bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractDeveloping 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

AbstractFor 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

AbstractA 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

AbstractMulti‐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

AbstractIsothermal 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

AbstractThe 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

AbstractThe 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

AbstractIn 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

AbstractThe 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

AbstractThe 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.magnified image
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

AbstractWe 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.magnified image
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

AbstractHigh‐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

AbstractBackgroundAlthough 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.MethodsA 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.ResultsTwenty 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.ConclusionsA 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

AbstractWhile 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

AbstractBACKGROUND: 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

AbstractTwenty‐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

AbstractSince 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

AbstractClick 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.