are given a directed network G = (V,A,u) with vertex set V, arc set A, a source vertex s ∈ V, a destination vertex t ∈ V, a finite capacity vector u = {uij}(i,j)∈A, and a positive integer m ∈ Z+. The multiroute maximum flow problem (m‐MFP) generalizes the ordinary maximum flow problem by seeking a maximum flow from s to t subject to not only the regular flow conservation constraints at the vertices (except s and t) and the flow capacity constraints at the arcs, but also the extra constraints that any flow must be routed along m arc‐disjoint s‐t paths. In this article, we devise two new combinatorial algorithms for m‐MFP. One is based on Newton's method and another is based on an augmenting‐path technique. We also show how the Newton‐based algorithm unifies two existing algorithms, and how the augmenting‐path algorithm is strongly polynomial for case m = 2. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 47(2), 81–92 2006
Incidence of catheter‐related infections within 30 days from insertion of Hickman–Broviac catheters
Authors: Castagnola Elio , Molinari Angelo Claudio , Giacchino Mareva , Chiapello Nadia , Moroni Cristina , Caviglia Ilaria , Fratino Giuseppe , Haupt Riccardo 
Published: December 2005

AbstractAimTo evaluate the incidence of surgical site infections and bacteremias occurring within 30 days from insertion of partially implanted central venous catheters.Patients and MethodsFour hundred eighteen devices positioned in children with cancer or undergoing bone marrow transplant were followed prospectively.ResultsDuring a follow‐up of 12,394 catheter‐days, a total of 13 infectious episodes were documented, with an overall incidence of 3.1% and 1.05 episodes/1,000 catheter‐days. Coagulase‐negative staphylococci represented the causative pathogens of all episodes. Overall, surgical wound infections occurred in 1.4% of all catheters, with a rate of 0.48/1,000 catheter‐days, while isolated bacteremias were observed in 1.7% of all inserted devices, with a rate of 0.57/1,000 catheter‐days.ConclusionsInfections are rare events within 30 days from insertion of partially implanted central venous catheters and coagulase‐negative staphylococci represent the most frequently isolated cause of these complications. Pediatr Blood Cancer 2007;48:35–38. © 2005 Wiley‐Liss, Inc.
Low efficacy of methotrexate in childhood acute myeloid leukemia (AML): Single‐agent therapeutic window study in relapsed AML
Authors: Kaspers G.J.L. , Reinhardt D. , Fleischhack G. , Armendariz H. , Stark B. , Zwaan C.M. , Zimmermann M. , Creutzig U. 
Published: December 2005

AbstractBackgroundThe efficacy in pediatric acute myeloid leukemia (AML) of single‐agent methotrexate (MTX) at a higher dose than previously applied, 1,000 mg/m2, given as a theoretically beneficial 36‐hr continuous infusion, is unknown, but may be beneficial based on preclinical data.ProcedureWe performed a therapeutic window study in children with first relapsed AML treated in four different countries.ResultsBased on a comparison between the percentage of leukemic blasts in the bone marrow shortly before and 7–10 days after the MTX infusion, none of the first cohort of nine patients showed a good response, defined as a reduction of blasts of at least 50%. Therefore, the study was closed, concluding that the probability of a good response in this patient‐group was most likely to be less than 30%. By that time, another four patients had been enrolled, of which one patient with a late relapsed AML FAB type M7 showed a good response. Toxicity of MTX was limited and tolerable.ConclusionsThis study shows that single‐agent MTX in the applied regimen in pediatric relapsed AML has limited efficacy. However, it also demonstrates the feasibility of an international and therapeutic window phase II study in pediatric relapsed AML. Pediatr Blood Cancer 2006; 47:539–542. © 2005 Wiley‐Liss, Inc.
Synthesis and thermoresponsive property of end‐functionalized poly(N‐isopropylacrylamide) with pyrenyl group
Authors: Duan Qian , Miura Yutaka , Narumi Atsushi , Shen Xiande , Sato Shin‐Ichiro , Satoh Toshifumi , Kakuchi Toyoji 
Published: December 2005

AbstractN–Isopropylacrylamide (NIPAM) was polymerized using 1‐pyrenyl 2‐chloropropionate (PyCP) as the initiator and CuCl/tris[2‐(dimethylamino)ethyl]amine (Me6TREN) as the catalyst system. The polymerizations were performed using the feed ratio of [NIPAM]0/[PyCP]0/[CuCl]0/[Me6TREN]0 = 50/1/1/1 in DMF/water of 13/2 at 20 °C to afford an end‐functionalized poly(N‐isopropylacrylamide) with the pyrenyl group (Py–PNIPAM). The characterization of the Py–PNIPAM using matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry provided the number–average molecular weight (Mn,MS). The lower critical solution temperature (LCST) for the liquid–solid phase transition was 21.7, 24.8, 26.5, and 29.3 °C for the Py–PNIPAMs with the Mn,MS's of 3000, 3400, 4200, and 5000, respectively; hence, the LCST was dramatically lowered with the decreasing Mn,MS. The aqueous Py–PNIPAM solution below the LCST was characterized using a static laser light scattering (SLS) measurement to determine its molar mass, Mw,SLS. The aqueous solutions of the Py–PNIPAMs with the Mn,MS's of 3000, 3400, 4200, and 5000 showed the Mw,SLS of 586,000, 386,000, 223,000, and 170,000, respectively. Thus, lowering the LCST for Py–PNIPAM should be attributable to the formation of the PNIPAM aggregates. The LCST of 21.7 °C for Py–PNIPAM with the Mn,MS of 3000 was effectively raised by adding β‐cyclodextrin (β‐CD) and reached the constant value of ∼26 °C above the molar ratio of [β‐CD]/[Py–PNIPAM] = 2/1, suggesting that β‐CD formed an inclusion complex with pyrene in the chain‐end to disturb the formation of PNIPAM aggregates, thus raising the LCST. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1117–1124, 2006
Low potential electrosyntheses of free‐standing poly(dibenzofuran) films in mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid
Authors: Xu Jingkun , Zhou Weiqiang , Chen Bing , Pu Shouzhi , Wang Jingwu , Wan Yiqun 
Published: December 2005

AbstractFree‐standing poly(dibenzofuran) (PDBF) films were synthesized electrochemically by direct anodic oxidation of dibenzofuran in mixed electrolytes of boron trifluoride diethyl etherate (BFEE) containing certain amount of trifluoroacetic acid (TFA). The oxidation potential of dibenzofuran in pure BFEE was measured to be only 1.31 V versus saturated calomel electrode (SCE). This value was much lower than that determined in acetonitrile + 0.1 mol L−1 TBATFB (2.14 V vs. SCE). The addition of TFA to BFEE can further decrease the oxidation potential of the monomer to 1.07 V versus SCE in the mixed electrolyte of BFEE + 30% TFA. PDBF films obtained from this medium showed good electrochemical behavior, good electrochromic properties, and good thermal stability with conductivity of 100 S cm−1. FTIR and 1H NMR spectra showed that the polymer was grown mainly via the coupling of the monomer at C(3) C(10) or C(4) C(9) positions (Scheme 1). As‐formed PDBF films were partly soluble in tetrahydrofuran (THF) or chloroform. Fluorescent spectral studies indicated that either soluble or PDBF in solid state was a good blue light PDBF emitter. To the best of our knowledge, this is the first report that free‐standing PDBF films can be electrodeposited. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1125–1135, 2006
Monoaryloxo ytterbium(III) chlorides supported by β‐diketiminato ligands as novel initiators for the living ring‐opening polymerization of ε‐caprolactone
Authors: Xue Mingqiang , Sun Hongmei , Zhou Hui , Yao Yingming , Shen Qi , Zhang Yong 
Published: December 2005

AbstractRing‐opening polymerization of ε‐caprolactone (ε‐CL) was carried out using β‐diketiminato‐supported monoaryloxo ytterbium chlorides L1Yb(OAr)Cl(THF) (1) [L1 = N,N′‐bis(2,6‐dimethylphenyl)‐2,4‐pentanediiminato, OAr = 2,6‐di‐tert‐butylphenoxo‐], and L2Yb(OAr′)Cl(THF) (2) [L2 = N,N′‐bis(2,6‐diisopropylphenyl)‐2,4‐pentanediiminato, OAr′ = 2,6‐di‐tert‐butyl‐4‐methylphenoxo‐], respectively, as single‐component initiator. The influence of reaction conditions, such as polymerization temperature, polymerization time, initiator, and initiator concentration, on the monomer conversion, molecular weight, and molecular weight distribution of the resulting polymers was investigated. Complex 1 was well characterized and its crystal structure was determined. Some features and kinetic behaviors of the CL polymerization initiated by these two complexes were studied. The polymerization rate is first order with respect to monomer. The Mn of the polymer increases linearly with the increase of the polymer yield, while polydispersity remained narrow and unchanged throughout the polymerization in a broad range of temperatures from 0 to 50 °C. The results indicated that the present system has a “living character”. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1147–1152, 2006
Surface‐initiated atom transfer radical polymerization grafting of poly(2,2,2‐trifluoroethyl methacrylate) from flat silicon wafer surfaces
Authors: Chen Renxu , Feng Wei , Zhu Shiping , Botton Gianluigi , Ong Beng , Wu Yiliang 
Published: December 2005

AbstractPoly(2,2,2‐trifluoroethyl methacrylate) (PTFEMA), a partially fluorinated polymer, was directly grafted from silicon wafer surfaces by a surface‐initiated atom‐transfer radical polymerization (ATRP). The polymer layer thickness increased linearly with monomer conversion and molecular weight of free polymers in solution. The thickness was mainly determined by the experimental conditions such as activator/deactivator ratio, monomer/catalyst ratio, and monomer concentration. PTFEMA layers of more than 100‐nm thick were obtained. The grafted PTFEMA chains were “living” and allowed the extension of a second block of PMMA. X‐ray photoelectron spectroscopy study showed that the chemical compositions at the surfaces agreed well with their theoretical values. A novel surface‐attachable difunctional initiator was also synthesized and applied to the grafting of PTFEMA. The grafting density was doubled using this difunctional initiator, from 0.48 to 0.86 chains/nm2. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1252–1262, 2006
Quinone transfer radical polymerization of styrene: Synthesis of the actual initiator
Authors: Debuigne Antoine , Caille Jean‐Raphaël , Jérôme Robert 
Published: December 2005

Abstractortho‐Quinones, such as phenanthrenequinone and 3,6‐dimethoxyphenanthrenequinone, added with a catalytic amount of metal complexes, impart control to styrene polymerization via the previously reported quinone transfer radical polymerization (QTRP) process. In this study, compounds that mimic the dormant species proposed in the QTRP mechanism have been synthesized and tested as initiators in the presence of cobalt(II) acetylacetonate. These compounds, and particularly 3,6‐dimethoxy‐10‐hydroxy‐10‐(1‐phenyl‐ethyl)‐phenanthren‐9‐one, are effective control agents for the radical polymerization of styrene, in agreement with the recently proposed mechanism. Moreover, the induction period, which has been systematically reported in the presence of ortho‐quinones, is no longer observed. The end capping of the polystyrene chains by the control agent has been confirmed by 1H NMR analysis. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1233–1244, 2006
Synthesis and micellization of amphiphilic poly(sebacic anhydride)–poly(ethylene glycol)–poly(sebacic anhydride) block copolymers
Authors: Zhang Na , Guo Sheng‐Rong 
Published: December 2005

AbstractAmphiphilic biodegradable block copolymers [poly(sebacic anhydride)–poly(ethylene glycol)–poly(sebacic anhydride)] were synthesized by the melt polycondensation of poly(ethylene glycol) and sebacic anhydride prepolymers. The chemical structure, crystalline nature, and phase behavior of the resulting copolymers were characterized with 1H NMR, Fourier transform infrared, gel permeation chromatography, and differential scanning calorimetry. Microphase separation of the copolymers occurred, and the crystallinity of the poly(sebacic anhydride) (PSA) blocks diminished when the sebacic anhydride unit content in the copolymer was only 21.6%. 1H NMR spectra carried out in CDCl3 and D2O were used to demonstrate the existence of hydrophobic PSA domains as the core of the micelle. In aqueous media, the copolymers formed micelles after precipitation from water‐miscible solvents. The effects on the micelle sizes due to the micelle preparation conditions, such as the organic phase, dropping rate of the polymer organic solution into the aqueous phase, and copolymer concentrations in the organic phase, were studied. There was an increase in the micelle size as the molecular weight of the PSA block was increased. The diameters of the copolymer micelles were also found to increase as the concentration of the copolymer dissolved in the organic phase was increased, and the dependence of the micelle diameters on the concentration of the copolymer varied with the copolymer composition. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1271–1278, 2006
Sulfonated poly(ether ether ketone)/poly(vinylpyrrolidone) acid–base polymer blends for direct methanol fuel cell application
Authors: Wu Han‐Lang , Ma Chen‐Chi M. , Kuan Hsu‐Chiang , Wang Chung‐Hao , Chen Chih‐Yuan , Chiang Chin‐Lung 
Published: December 2005

AbstractAcid–base polymer blends for polymer electrolyte membranes have been prepared by blending sulfonated poly(ether ether ketone) (SPEEK) with poly(vinylpyrrolidone) (PVP) to reduce methanol uptake and to decrease methanol permeability while maintaining high proton conductivity. The acid‐base interaction occurring on the sulfonic acid group and on the tertiary amide group was characterized by FTIR and DMA. As the composition of PVP lowered than 20 wt % in the blends, the acid–base interaction causes great reduction on methanol uptake and the methanol permeability; however, the proton conductivity is still high. In this work, membrane–electrode assemblies (MEAs) have been prepared for direct methanol fuel cell (DMFC) from both blend membrane and Nafion 117. DMFC single cell performance was also evaluated. Results confirmed that SPEEK (with the degree of sulfonation (DS) = 69%) blended with PVP (Mn = 1,300,000) with a ratio of 80/20 (w/w) exhibits higher open‐circuit voltages (OCV) and lower polarization loss than those of Nafion 117. These acid–base blends will be suitable for DMFC application. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 565–572, 2006
PII structure in the model peptides for unfolded proteins: Studies on ubiquitin fragments and several alanine‐rich peptides containing QQQ, SSS, FFF, and VVV
Authors: Shi Zhengshuang , Chen Kang , Liu Zhigang , Sosnick Tobin R. , Kallenbach Neville R. 
Published: December 2005

AbstractA great deal of attention has been paid lately to the structures in unfolded proteins due to the recent discovery of many biologically functional but natively unfolded proteins and the far‐reaching implications of order in unfolded states for protein folding. Recently, studies on oligo‐Ala, oligo‐Lys, oligo‐Asp, and oligo‐Glu, as well as oligo‐Pro, have indicated that the left‐handed polyproline II (PII) is the major local structure in these short peptides. Here, we show by NMR and CD studies that ubiquitin fragments, model unfolded peptides composed of nonrepeating amino acids, and four alanine‐rich peptides containing QQQ, SSS, FFF, and VVV sequences are all present in aqueous solution predominantly in the extended PII or β conformation. The results from this and related studies indicate that PII might be a major backbone conformation in unfolded proteins. The presence of defined local backbone structure in unfolded proteins is inconsistent with predictions from random coil models. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Binding site‐based classification of coronaviral papain‐like proteases
Authors: Sulea Traian , Lindner Holger A. , Purisima Enrico O. , Ménard Robert 
Published: December 2005

AbstractThe coronavirus replicase gene encodes one or two papain‐like proteases (termed PL1pro and PL2pro) implicated in the N‐terminal processing of the replicase polyprotein and thus contributing to the formation of the viral replicase complex that mediates genome replication. Using consensus fold recognition with the 3D‐JURY meta‐predictor followed by model building and refinement, we developed a structural model for the single PLpro present in the severe acute respiratory syndrome coronavirus (SCoV) genome, based on significant structural relationships to the catalytic core domain of HAUSP, a ubiquitin‐specific protease (USP). By combining the SCoV PLpro model with comparative sequence analyses we show that all currently known coronaviral PLpros can be classified into two groups according to their binding site architectures. One group includes all PL2pros and some of the PL1pros, which are characterized by a restricted USP‐like binding site. This group is designated the R‐group. The remaining PL1pros from some of the coronaviruses form the other group, featuring a more open papain‐like binding site, and is referred to as the O‐group. This two‐group, binding site‐based classification is consistent with experimental data accumulated to date for the specificity of PLpro‐mediated polyprotein processing and PLpro inhibition. It also provides an independent evaluation of the similarity‐based annotation of PLpro‐mediated cleavage sites, as well as a basis for comparison with previous groupings based on phylogenetic analyses. Proteins 2006.
Insights on HIV‐1 Tat:P/CAF bromodomain molecular recognition from in vivo experiments and molecular dynamics simulations
Authors: Pantano Sergio , Marcello Alessandro , Ferrari Aldo , Gaudiosi Daniele , Sabò Arianna , Pellegrini Vittorio , Beltram Fabio , Giacca Mauro , Carloni Paolo 
Published: December 2005

AbstractStructural and functional studies indicate that, through its bromodomain, the cellular acetyltransferase P/CAF binds the acetylated Tat protein of human immunodeficiency virus type 1 (HIV‐1) and promotes transcriptional activation of the integrated provirus. Based on the NMR structure of P/CAF complexed with an acetylated Tat peptide, here we use molecular dynamics simulations to construct a model describing the interaction between full length Tat and the P/CAF bromodomain. Our calculations show that the protein–protein interface involves hydrophobic interactions between the P/CAF ZA loop and the Tat core domain. In particular, tyrosines 760 and 761 of P/CAF, two residues that are highly conserved in most known bromodomains, play an essential role for the binding. Fluorescence resonance energy transfer (FRET) experiments performed in this work demonstrate that P/CAF proteins in which these tyrosines are mutated into hydrophilic residues neither bind to Tat inside the cells nor mediate Tat transactivation. The combination of theoretical and in vivo studies provides new insights into the specificity of bromodomain recognition. Proteins 2006. © 2005 Wiley‐Liss, Inc.
The role of backbone stability near Ala44 in the high reduction potential class of rubredoxins
Authors: Tan Ming‐Liang , Kang ChulHee , Ichiye Toshiko 
Published: December 2005

AbstractRubredoxins may be separated into high and low reduction potential classes, with reduction potentials differing by ∼50 mV. Our previous work showed that a local shift in the polar backbone due to an A44 versus V44 side‐chain size causes this reduction potential difference. However, this work also indicated that in the low potential Clostridium pasteurianum (Cp) rubredoxin, a V44 → A44 mutation causes larger local backbone flexibility, because the V44 side‐chain present in the wild‐type (wt) is no longer present to interlock with neighboring residues to stabilize the subsequent G45. Since Pyrococcus furiosus (Pf) and other high potential rubredoxins generally have a P45, it was presumed that a G45 → P45 mutation might stabilize a V44 → A44 mutation in Cp rubredoxin. Here crystal structure analysis, energy minimization, and molecular dynamics (MD) were performed for wt V44G45, single mutant A44G45 and double mutant A44P45 Cp, and for wt A44P45 Pf rubredoxins. The local structural, dynamical, and electrostatic properties of Cp gradually approach wt Pf in the order wt Cp to single to double mutant because of greater sequence similarity, as expected. The double mutant A44P45 Cp exhibits increased backbone stability near residue 44 and thus enhances the probability that the backbone dipoles point toward the redox site, which favors an increase in the electrostatic contribution to the reduction potential. It appears that the electrostatic potential of residue 44 and the solvent accessibility to the redox are both determinants for the reduction potentials of homologous rubredoxins. Overall, these results indicate that an A44 in a rubredoxin may require a P45 for backbone stability whereas a V44 can accommodate a G45, since the valine side‐chain can interlock with its neighbors. Proteins 2006. © 2005 Wiley‐Liss, Inc.