bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Ag nanoparticles termini‐protected side‐chain liquid crystalline azobenzene polymers by RAFT polymerization
Authors: Gao Jiangang , Sun Youyi , Zhou Jingli , Zheng Zhi , Chen Hongwei , Su Wei , Zhang Qijin
Published: October 2007

A new synthetic approach to prepare Ag nanoparticles protected side‐chain liquid crystalline (LC) azobenzene polymers was reported. It is based on the reduction of silver ions in presence of a LC polymer polymerized by RAFT. The formation of Ag colloidal nanoparticles was confirmed by TEM and UV analysis. At the same time, according to the results of DSC, XPS, and FTIR spectra, Ag nanoparticles were protected by the side‐chain LC azobenzene polymers through surface attachment interactions between thiol groups and Ag. The out‐plane orientation of side‐chain LC is confirmed by surface‐enhanced Raman spectra analysis and scanning near‐field optical microscope, resulting from the large electromagnetic field arising from the excitation of surface plasmon polariton of Ag nanoparticles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5380–5386, 2007
Bulk polymerization of p‐dioxanone using a cyclic tin alkoxide as initiator
Authors: Redin Therese , Finne‐Wistrand Anna , Mathisen Torbjörn , Albertsson Ann‐Christine
Published: October 2007

Poly(p‐dioxanone) with an inherent viscosity of over 1 dL/g has been synthesized using the cyclic tin alkoxide 1‐di‐n‐butyl‐1‐stanna‐2,5‐dioxacyclopentane as initiator. Poly(p‐dioxanone) was synthesized in bulk and the results have been compared with polymerizations using tin (II) 2‐ethylhexanoate (Sn(Oct)2) as catalyst. Sn(Oct)2 has often been reported to be an effective catalyst for the synthesis of poly(p‐dioxanone), but here it is compared with an initiator which is less prone to catalyze transesterification reactions. The results demonstrate that the cyclic tin initiator is a promising alternative for the synthesis of poly(p‐dioxanone) with a high inherent viscosity. Poly(p‐dioxanone) is a polymer with mechanical properties and a degradation rate suitable for tissue engineering applications. Both the cyclic tin initiator and Sn(Oct)2 gave, under some reaction conditions, inherent viscosities around 1 dL/g. The best polymer synthesized using the cyclic tin initiator had a strain‐at‐break of 515% and a stress‐at‐break of 43 MPa. The inherent viscosity of this polymer was 1.16 dL/g, while Sn(Oct)2 resulted in a polymer with an inherent viscosity less than 0.4 dL/g under the same reaction conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5552–5558, 2007
Synthesis of star polymers via nitroxide mediated free‐radical polymerization: A “core‐first” approach using resorcinarene‐based alkoxyamine initiators
Authors: Abraham Sinoj , Choi Jae Ho , Ha Chang‐Sik , Kim Il
Published: October 2007

The synthesis of new octafunctional alkoxyamine initiators for nitroxide‐mediated radical polymerization (NMRP), by the derivatization of resorcinarene with nitroxide free radicals viz TEMPO and a freshly prepared phosphonylated nitroxide, is described. The efficiency of these initiators toward the controlled radical polymerization of styrene and tert‐butyl acrylate is investigated in detail. Linear analogues of these multifunctional initiators were also prepared to compare and evaluate their initiation efficiency. The favorable conditions for polymerization were optimized by varying the concentration of initiators and free nitroxides, reaction conditions, etc., to obtain well‐defined star polymers. Star polystyrene thus obtained were further used as macro‐initiator for the block copolymerization with tert‐butyl acrylate. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5559–5572, 2007
Chemical synthesis and electric properties of the conducting copolymer of aniline and o‐aminophenol
Authors: Zhang Jing , Shan Dan , Mu Shaolin
Published: October 2007

A copolymer, poly(aniline‐co‐o‐aminophenol), was prepared chemically by using ammonium peroxydisulfate as an oxidant. The monomer concentration ratio of o‐aminophenol to aniline strongly influences the copolymerization rate and properties of the copolymer. The optimum composition of a mixture for the chemical copolymerization consisted of 0.3 M aniline, 0.021 M o‐aminophenol, 0.42 M ammonium peroxydisulfate, and 2 M H2SO4. The result of cyclic voltammograms in a potential region of −0.20 to 0.80 V (vs.SCE) indicates that the electrochemical activity of the copolymer prepared under the optimum condition is similar to that of polyaniline in more acid solutions. However, the copolymer still holds the good electrochemical activity until pH 11.0. Therefore, the pH dependence of the electrochemical property of the copolymer is improved, compared with poly(aniline‐co‐o‐aminophenol) prepared electrochemically, and is much better than that of polyaniline. The spectra of IR and 1H NMR confirm that o‐aminophenol units are included in the copolymer chain, which play a key role in extending the usable pH region of the copolymer. The visible spectra of the copolymers show that a high concentration ratio of o‐aminophenol to aniline in a mixture inhibits the chain growth. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5573–5582, 2007
Morphology and permeability of exfoliated PVAc‐MMT nanocomposite films cast from soap‐free emulsion‐polymerized latices
Authors: Chien An‐Ting , Lin King‐Fu
Published: October 2007

In this study, we exclusively found that the exfoliated poly(vinyl acetate)‐montmorillonite (PVAc‐MMT) nanocomposite latices could be straightforwardly fabricated by soap‐free emulsion polymerization and cast into a film. The as‐fabricated films were transparent with the exfoliated MMT nanoplatelets in flat form uniformly dispersed in the PVAc matrix. Certain bonding of PVAc matrix to the exfoliated MMT nanoplatlets refrained it from removal by acetone in Soxhlet extraction. Exfoliated MMT nanoplatlets (10 wt %) in the film was able to reduce the water vapor permeability coefficient to only 9% that of the neat PVAc. According to the generalized Nielsen's permeability model for the composites containing impermeable fillers in sheet form, the average aspect ratio of exfoliated MMT platelets was calculated as 327, similar to those directly estimated by atomic force microscopy and transmission electron microscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5583–5589, 2007
Cyclic and multicyclic poly(ether sulfone)s by polycondensation of 5,5′,6,6′‐tetrahydroxy‐ 3,3,3′,3′‐tetramethyl spirobisindane and 4,4′‐difluorodiphenylsulfone
Authors: Kricheldorf Hans R. , Bornhorst Kirstin
Published: October 2007

5.5′,6,6′‐Tetrahydroxy‐3,3,3′,3′‐tetramethyl spirobisindane (TTSBI) was polycondensed with 4,4′‐difluorodiphenylsulfone (DFDPS) in DMSO with K2CO3 as catalyst and azeotopic removal of water. The feed ratio of DFDPS/TTSBI was varied from 1.0/1.0 to 2.0/1.0 at concentrations avoiding gelation. At feed ratios around 1.0/1.0 hyperbranched polymers were a minority and cyclic poly(ether sulfone)s were the predominant reaction products. With increasing feed ratio of DFDPS more and more multicyclic polymers were formed, and at a feed ratio of 1.9/1.0 perfect multicycles free of functional groups were the vast majority of the reaction product. Despite variation of the reaction conditions quantitative conversion was not achieved. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5597–5605, 2007
Synthesis and characterization of highly refractive polyimides from 4,4′‐thiobis[(p‐phenylenesulfanyl)aniline] and various aromatic tetracarboxylic dianhydrides
Authors: Liu Jin‐Gang , Nakamura Yasuhiro , Shibasaki Yuji , Ando Shinji , Ueda Mitsuru
Published: October 2007

An aromatic sulfur‐containing diamine 4,4′‐thiobis[(p‐phenylenesulfanyl) aniline] (3SDA) was synthesized and polymerized with a sulfur‐containing dianhydride 4,4′‐[p‐thiobis(phenylenesulfanyl)]diphthalic anhydride (3SDEA) and three nonsulfur aromatic tetracarboxylic dianhydrides, respectively to afford four poly(amic acid)s (PAAs) with the inherent viscosities of 0.54–1.04 dL/g. Flexible and tough polyimide (PI) films obtained from the PAA precursors showed good thermal, mechanical, and optical properties. The glass transition temperatures (Tgs) of the PIs ranged from 179.1–227.2 °C determined by differential scanning calorimetry (DSC), and 173.8–227.3 °C by dynamic mechanical analysis (DMA), depending on the dianhydride used. The 10% weight loss temperatures were in the range of 500–536 °C, showing high intrinsic thermal‐resistant characteristics of the PI films. The PI films also showed good optical transparency above 500 nm, which agreed well with the calculated absorption spectra using the time‐dependent density functional theory. The average refractive indices (nav) measured at 632.8 nm were 1.7191–1.7482, and the in‐plane/out‐of‐plane birefringences (Δn) were 0.0068–0.0123. The high refractive indices originate from the high sulfur contents, good molecular packing, and the absence of bulky structures. The relatively small birefringence mainly results from the flexible thioether linkages structures of the diamine. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5606–5617, 2007
RAFT polymerization of a novel activated ester monomer and conversion to a terpyridine‐containing homopolymer
Authors: Aamer Khaled A. , Tew Gregory N.
Published: October 2007

Developing new materials with unique properties for nanotechnology applications, in general, and supramolecular polymers, in particular, lie at the heart of much ongoing research. In line with these efforts, we have been exploring polymers containing terpyridine (terpy) in the side chain. Here we report a new monomer that effectively undergoes reversible addition fragmentation chain transfer polymerization (RAFT) to yield high‐molecular‐weight (Mn) polymers with narrow polydispersity (PDI). The monomer is an N‐succinimide activated ester of p‐vinyl benzoic acid. Under RAFT conditions, poly(N‐succinimide p‐vinylbenzoate)s were generated, with Mn ranging between 44 and 61 kDa and PDI of 1.03–1.07. One of these homopolymers was reacted with an amine functionalized terpy, creating a new homopolymer containing terpy ligands on every monomer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5618–5625, 2007
Homogeneous phase polymerization of vinylidene fluoride in supercritical carbon dioxide
Authors: Beuermann Sabine , Imran‐ul‐Haq Muhammad
Published: October 2007

For the first time, stabilizer‐free vinylidene fluoride (VDF) homopolymerizations were carried out in homogenous phase with supercritical CO2using the conventional initiator di‐tertbutyl peroxide (DTBP). In‐line FT‐NIR spectroscopy showed that complete monomer conversion may be obtained. Molecular weights were determined via size‐exclusion chromatography and polymer endgroup analysis by1H‐NMR spectroscopy. The number average molecular weights were below 104g mol−1and polydispersities ranged from 3.1 to 5.7 depending on DTBP and VDF concentration. For allowing isothermal reaction, high CO2contents ranging from 61 to 83 wt % were used. The high‐temperature and high‐pressure conditions required for homogeneous polymerization did not alter the amount of defects in VDF chaining. Scanning electron microscopy indicated that regular stack‐type particles are obtained upon expansion of the homogeneous polymerization mixture. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5626–5635, 2007
Synthesis and properties of an ionic polyacetylene with aromatic heterocycles
Authors: Gal Yeong‐Soon , Jin Sung‐Ho , Park Jong‐Wook
Published: October 2007

A new ionic polyacetylene with two aromatic heterocycles (pyridyl and thienyl) was prepared by the activation polymerization of 2‐ethynylpyridine by using 3‐(6‐bromohexyloxy)methylthiophene without any additional initiator or catalyst. The activated acetylenic triple bond of N‐substituted‐2‐ethynylpyridinium bromide, formed at first quaternarization process, was susceptible to linear polymerization. The instrumental analysis data on the polymer structure revealed that the polymer have the conjugated polyene backbone structure with the designed two aromatic heterocycles. The photoluminescence peak is located at 510 nm corresponding to a photon energy of 2.43eV. The electrochemical properties of this ionic polyacetylene were also measured and discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5679–5685, 2007
Rheological properties and crystallization behavior of multi‐walled carbon nanotube/poly(ε‐caprolactone) composites
Authors: Wu Defeng , Wu Liang , Sun Yurong , Zhang Ming
Published: October 2007

Multi‐walled carbon nanotube/poly(ε‐caprolactone) composites (PCLCNs) were prepared by melt compounding. The rheology, nonisothermal crystallization behavior, and thermal stability of PCLCNs were, respectively, investigated by the parallel‐plate rheometer, differential scanning calorimeter, and TGA. Cole–Cole plots were employed successfully to detect the rheological percolation of PCLCNs under small amplitude oscillatory shear. PCLCNs present a low percolation threshold of about 2–3 wt % in contrast to that of clay‐based nanocomposites. The percolated nanotube network is very sensitive to the steady shear deformation, and is also to the temperature, which makes the principle of time‐temperature superposition be invalid on those percolated PCLCNs. Small addition of nanotube cannot improve the thermal stability of PCL but can increase crystallization temperature remarkably due to the nucleating effect. As the nanotube is much enough to be percolated, however, the impeding effect becomes the dominant role on the crystallization, and the thermal stability increases to some extent. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3137–3147, 2007
Self‐decelerated crystallization in poly(butylene terephthalate)/poly(ε‐caprolactone) blends
Authors: Di Lorenzo Maria Laura , Righetti Maria Cristina
Published: October 2007

Isothermal crystallization of poly(butylene terephthalate) (PBT) blended with oligomeric poly(ε‐caprolactone) (PCL) is investigated by polarized optical microscopy and differential scanning calorimetry at various temperatures (Tc). The growth rate of PBT spherulites is found to depend on time (t), as the spherulite radius (r) linearly increases with t at the early stages of crystallization (r ∝ t), then, with the progress of phase transition, the spherulite radius becomes dependent on the square root of the time (r ∝ t1/2) until termination of crystal growth. The nonlinear advance of the crystal growth front is caused by a varied composition of the melt phase in contact with the growing crystals, due to diffusion of mobile PCL chains away from the spherulite surface. The melt phase becomes spatially inhomogeneous, causing self‐deceleration of PBT crystallization until a limit composition that prevents further crystallization is reached in the melt. The maximum crystallinity achievable during isothermal crystallization decreases with Tc. The lowering of the temperature after termination of the isothermal crystallization allows to complete the crystal growth, but the final developed crystallinity still depends on Tc, being lower at higher Tcs. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3148–3155, 2007
Effect of substituent polarity, bulk, and substitution site toward enhancing gas permeation in dibromohexafluorobisphenol‐a based polyarylates
Authors: Bhole Yogesh S. , Karadkar Prasad B. , Kharul Ulhas K.
Published: October 2007

The gas permeation properties of polyarylates were tuned by varying nature and site of substituents present on both of its monomers, viz., bisphenol and dicarboxylic acid. The phenyl rings of hexafluorobisphenol‐A were substituted in asymmetric manner by polar bromine to obtain dibromohexafluorobisphenol‐A. This bisphenol was polymerized with equimolar mixture of iso‐ and terephthalic acid (base case), bromo‐ and nitroterephthalic acid (polar group substituted acids), 4,4′‐hexafluoroisopropylidene bis(benzoic acid), and t‐butyl isophthalic acid (bulky group containing acids). Physical properties and gas permeation properties of these polyarylates were investigated to assess combined effects of asymmetric nature of bisphenol substitution, polar nature of substituent bromine, hexafluoroisopropylidene group present at the bridge position of bisphenol, and substituent present on the acid moiety. The combination of these substituent types led these polyarylates to lie near Robeson upper bound. The gas sorption analysis and estimation of diffusivity in these polyarylates shed a light on observed variations in gas permeation properties by attempted structural variations. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3156–3168, 2007
Volume changes under strain resulting from the incorporation of rubber granulates into a rubber matrix
Authors: Kumar P. , Fukahori Y. , Thomas A. G. , Busfield J. J. C.
Published: October 2007

The strength of an elastomer is in part determined by the size of the intrinsic flaws that are present. It has been observed that the incorporation of rubber granulates into a virgin matrix results in a reduction in strength and this has previously been attributed to an increase in the intrinsic flaw size. The precise nature of this intrinsic flaw is the subject of this investigation. Fundamental questions concerning the change in flaw size with strain and the reduction in strength resulting from a weaker interface have been investigated using volume change experiments. Initial experiments on carbon black filled rubber with no granulates incorporated have shown no significant volume change under strain. This contrasts with granulate filled materials whose experimentally measured volume changes with strain were seen to be substantially greater. Microstructural finite element analysis has revealed how this change in volume might result from a net increase in the flaw size with increasing strain. This work suggests that flaw size increases in a characteristic way with strain for materials where the matrix and granulates have a similar modulus, whereas a modulus mismatch between the matrix and the recycled granulate results in much larger volume changes and hence greater flaw size which also appears to increase with strain. This work emphasizes the importance in practical applications of matching the modulus of recycled granulate materials to that of the new virgin material in the matrix. This article introduces a novel technique for examining small changes in the interfacial bonding mechanisms under strain such as that caused by surface modification techniques. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3169–3180, 2007
Melt rheology of polylactide/montmorillonite nanocomposites
Authors: Gu Shu‐Ying , Ren Jie , Dong Bo
Published: October 2007

In this article, the linear and nonlinear shear rheological behaviors of polylactide (PLA)/clay (organophilic‐montmorillonite) nanocomposites (PLACNs) were investigated by an Advanced Rheology Expanded System rheometer. The nanocomposites were prepared by master batch method using a twin‐screw extruder with poly(ε‐caprolactone) (PCL) as a compatibilizer. The presence of org‐MMT leads to obvious pseudo‐solid‐like behaviors of nanocomposite melts. The behaviors caused by the formation of a “percolating network” derived from the reciprocity among the strong related sheet particles. Therefore, the storage moduli, loss moduli, and dynamic viscosities of PLACNs show a monotonic increase with MMT content. Nonterminal behaviors exists in PLACNs nanocomposites. Besides the PLACNs melts show a greater shear thinning tendency than pure PLA melt because of the preferential orientation of the MMT layers. Therefore, PLACNs have higher moduli but better processibility compared with pure PLA. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3189–3196, 2007
Thermal monitoring of morphology in triblock terpolymers with crystallizable blocks
Authors: Boschetti‐de‐Fierro Adriana , Fierro Daniel , Albuerne Julio , Funari Sérgio S. , Abetz Volker
Published: October 2007

The bulk morphology of poly(1,4‐butadiene)–block–polystyrene–block–poly (ethylene oxide) (PB‐b‐PS‐b‐PEO) and polyethylene–block–polystyrene–block–poly (ethylene oxide) (PE‐b‐PS‐b‐PEO) triblock terpolymers is analyzed under a thermal protocol. This allows the investigation of the morphology during the occurrence of thermal transitions, such as crystallization and melting, which is a neat way of studying the competition between microphase separation and crystallization for the morphology formation. Only one of the studied systems presented a morphological transition upon melting of the PEO and the PE blocks, attributed to the crystallization of the PE block in finite interconnected domains. All the other systems presented no morphological transitions during the thermal scan. The results prove that the crystallization only disrupt the microphases generated in the molten state under very specific circumstances for these block copolymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3197–3206, 2007
Influence of the Gas Humidity on the Uniformity of RF‐Powered Atmospheric‐Pressure Low‐Temperature DBD Plasmas
Authors: Koo Il Gyo , Cho Jin Hoon , Lee Woong Moo
Published: October 2007

The effect of the water level in a He working gas on the uniformity of the atmospheric pressure plasmas was investigated using emission spectroscopy. The 13.56 MHz rf‐powered dielectric barrier discharges were generated using He gas, in which water vapor of various concentrations was added. Electron density of the discharge medium determined using the emission spectra clearly demonstrated that the humidity level affects the electron density and the uniformity of the plasma.

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Influence of the Chemical Composition on the Phase Constitution and the Elastic Properties of RF‐Sputtered Hydroxyapatite Coatings
Authors: Snyders Rony , Bousser Etienne , Music Denis , Jensen Jens , Hocquet Stéphane , Schneider Jochen M.
Published: October 2007

We have studied the influence of chemical composition on the constitution and elastic properties of dense radio‐frequency (RF)‐sputtered hydroxyapatite (HA) coatings. The chemical composition was modified by varying the RF sputtering power density (PD). As the PD was increased by 240%, the Ca/P ratio measured by X‐ray photoelectron spectroscopy increased from ≈1.51 to ≈1.82. X‐ray diffraction indicates phase pure hexagonal HA except for the sample prepared at the highest PD where CaO and Ca3(PO4)2 also form. Deviations from the stoichiometric Ca/P ratio result in reduction of the elastic modulus. For Ca/P = 1.51 ± 0.02, the elastic modulus decreases by ≈15%. This may be due to incorporation of Ca vacancies in the lattice, while for Ca/P = 1.82 ± 0.02, the average elastic modulus decreases by ≈10% due to formation of additional phases.

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Determinants of airleak flow during humming V high‐frequency oscillatory ventilation in an open‐compartment ex‐vivo model of airleak
Authors: Liu Tao‐Yuan , Lien Shao‐Hung , Hua Yi‐Ming , Soong Wen‐Jue , Lu Pai , Yuh Yeong‐Seng
Published: October 2007

High‐frequency oscillatory ventilation (HFOV) using small tidal volumes and maintaining sufficient end‐expiratory lung volume may be beneficial in the treatment of airleak. However, few published guidelines exist to advise clinicians on appropriate ventilator settings in this clinical scenario. The present experiment aimed to determine the effect of frequency, stroke volume (SV) and mean airway pressure (MAP) on airleak from an isolated lung model ventilated with a Humming V HFOV. We performed a crossover non‐randomized experiment using the repeated measurement method to test the hypothesis that MAP is the major determinate for airleak. The lungs of 13 healthy juvenile New Zealand white rabbits were isolated and ventilated with high peak pressure to create airleak. The dataset obtained was analyzed using the generalized estimating equation method. We found that airleak flow did not change as frequency was raised from 13 to 17 Hz (P = 0.463) with MAP and SV kept constant. SV was positively correlated to the amount of change in airleak (P < 0.01, coefficients ± SEM = 1.2 ± 0.1 ml/min/ml). Leakage flow increased significantly from 275 ± 168 ml/min to 1,721 ± 552 ml/min as MAP was increased from 5 cm H2O to 30 cm H2O (P < 0.001, coefficients ± SEM = 56.1 ± 3.0 ml/min/cm H2O) while inspiratory flow increased less and amplitude pressure remained about the same. We concluded that MAP (lung volume) was the main independent factor for airleak, whilst SV (tidal volume) exerted a lesser effect. Within the operational range of the Humming V, frequency did not affect airleak. Pediatr Pulmonol. 2007; 42:1104–1109. © 2007 Wiley‐Liss, Inc.
Is a longer time interval between recombinant human deoxyribonuclease (dornase alfa) and chest physiotherapy better?: A multi‐center, randomized crossover trial
Authors: Wilson Christine J. , Robbins Lisel J. , Murphy Jennifer M. , Chang Anne B.
Published: October 2007

Background

Although the benefits of recombinant human deoxyribonuclease (dornase alfa) in patients with cystic fibrosis (CF) are established, its optimal timing in relation to physiotherapy is unknown. As its enzymatic effect lasts for 6–11 hr, dornase alfa may be more efficacious if the time interval between inhalation and chest physiotherapy is increased. The aim of this study was to investigate if a longer time interval between dornase alfa nebulization and chest physiotherapy improves clinical outcomes of subjects with CF.

Methods

A single‐blind randomized cross‐over trial was conducted on subjects with CF from outpatients of four hospitals. Subjects were in stable health and studied over 6 weeks (utilizing 14‐day blocks of morning or evening dornase alfa administration with 14 days washout). Usual regimens for physiotherapy and exercise were unaltered. Thus changing the times altered the dwell time of dornase alfa prior to physiotherapy. Long interval was defined as dwell time of >6 hr and short as ≤6 hr. Outcomes were measured at pre and post each regimen.

Results

Twenty subjects aged 7–40 years completed the study. At end of long interval regimen, (median interval = 11.1 hr), FEF25–75% and CF‐specific quality of life significantly improved compared to baseline values and to short interval regimen (median interval = 0.25 hr) outcomes. FVC, FEV1, sputum weights, and adherence were similar in both regimens.

Conclusions

A longer time interval between dornase alfa and physiotherapy is more efficacious than short interval. Administration timing of dornase alfa based on patient choice to incorporate longer interval time is likely to be the best regimen for patients previously established on dornase alfa nebulization. Pediatr Pulmonol. 2007; 42:1110–1116. © 2007 Wiley‐Liss, Inc.
Analysis of management actions, human behavior, and process reliability in chemical plants. I. impact of management actions
Authors: Meel Anjana , Seider Warren D. , Oktem Ulku
Published: October 2007

While management and engineering actions have a significant impact on process reliability, these factors have received too little attention in calculating plant risks. In this work, the focus is on understanding and modeling the influence of human behavior patterns on plant safety in two settings. The first, introduced in Part I, involves a framework to estimate the impacts of management and engineering decisions, process operator performance, and processing equipment operations on the failure state of chemical plants. As examples, the impacts of poor training, maintenance problems, operator inabilities, control system failures, and excessive feed quantities, on failure states are studied. The management and engineering team and the operators are found to have significant impacts on process reliability. While the theoretical framework introduced herein is illustrated using hypothetical plant data, it should provide a basis for more quantitative safety analyses. Attempts to obtain operating data in industrial plants for validation of the framework were unsuccessful because of confidentiality and liability issues associated with industrial data. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007
Characterization and fitness of carbendazim‐resistant strains of Fusarium graminearum (wheat scab)
Authors: Chen Changjun , Wang Jianxin , Luo Qingquan , Yuan Shankui , Zhou Mingguo
Published: October 2007

BACKGROUND: Carbendazim (MBC) has failed to control wheat scab, caused by Fusarium graminearum Schwabe, on the eastern coast of China in recent years after about 30 years of application.

RESULTS: MBC resistance was found to be common in pathogen populations on the eastern coast and along areas of the Yangze River. EC50 and minimum inhibitive concentration (MIC) values of MBC inhibiting mycelium growth of wild‐type isolates were less than 0.9 and 1.4 µg mL−1 respectively, while EC50 values of resistant collections averaged 7.02 ± 11.86 µg mL−1. The slope of the MBC dosage–response curve (DRC) for resistant isolates of F. graminearum was flat: 1 < b < 2.8 for resistant isolates and 3.5 < b < 11 for sensitive isolates). Both field resistant and sensitive MBC strains shared similar temperature sensitivity, fitness and virulence on ears. Field resistant strains and UV‐induced mutants showed positive cross‐resistance to other benzimidazole derivatives and were mainly at intermediate MBC resistance level. Highly resistant field MBC strains rarely appeared, but only some of the highly resistant MBC UV mutants were insensitive to N‐phenylaminecarbamates. No mutation in beta‐tubulin was found in F. graminearum, in contrast to mutation in this tubulin which has led to MBC resistance in other plant pathogens.

CONCLUSION: MBCR isolates have high fitness and competition in field, conferred by a novel molecular mechanism. Copyright © 2007 Society of Chemical Industry
25 years of Bayesian methods in the pharmaceutical industry: a personal, statistical bummel
Authors: Grieve Andrew P.
Published: October 2007

Twenty‐five years ago the use of Bayesian methods in Pharmaceutical R&D was non‐existent. Today that is no longer true. In this paper I describe my own personal journey along the road of discovery of Bayesian methods to routine use in the pharmaceutical industry. Copyright © 2007 John Wiley & Sons, Ltd.
Click Chemistry and ATRP: A Beneficial Union for the Preparation of Functional Materials
Authors: Golas Patricia L. , Matyjaszewski Krzysztof
Published: October 2007

Since the concept of highly efficient and selective “click” reactions was put forth by Sharpless and coworkers, this branch of chemical transformations has been subject to an astounding degree of applications. Although click chemistry encompasses a wide variety of reactions, the CuI‐catalyzed azide–alkyne cycloaddition has received the most attention. It has been increasingly employed in polymer functionalization and materials synthesis, especially in conjunction with controlled radical polymerization methods, such as Atom Transfer Radical Polymerization (ATRP). The CuI‐catalyzed azide–alkyne cycloaddition is utilized particularly well with ATRP, due to the ease of incorporating clickable functionality into polymers prepared by ATRP and the use of the same catalyst in each process. This minireview summarizes and analyzes recent developments in the field of CuI‐click chemistry as applied to ATRP, and how the combination of these two powerful techniques has greatly expanded the range of available materials and has contributed to fundamental understanding of this process.
Click Chemistry as a High‐Throughput Amenable Platform in Catalomics
Authors: Kalesh Karunakaran Anandamma , Yang Peng‐Yu , Srinivasan Rajavel , Yao Shao Qin
Published: October 2007

Click chemistry is emerging as a powerful tool to elucidate the complex catalytic functions that enzymes perform in the biological system. Recent advances in proteomics heavily rely on the robust, modular and high‐throughput platform offered by click chemistry. This minireview focuses on the central role click chemistry has played on the most recent advances in the chemical proteomic research involving the discovery of enzyme inhibitors and enzyme profiling using Activity‐Based Probes (ABPs). The strength and benefit of click chemistry and its novel variants, such as the so‐called in situ screening using click chemistry have been even more evident recently when this novel chemistry is coupled with high‐throughput assay technologies such as microarrays and characterization techniques such as Liquid Chromatography‐Mass Spectrometry in Selected Ion Mode (LCMS‐SIM) and multidimensional LC‐MS. The invaluable contribution of click chemistry in the emerging field of “Catalomics” is thus firmly established.
Optimization of Click Chemistry Using Azide and Alkyne Scavenger Resins
Authors: Leeb Laurin , Gmeiner Peter , Löber Stefan
Published: October 2007

The copper catalyzed [3+2]‐cycloaddition of azides and alkynes has attracted enormous attention due to its striking suitability for the construction of bioconjugates, polymers, and bioactive small molecules. We herein present new, readily approachable polymer‐supported scavenger resins allowing an efficient and high yielding parallel synthesis of 1,4‐substituted 1,2,3‐triazoles. Azidomethyl‐substituted polystyrene 1 and the alkynoylamino functionalized resin 3 proved to quantitatively remove unreacted alkynes and azides, respectively. Model libraries of triazole derivatives could be obtained in high yield and excellent purity suggesting the application of this practical methodology for parallel solution phase chemistry.
In Situ Functionalization of Thermoresponsive Polymeric Micelles using the “Click” Cycloaddition of Azides and Alkynes
Authors: Lutz Jean‐François , Pfeifer Sebastian , Zarafshani Zoya
Published: October 2007

Well‐defined surfactants, composed of a hydrophobic cholesterol moiety and a hydrophilic polymer segment, were synthesized via the atom transfer radical copolymerization of various oligo(ethylene glycol) (meth)acrylates initiated by Cholesteryl‐2‐Bromoisobutyrate (CBI). After polymerization, the bromine ω‐end‐groups of the surfactants were transformed into an azide function by nucleophilic substitution. Depending on their hydrophilic‐hydrophobic balance, these novel surfactants lead to different types of structures in pure deionized water. For instance, surfactants with a hydrophilic block based on Oligo(Ethylene Glycol) Methyl Ether Acrylate (OEGA) repeat units were found to be molecularly soluble in pure water, even for very short hydrophilic segments. On the other hand, surfactants based on copolymers of OEGA with the more hydrophobic monomer 2‐(2‐Ethoxyethoxy)Ethyl Acrylate (EEO2A) formed defined micellar aggregates (Dh∼100 nm) in aqueous solution. These aggregates were found to be thermoresponsive and exhibited a lower critical solution temperature in water at approximately 45 °C. Moreover, the outer‐corona of these micellar assemblies could be successfully functionalized in situ using the copper‐catalyzed “click” cycloaddition of azides and alkynes. For instance, the azide functions of the surfactants could be efficiently “clicked” to propargyl alcohol at room temperature and in dilute aqueous solutions. FTIR and 1H NMR measurements indicated that the yield of click cycloaddition was in most cases above 95%.
Rotaxanes and Catenanes by Click Chemistry
Authors: Miljanić Ognjen Š. , Dichtel William R. , Aprahamian Ivan , Rohde Rosemary D. , Agnew Heather D. , Heath James R. , Fraser Stoddart J.
Published: October 2007

Copper(I)‐catalyzed Huisgen 1,3‐dipolar cycloaddition between terminal alkynes and azides – also known as the copper (Cu)‐catalyzed Azide‐Alkyne Cycloaddition (CuAAC) – has been used in the syntheses of molecular compounds with diverse structures and functions, owing to its functional group tolerance, facile execution, and mild reaction conditions under which it can be promoted. Recently, rotaxanes of four different structural types, as well as donor/acceptor catenanes, have been prepared using CuAAC, attesting to its tolerance to supramolecular interactions as well. In one instance of a rotaxane synthesis, the catalytic role of copper has been combined successfully with its previously documented ability to preorganize rotaxane precursors, i.e., form pseudorotaxanes. The crystal structure of a donor/acceptor catenane formed using the CuAAC reaction indicates that any secondary [π⋅⋅⋅π] interactions between the 1,2,3‐triazole ring and the bipyridinium π‐acceptor are certainly not destabilizing. Finally, the preparation of robust rotaxane and catenane molecular monolayers onto metal and semiconductor surfaces is premeditated based upon recent advances in the use of the Huisgen reaction for surface functionalization.
Application of the 1,3‐Dipolar Cycloaddition Reaction in Chemical Biology: Approaches Toward Multivalent Carbohydrates and Peptides and Peptide‐Based Polymers
Authors: Pieters Roland J. , Rijkers Dirk T. S. , Liskamp Rob M. J.
Published: October 2007

In this mini review we highlight our recent results and the related literature regarding the application of the Cu(I)‐catalyzed 1,3‐dipolar cycloaddition “click” reaction. The synthetic applications of the click reaction focus on multivalent carbohydrates and peptides and peptide‐based polymers. Furthermore, a related reaction is described involving the coupling of thio acids and sulfonyl azides leading to the chemoselective formation of amides.
Model Studies Toward the Synthesis of Thymidine Oligonucleotides with Triazole Internucleosidic Linkages Via Iterative Cu(I)‐Promoted Azide–Alkyne Ligation Chemistry
Authors: Nuzzi Andrea , Massi Alessandro , Dondoni Alessandro
Published: October 2007

Given the importance of non‐natural oligodeoxyribonucleotide antisense agents acting as inhibitors of target deleterious genes responsible for various diseases, a new approach has been explored to oligothymidines in which triazole internucleosidic linkages replace the native phosphodiester groups. The designed approach is based on the repetition of the copper(I)‐catalyzed azide–alkyne cycloaddition as a key ligation process of suitably functionalized thymidine building blocks. The viability of the method has been demonstrated by the preparation of a triazole‐linked trinucleoside, i.e., a non‐natural “triazole codon”.
From (bio)Molecules to Biohybrid Materials with the Click Chemistry Approach
Authors: Dirks A. (Ton) J. , Cornelissen Jeroen J. L. M. , van Delft Floris L. , van Hest Jan C. M. , Nolte Roeland J. M. , Rowan Alan E. , Rutjes Floris P. J. T.
Published: October 2007

In order to construct biologically active materials for applications in nanotechnology and medicine, materials scientists have extensively explored the use of nature‐derived building blocks, in particular amino acids, carbohydrates, and lipids. Typically, these building blocks are assembled into larger arrays, or attached to synthetic scaffolds or other biomolecules, in such a way that novel biohybrid materials can be obtained with new or improved properties. To ensure that the original activity of the building blocks herein is preserved, the construction of biohybrid materials needs to proceed in a well‐defined manner employing selective coupling techniques with a high functional group tolerance. Consequently, the concept of “click chemistry” has rapidly established a prominent role in the synthesis of these types of biologically active materials. In particular, the Cu‐catalyzed Azide‐Alkyne [3+2] Cycloaddition (CuAAC) has proven to be extremely valuable to many researchers in the field of biohybrid materials science, including our own groups. This mini‐review will focus on the application of the CuAAC in the construction of biohybrid materials and will discuss our recent efforts as well as related work from other groups.
Microwave‐Assisted Click Chemistry for the Preparation of 3‐ and 4‐Triazolyl‐2(1H)‐quinolones as Potential Fluorescent Probes
Authors: Glasnov Toma N. , Kappe C. Oliver
Published: October 2007

Synthetic pathways toward the preparation of selected 3‐ and 4‐triazolyl‐2(1H)‐quinolones with expected fluorescent properties were investigated. Crucial steps for the synthesis were the Cu(I)‐catalyzed 1,3‐dipolar cycloaddition of an organic azide to a terminal acetylene (click chemistry) as well as the photochemical rearrangement of quinoline N‐oxides into quinoline‐2(1H)‐ones. The click procedure was facilitated by controlled microwave irradiation.
Synthesis of Furo[2,3‐b]pyrazine Nucleoside Analogues with 1,2,3‐Triazole Linkage
Authors: Ermolat'ev Denis S. , Mehta Vaibhav Pravinchandra , Van der Eycken Erik V.
Published: October 2007

Sonogashira coupling reaction with the readily available 1‐(4‐methoxybenzyl)‐3,5‐dichloropyrazin‐2(1H)‐ones was followed by mild silver‐catalyzed cyclization to provide the corresponding 2‐chlorofuro[2,3‐b]pyrazines in excellent yields. A second Sonogashira cross‐coupling reaction resulted in the formation of 2‐ethynylfuro[2,3‐b]pyrazines, which were coupled with D‐ribose and 2‐deoxy‐D‐ribose using a microwave‐assisted Cu(I)‐catalyzed Huisgen [2+3] dipolar cycloaddition reaction, to generate a small library of new nucleoside analogues.
The Bayesian aerosol release detector: An algorithm for detecting and characterizing outbreaks caused by an atmospheric release ofBacillus anthracis
Authors: Hogan William R. , Cooper Gregory F. , Wallstrom Garrick L. , Wagner Michael M. , Depinay Jean‐Marc
Published: October 2007

Early detection and characterization of outdoor aerosol releases ofBacillus anthracisis an important problem. As health departments and other government agencies address this problem with newer methods of surveillance such as environmental surveillance through the BioWatch program and enhanced medical surveillance, they increasingly have newer types of surveillance data available. However, existing methods for the statistical analysis of surveillance data do not account for recent meteorological conditions, as human analysts did in the case of the Sverdlovsk anthrax outbreak of 1979 to determine whether the locations of victims were consistent with meteorological conditions in the week preceding their onset of illness.

This paper describes the Bayesian aerosol release detector (BARD), an algorithm that analyzes both medical surveillance data and meteorological data for early detection and characterization of outdoor releases ofB. anthracis. It estimates a posterior distribution over the location, quantity, and date and time conditioned on a release having occurred. We report a proof‐of‐concept evaluation of BARD, which demonstrates that the approach shows promise and warrants further development and evaluation. Copyright © 2007 John Wiley & Sons, Ltd.
A local sensitivity analysis approach to longitudinal non‐Gaussian data with non‐ignorable dropout
Authors: Xie Hui
Published: October 2007

Longitudinal non‐Gaussian data subject to potentially non‐ignorable dropout is a challenging problem. Frequently an analysis has to rely on some strong but unverifiable assumptions, among whichignorabilityis a key one. Sensitivity analysis has been advocated to assess the likely effect of alternative assumptions about dropout mechanism on such an analysis. Previously, Maet al.applied a generalindex of local sensitivity to non‐ignorability(ISNI) to measure the sensitivity of missing at random (MAR) estimates to small departures from ignorability for multivariate normal outcomes. In this paper, we extend the ISNI methodology to handle longitudinal non‐Gaussian data subject to non‐ignorable dropout. Specifically, we propose to quantify the sensitivity of inferences in the neighborhood of an MAR generalized linear mixed model for longitudinal data. Through a simulation study, we evaluate the performance of the proposed methodology. We then illustrate the methodology in one real example: smoking‐cessation data. Copyright © 2007 John Wiley & Sons, Ltd.
Multinational HRM in privatized Jordanian enterprises: An exploration of the influence of political contingencies
Authors: Al‐Husan Faten Baddar , James Philip
Published: October 2007

Within the international human resource management literature, it is recognized that a range of “host‐country effects” can influence how multinational corporations approach the management of human resources within overseas subsidiaries. This article seeks to further knowledge of these effects by using the findings obtained from two case studies conducted in companies that had come under the control of French multinationals through the Jordanian government's privatization program to explore how subsequent processes of human resource reform were shaped by governmental policies and wider political considerations and the dynamics underlying these shaping processes. In particular, it explores the tensions that arose between government policies and corporate business objectives, the negotiating strategies that the companies adopted in order to resolve them, and the factors that influenced the usage and outcome of these strategies. © 2007 Wiley Periodicals, Inc.
Entry barriers of small and medium‐sized software firms in the Japanese market
Authors: Ojala Arto , Tyrväinen Pasi
Published: October 2007

The Japanese software market size was U.S. $131,773 million in 2004. Due to limited domestic software production, Japan is highly dependent on imported software products. Despite the market potential for foreign software firms in Japan, almost no research exists on what kind of challenges foreign software firms encounter when they are entering the market. To fill this gap, this article investigates the entry barriers of small and medium‐sized software firms in the Japanese market by using a multicase study. The findings suggest that most of the barriers are firm‐specific and mainly related to firms' resources and capabilities to operate in the market. The entry barriers encountered also seem to differ somewhat from earlier investigations, which have mainly targeted large manufacturing firms. The new observations included common barriers related to the intensive information flow of customization and localization needs and market requirements of software products. The findings are useful for both practice and further research. © 2007 Wiley Periodicals, Inc.
Interval timed coloured Petri net: efficient construction of its state class space preserving linear properties
Authors: Boucheneb Hanifa
Published: October 2007

We consider here the interval timed coloured Petri net model (ITCPN). This model associates with each created token a time interval specifying when the token will become available and forces enabled transitions to occur as soon as possible. This model can simulate other timed Petri nets and allows to describe large and complex real-time systems. We propose a much more efficient contraction for its generally infinite state space than those developed in the literature. Our contraction approach captures all linear properties of the model and produces finite graphs for all bounded models.