bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and properties of organic soluble semicrystalline poly(aryl ether ketone)s copolymers containing phthalazinone moieties
Authors: Sun Qingmin , Wang Jinyan , He Lishan , Song Yuan , Jian Xigao
Published: February 2007

A series of poly(aryl ether ketone)s (PAEK) copolymers containing phthalazinone moieties were synthesized by modest polycondensation reaction from 4‐(4‐hydroxyl‐phenyl)‐(2H)‐phthalazin‐1‐one (DHPZ), hydroquinone (HQ), and 1,4‐bis(4‐fluorobenzoyl)benzene (BFBB). The Tg values of these copolymers ranged from 168 to 235°C, and the crystalline melting temperatures varied from 285 to 352°C. By introducing phthalazinone moieties into the main chain, the solubility of these copolymers was improved in some common polar organic solvents, such as chloroform (CHCl3), N‐methyl‐2‐pyrrolidinone (NMP), nitrobenzene (NB) and so on. The values of 5% weight loss temperatures were all higher than 510°C in nitrogen. The crystal structures of these copolymers were determined by wide‐angle X‐ray diffraction (WAXD), which revealed that they were semicrystalline in nature, and the crystal structure of these copolymers was orthorhombic, equal to poly(ether ether ketone ketone)s. As phthalazinone content in the backbone varied from 0 to 40 mol % (mole percent), the cell parameters of these copolymers including the a, b, and c axes lengths ranged from 7.76 to 7.99 Å, 6.00 to 6.14 Å, and 10.10 to 10.19 Å, respectively. The degree of crystallinity (via differential scanning calorimetry) decreased from 37.70% to 16.14% simultaneously. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1744–1753, 2007
Compression‐molded, lubricant‐treated UHMWPE composites
Authors: Puukilainen Esa , Saarenpää Hanna , Pakkanen Tapani A.
Published: February 2007

Lubricant‐treated ultra high molecular weight polyethylene (UHMWPE) composites were prepared by compression molding. Composites were made from mixtures containing up to 5.0 wt % of lubricant. Two solid lubricants, molybdenum disulfide (MoS2), and carbon black (CB), and one liquid lubricant, perfluoropolyether (PFPE), were used in the study. UHMWPE and the lubricants formed 3D networks, where the lubricant was evenly spread over the UHMWPE particles. The amounts of MoS2 and CB were determined by thermogravimetric analyses, and the amounts of PFPE by ATR‐IR spectroscopy. All the lubricant treated composites showed better friction properties than pure UHMWPE. The addition of PFPE to UHMWPE improved the hydrophobicity of the surface, whereas the addition of solid lubricant had little effect. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1762–1768, 2007
Removal of environmentally impacting metal ions using functional resin poly(4‐styrene sulfonate‐co‐4‐vinylpyridine): Synthesis and metal ion retention properties
Authors: Rivas Bernabé L. , Muñoz Carla
Published: February 2007

A water‐insoluble polymer, poly(sodium 4‐styrene sulfonate‐co‐4‐vinylpyridine), was synthesized by radical polymerization at different amounts (2, 4, 6, and 8 mol %) of crosslinking reagent (CR). The polymerization yield ranged from 83.5% to 100.0%. The resin is characterized by FT IR spectroscopy, thermal analysis, and scanning electron microscopy. The water absorption capacity, WAC (110 g/g dry resin), was obtained for the resin with a 2 mol % of CR. The metal ion affinity is studied by Batch equilibrium procedure under different experimental conditions for the cations: Hg(II), Cd(II), Zn(II), Pb(II), Cr(III), and Al(III). The metal ion affinity increased as the pH increased. At pH 5, the resin presented an affinity above 90% for all metal ions. Hg(II) presented the highest retention value at pH 2. The maximum metal ion retention capacity is determined at optimum pH for Hg(II), Cd(II), Pb(II), and Zn(II). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1769–1774, 2007
Search for simulants of sulfur mustard through sorption studies in elastomers
Authors: Parmar Toral , Dubey Vinita , Agarwal D. D.
Published: February 2007

With an aim to probe some of the safe and commercially available nonsulfur chemicals as simulants of sulfur mustard for testing of protective materials, the sorption of bis(2‐chloroethyl) ether (2‐CEE), 1,6‐dichlorohexane, bis(4‐chlorobutyl) ether, n‐octane (OCT), dimethyl methylphosphonate, and ethylene glycol through butyl rubber (IIR) and polyisoprene (PI) rubber was studied at 30 ± 2°C using gravimetric method. Among these compounds, sorption of OCT was maximum while bis(4‐chlorobutyl) ether was sorbed least. The sorption of dimethyl methylphosphonate was intermediate between 2‐CEE and 1,6‐dichlorohexane. With the exception of OCT/IIR, OCT/PI, and 2‐CEE/PI, all other simulant/elastomer systems showed non‐Fickian behavior, implying the potential of OCT as a model compound. The diffusivity of OCT was investigated in IIR and PI; the diffusion coefficient values for OCT/IIR and OCT/PI systems differed by one order of magnitude, being 6.95 × 10−15 m2/s and 3.74 × 10−14 m2/s, respectively, indicating the relative impermeability of IIR. The magnitude and dynamics of sorption in OCT/IIR as a function of its concentration and the amount of filler were further studied using the automated gravimetric analyzer. Incorporation of carbon black in IIR further reduced the extent of sorption, thereby implying an improvement in barrier performance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1801–1806, 2007
Poly(methylmethacrylate)‐poly(vinyl pyrrolidone) microspheres as drug delivery systems: Indomethacin/cefadroxil loading and in vitro release study
Authors: Sairam M. , Ramesh Babu V. , Krishna Rao K. S. V. , Aminabhavi T. M.
Published: February 2007

Poly(methylmethacrylate)‐poly(vinyl pyrrolidone) (PMMA‐PVP) microspheres loaded with cefadroxil (water‐soluble) and indomethacin (water‐insoluble) drugs have been prepared by the dispersion polymerization technique using PVP as a steric stabilizer. Microspheres have been characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X‐ray diffraction (X‐RD) studies. DSC studies indicated coating of PVP onto PMMA microspheres. SEM suggested the formation of microspheres in the size of around 5 μm. X‐RD confirmed that drug has been highly dispersed in polymer particles. Higher encapsulation efficiency of up to 84% was achieved for hydrophobic drug, indomethacin than for hydrophilic cefadroxil. In vitro release studies performed in pH 7.4 phosphate buffer saline indicated that release of indomethacin was controlled up to 12 h, whereas cefadroxil was released in a controlled manner up to 10 h. During in vitro release, properties of both the drugs remained unaltered. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1860–1865, 2007
Preparation of hydroxyapatite/Ca‐alginate composite microspheres via inverse suspension crosslinked method
Authors: Liu Chao , Ji Xiujie , Zhao Kongyin , Cheng Guoxiang
Published: February 2007

Composite microspheres were prepared with hydroxyapatite (HA) and Na‐alginate (ALG) via inverse suspension crosslinked method (ISCM). Chloroform/hexane (1 : 2 (volume)) was used as continuous phase, ethyl cellulose (EC) as disperser, mixture of HA powder and ALG solution as dispersed phase, and calcium chloride as crosslinking agent. Morphology of the composite microspheres and HA distribution state were observed by optical microscope. According to the compositions studied, the sample with 0.2 g of EC gives the best continuous phase. The sample with 25 mL/min of adding speed and 120 r/min of stirring speed gives the best adding and stirring conditions. Two kind of the composite microspheres of 50/50 and 70/30 HA/ALG were prepared via ISCM. They are with specific gravity of 1.06 and 1.15, and water content of 88 and 81%, respectively. The size of the dried microspheres is mainly in the range of 125–425 μm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2034–2038, 2007
Electrochemical synthesis of polyaniline and its comparison with chemically synthesized polyaniline
Authors: Bhadra Sambhu , Singha Nikhil K. , Khastgir Dipak
Published: February 2007

The synthesis of polyaniline (PAni) powder was carried out from 0.15M of aniline and 1M of HCl in distilled water at room temperature in a single compartment electrochemical cell. The PAni was again synthesized chemically keeping the composition and temperature same as electrochemical process but adding equimolar amount of ammonium peroxydisulfate as an oxidizing agent. Then the PAni obtained from these two methods were characterized by the conductivity, solubility, X‐ray, FTIR, TGA, UV, and SEM, and compared. Result shows that the electrochemically synthesized PAni (ECS‐PAni) has somewhat lower conductivity, higher solubility, more benzenoid rings than quinoid rings, lower crystallinity, higher band energy, and higher particle size than that of chemically synthesized PAni (CS‐PAni). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1900–1904, 2007
Preparation and characterization of surfactant‐free stimuli‐sensitive microgel dispersions
Authors: Griffin James M. , Robb Ian , Bismarck Alexander
Published: February 2007

A surfactant‐free method to produce responsive polymer microgels is introduced. As an example, poly(methacrylic acid) hydrogels with varying crosslinking density have been synthesized in bulk and then chopped using a high shear mechanical cutter to form microgel particles dispersed in water. The mechanical cutting technique enables the concentration and particle size distribution of the microgel suspensions to be easily controlled, therefore making the rheology of the suspensions tuneable. The particle size distribution of the dispersions, characterized using light scattering, was dependent on the speed and duration of mechanical cutting. The particle size distribution also depended on the degree of crosslinking of the hydrogel. The higher the crosslinking density, the lower the average mean diameter of the resulting microgel particles. The lower the crosslinking density of the hydrogel, the larger the difference between the maximum and minimum particle size. The time to complete swelling of the particles upon change in pH was measured to be up to 45 s, depending on the particle size. The rheology of the resulting suspensions as a function of pH was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 104: 1912–1919, 2007
Electropolymerization of PoPD from aqueous solutions of sodium dodecyl benzene sulfonate at conducting glass electrode
Authors: Zhang Xiu‐Hua , Wang Shi‐Min , Wu Jie , Liu Xian‐Jie
Published: February 2007

Electropolymerization of poly‐(o‐phenylenediamine) (PoPD) film was performed in a micellar aqueous solution containing sodium dodecyl benzene sulfate (SDBS) by cyclic voltammetry at conducting glass electrode. The experimental results showed that the anionic micelle, i.e., SDBS, can greatly catalyze the electropolymerization reaction of oPD and reduce its oxidation potential from 0.97 to 0.74 V (vs. saturated calomel electrode). In the anionic micellar media, the local concentration of o‐phenylenediamine (oPD) on the surface of electrode may be increased, and the oPD cation radicals are more stabilized in the hydrophobic microcircumstance of micelle, which is available to avoid hydrolysis degradation of PoPD and enhance the stability of the PoPD film. The spectroscopy and morphology of the films were characterized by FTIR spectroscopy and atomic force microscopy, respectively. The results suggested the possible presence of columnar structures when the electropolymerization is performed in the micellar medium. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1928–1932, 2007
Removal of chromium from waste water using polyaniline
Authors: Eisazadeh Hossein
Published: February 2007

One of the suitable methods for removing heavy metals from waste water is using surface adsorption process. In this article, the preparation of polyaniline and its composites as adsorbents are discussed and the capability of separating chromium from industrial waste water is studied. The results were compared with anthracite and cation exchangers such as purolite‐302 and amberjet. The observations indicated that the purolite and amberjet have the most chromium removal percentage. Also the role of polyaniline and its composite as adsorbents were studied. The results show that the percentage of chromium removal has increased in polyaniline/poly(vinyl alcohol) composite. Furthermore, the adsorption percentage is related to the surface morphology, type of adsorbents, and their weight ratios. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1964–1967, 2007
The effect of different sterilization procedures on chitosan dried powder
Authors: Yang Yu‐Min , Zhao Ya‐Hong , Liu Xiao‐Hua , Ding Fei , Gu Xiao‐Song
Published: February 2007

The aim of this study was to investigate the effects induced by three different sterilization methods [steam, γ‐radiation, and ethylene oxide (EO)] with different dose or time period of sterilization by means of Fourier transform infrared spectroscopy, X‐ray diffraction, and assessments of molecular weight and degree of deacetylation. The experiment results clearly showed that the steam sterilization greatly darkened the color of chitosan powder; γ‐irradiation strongly depolymerized the chitosan especially at irradiation dose above 10 kGy; and exposure to EO led to minor change in crystallinity and network structure of chitosan powder. Therefore, these three methods have their respective advantages and disadvantages, suggesting that the selection of the sterilization method of chitosan should depend upon the specific requirement of the final application. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1968–1972, 2007
Surface modification of radiation‐grafted polymer films and membranes by crosslinking
Authors: Schnyder Bernhard , Rager Timo
Published: February 2007

The surface composition of radiation‐grafted FEP‐g‐poly(styrene‐co‐divinylbenzene) films and its sulfonated analogues was investigated by X‐ray photoelectron spectroscopy. These investigations demonstrate that the surface composition is strongly influenced by the degree of crosslinking of the polystyrene phase. In the absence of a crosslinker, the surface concentration of the grafting component was high and could even exceed the calculated average concentration in the volume of the polymer. With increasing crosslinker concentration, the surface concentration of the grafting component decreased rapidly and became close to zero for crosslinker concentrations above 2% in the monomer mixture. The effect was most pronounced in the case of grafted films and weaker in the case of sulfonated membranes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1973–1978, 2007
Effect of the variation in the weight percentage of the loading and the reduction in the nanosizes of CaSO4 on the mechanical and thermal properties of styrene–butadiene rubber
Authors: Mishra S. , Shimpi N. G.
Published: February 2007

The incorporation of fillers into elastomers has profound effects on the mechanical, physical, and thermal properties of the nanocomposites that form. In this study, styrene–butadiene rubber as a matrix was reinforced separately with 10‐, 15‐, or 23‐nm CaSO4, which was synthesized by an in situ deposition technique. The mixing and compounding were performed on a two‐roll mill, and sheets were prepared in a compression‐molding machine. Properties such as the swelling index, specific gravity, tensile strength, elongation at break, modulus at 300% elongation, Young's modulus, hardness, and abrasion resistance were measured. The morphology of the rubber nanocomposites was also performed with scanning electron microscopy to study the dispersion of the nanofiller in the rubber matrix. The thermal decomposition of the rubber nanocomposites was studied with thermogravimetric analysis, and the results were compared with those of commercial CaSO4‐filled styrene–butadiene rubber. A reduction in the nanosizes of CaSO4 led to an enhancement of the mechanical, physical, and thermal properties of the rubber nanocomposites. Above a 10 wt % filler loading, the styrene–butadiene rubber showed a reduction in all properties. This effect was observed because of the agglomeration of the nanoparticles in the rubber matrix. The thermodynamic parameters were also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2018–2026, 2007
Morphology, structure, and conductivity of polypyrrole prepared in the presence of mixed surfactants in aqueous solutions
Authors: Xing Shuangxi , Zhao Guoku
Published: February 2007

Polypyrrole (PPy) was prepared from different mixed‐surfactant solutions with ammonium persulfate as an oxidant. Three types of combinations were selected, including cationic/anionic, cationic/nonionic, and anionic/nonionic mixed‐surfactant solutions. The surfactants used in the experiments included cetyltrimethylammonium bromide (cationic surfactant), sodium dodecyl sulfate (anionic surfactant), sodium dodecyl sulfonic acid salt (anionic surfactant), poly(vinyl pyrrolidone) (nonionic surfactant), and poly(ethylene glycol) (nonionic surfactant). The morphology, structure, and conductivity of the resulting PPy were investigated in detail with scanning electron microscopy, Fourier transform infrared spectra, and the typical four‐probe method, respectively. The results showed that the interaction between the different surfactants and the interaction between the surfactants and the polymer influenced the morphology, structure, and conductivity of the resulting polymer to different degrees. The cationic surfactant favored the formation of nanofibers, the addition of anionic surfactants produced agglomeration but enhanced the doping level and conductivity, and the presence of a nonionic surfactant weakened the interaction between the other surfactant and the polymer in the system. In comparison with the results for monosurfactant solutions, the polymerization of pyrrole in mixed‐surfactant solutions could modulate the morphologies of PPy, which ranged from nanofibers of different lengths to nanoparticles showing various states of aggregation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1987–1996, 2007
Synthesis of crosslinked superabsorbent carboxymethyl cellulose/acrylamide hydrogels through electron‐beam irradiation
Authors: Ibrahim Sayeda M. , El Salmawi Kariman M. , Zahran A. H.
Published: February 2007

A study on the possibility of the preparation of superabsorbent hydrogels based on crosslinked carboxymethyl cellulose polymer and acrylamide monomer through electron‐beam irradiation was carried out. The effects of the irradiation dose and polymer–monomer compositions on the crosslinking density were studied. The hydrophilic properties of the superabsorbent hydrogels were identified by the swelling percentage. The prepared hydrogels had higher swelling in distilled water than in salt solutions. Moreover, the hydrogels exhibited the highest swelling at pH 7. Also, increasing the temperature up to 50°C caused an increase in the swelling. The thermal properties of the hydrogels were characterized with thermogravimetric analysis. The use of the prepared superabsorbent hydrogels for the growth of rice was also investigated through the water‐retention property. The water retention in the soil was enhanced with the hydrogels. Superabsorbent hydrogels based on carboxymethyl cellulose polymer and acrylamide monomer could be considered as water‐managing materials for agriculture and horticulture in desert and drought‐prone areas. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2003–2008, 2007
The publishing dynamics of catastrophic events
Authors: W. Weessies Kathleen
Published: February 2007

This article studies the effect that two major disasters, the Three Mile Island nuclear disaster and the Chernobyl nuclear disaster, had on the publishing world. We expect consumer publishing to concentrate on major events as they unfold. The technical and scholarly publishing world, however, is believed to progress and develop in conjunction with the growth of science, as established in bibliometric laws. Articles about these disasters were tracked in four bibliographic databases representing scholarly, technical‐scholarly, technical, and consumer literature. Several analyses of the data revealed that each body of literature responds in its own way to disasters and anniversaries of events affect publishing, other than government‐sponsored research. More focused databases have a more highly correlated response to disasters than broad‐based databases. Comparison to two previously published studies of fast‐growing literatures reveals that while some measures are consistent, disasters experience participation from a larger number of researchers with publications spread across a broader base of journal titles.
Chemoselective C(sp3)H Bond Activation for the Preparation of Condensed N‐Heterocycles
Authors: Ren Hongjun , Li Zhuo , Knochel Paul
Published: February 2007

Condensed N‐heterocycles were prepared by using CH activation reactions catalyzed by Pd(OAc)2 (5 mol %) and (p‐tolyl)3P (10 mol %). The key step of these ring closures is chemoselective intramolecular CH activation of the methyl group at position 2 of the pyrrole ring. Functionalized 9H‐pyrrolo[1,2‐a]indoles and pyrrolo[1,2‐f]phenanthridine derivatives were prepared in good yields. The preparation of some complex N‐heterocycles by using successive reactions is also described.
Recent Progress in the Catalytic Synthesis of Imidazoles
Authors: Kamijo Shin , Yamamoto Yoshinori
Published: February 2007

Imidazole is one of the important heteroaromatic compounds that have found a broad range of uses in, for example, pharmaceutical and industrial applications. Several conventional methodologies for the synthesis of imidazole rings are known; however, they are limited in terms of substrate generality and are not always efficient. Recent studies toward the development of catalytic reactions have brought significant improvements to the preparation of imidazoles. This Focus Review highlights the very recent progress in the catalytic synthesis of imidazoles, particularly those involving the formation of five‐membered ring cores.
VCD spectroscopic and molecular dynamics analysis of the Trp‐cage miniprotein TC5b
Authors: Copps Jeffrey , Murphy Richard F. , Lovas Sándor
Published: February 2007

TC5b is a 20 residue polypeptide notable for its compact tertiary structure, a rarity for a short peptide. This structure is due to the “Trp‐cage“ motif, an association of aromatic, Pro, and Gly residues. The structure of TC5b has been fully characterized by NMR and electronic circular dichroism (ECD) studies, but has never been studied with vibrational circular dichroism (VCD) spectroscopy, which may reveal finer structure. In this study, we examine the VCD spectra of TC5b to characterize the spectroscopic signature of the peptide and its comprising structural elements. TC5b exhibited a negative‐positive‐negative triplet which is associated with α‐helical structure in deuterated solvents but also signs of a polyproline II (PPII) helix in the amide I' region. Detection of this element was complicated by the aforementioned triplet form, as well as by an upfrequency shift in PPII helical elements due to the use of the deuterated organic solvents DMSO‐d6 and TFE‐d1. Nevertheless, while ECD spectra showed only α‐helical structure for TC5b, VCD spectroscopy revealed a more complex structure which was in agreement with NMR results. VCD spectroscopy also showed a rapid conformational change of the peptide at temperatures above 35°C in D2O and in aqueous solvent with greater than 75% DMSO‐d6 content. Molecular dynamics (MD) simulations to investigate this latter effect of DMSO‐d6 on TC5b were conducted in DMSO and 50% (v/v) DMSO in H2O. In DMSO unfolding of the peptide was rapid while in 50% (v/v) DMSO in H2O the unfolding was more gradual. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 427–437, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
‘Everybody's entitled to their own opinion’: ideological dilemmas of liberal individualism and active citizenship
Authors: Condor Susan , Gibson Stephen
Published: February 2007

Conversational interview accounts were used to explore everyday understandings of political participation on the part of young white adults in England. Analysis focussed on dilemmatic tensions within respondents' accounts between values of active citizenship and norms of liberal individualism. Respondents could represent community membership as engendering rights to political participation, whilst also arguing that identification with local or national community militates against the formulation of genuine personal attitudes and rational political judgement. Respondents could represent political participation as a civic responsibility, whilst also casting political campaigning as an illegitimate attempt to impose personal opinions on to others. Formal citizenship education did not appear to promote norms of political engagement but rather lent substance to the argument that political decision‐making should be based on the rational application of technical knowledge rather than on public opinion or moral principle. In conclusion we question whether everyday understandings of responsible citizenship necessarily entail injunctions to political action. Copyright © 2007 John Wiley & Sons, Ltd.
UK students and sex work: current knowledge and research issues
Authors: Roberts Ron , Bergström Sandra , La Rooy David
Published: February 2007

Available evidence, largely arecdotal suggests that students are turning to quick ways of making money such as work in the sex industry in order to balance their finances, a trend seen in other countries with similar student support and tuition fee policies. Further research is urgently needed to understand the scale of student involvement in sex work and to clarify our understanding of the factors that influence the decision to engage in it. Unfortunately a number of methodological, practical and political problems stand in the way of such research. These are discussed together with preliminary findings from an exploratory study. Copyright © 2007 John Wiley & Sons, Ltd.
Control and Selectivity of Photosensitized Singlet Oxygen Production: Challenges in Complex Biological Systems
Authors: Cló Emiliano , Snyder John W. , Ogilby Peter R. , Gothelf Kurt V.
Published: February 2007

Singlet molecular oxygen is a reactive oxygen species that plays an important role in a number of biological processes, both as a signalling agent and as an intermediate involved in oxidative degradation reactions. Singlet oxygen is commonly generated by the so‐called photosensitization process wherein a light‐absorbing molecule, the sensitizer, transfers its energy of excitation to ground‐state oxygen to make singlet oxygen. This process forms the basis of photodynamic therapy, for example, where light, a sensitizer, and oxygen are used to initiate cell death and ultimately destroy undesired tissue. Although the photosensitized production of singlet oxygen has been studied and used in biologically pertinent systems for years, the photoinitiated behaviour is often indiscriminate and difficult to control. In this Concept, we discuss new ideas and results in which spatial and temporal control of photosensitized singlet oxygen production can be implemented through the incorporation of the sensitizer into a conjugate system that selectively responds to certain triggers or stimuli.
Isolation of Rhenium and ReOx Species within ZSM5 Channels and their Catalytic Function in the Activation of Alkanes and Alkanols
Authors: Lacheen Howard S. , Cordeiro Paul J. , Iglesia Enrique
Published: February 2007

Synthesis protocols, structures, and reactivity of Re–oxo species grafted onto HZSM5, and their subsequent conversion to Re‐clusters through contact with H2 or CH4 were studied by using Raman, infrared, and X‐ray absorption spectroscopies. Reactivity measurements by using alkane and alkanol reactants were also examined. Sublimation of Re2O7 at 723 K led to a stoichiometric exchange with each ReOx species replacing one proton. Raman features for Re2O7 disappeared during thermal treatment and Raman bands assigned to distorted‐tetrahedral Si‐OfReO3‐Al (Of: zeolite‐lattice oxygen atoms) species emerged; infrared bands for acidic OH groups in HZSM5 weakened concurrently. X‐ray absorption near‐edge and fine‐structure spectra detected the formation of distorted‐tetrahedral Re7+–oxo species during thermal treatment of Re2O7/HZSM5 mixtures in air, and their subsequent reduction to Re0 in H2 or CH4 to form encapsulated Re metal clusters similar in diameter (≈8 Å) to the channel intersections in ZSM5. Si‐OfReO3‐Al species in ReOxZSM5 catalyzed the oxidative conversion of C2H5OH to acetaldehyde, acetal, and ethyl acetate with very low selectivity to COx (<1 %). Unprecedented turnover rates were exhibited at temperatures much lower than previously found for ReOx–based catalysts, and without deactivation or sublimation processes ubiquitous in crystalline Re7+ compounds at temperatures required for catalysis. Encapsulated Re metal clusters formed by the reduction of Si‐OfReO3‐Al precursors led to CH4 pyrolysis and C3H8 dehydrocyclodimerization rates (per Re) that are higher than those previously reported for zeolite‐based catalysts. The rate of CH4 conversion to benzene, by using ReZSM5, was ≈30 % higher than that of the best reported catalysts, based on encapsulated MoCx clusters, whereas C2H4 and C6+ arene selectivities were similar. C3H8 activity and selectivity of ReZSM5 was significantly higher than that of GaZSM5, the best reported catalyst for these reactions. Reaction rates (per Re) were independent of the Re/Alf (Alf: aluminum framework) ratio for both Re and ReOx species. This is consistent with the uniform character of the structures formed during grafting of the ReOx species through sublimation and their ability to retain their homogeneity even after their reduction to encapsulated Re‐clusters.
Rearrangement of a (Dithiolato)platinum(II) Complex Formed by Reaction of Cyclic Disulfide 7,8‐Dithiabicyclo[4.2.1]nona‐2,4‐diene with a Platinum(0) Complex: Oxidation of the Rearranged (Dithiolato)platinum(II) Complex
Authors: Ishii Akihiko , Kashiura Satoshi , Hayashi Yuichi , Weigand Wolfgang
Published: February 2007

Reaction of the title bicyclic disulfide 16 with [(Ph3P)2Pt(η2‐C2H4)] (2) yielded the corresponding (dithiolato)platinum(II) complex 17 by oxidative addition. The initial product 17 isomerized at room temperature in a [1,5]‐sulfur rearrangement to give another (dithiolato)platinum(II) complex 18 in high isolated yield. Oxidation reactions of 18 with dimethyldioxirane (DMD) provided (sulfenato‐thiolato)platinum(II) 23, (sulfinato‐thiolato)platinum(II) 24, (sulfenato‐sulfinato)platinum(II) 25, and (disulfinato)platinum(II) 26 complexes, the structures of which were elucidated by NMR spectroscopy and X‐ray crystallography. The oxidation process took place regioselectively in the first step and chemoselectively in the second. The selectivities are discussed.
An Improved Catalyst System for the Iron‐Catalyzed Intermolecular Ring‐Expansion Reactions of Epoxides
Authors: Hilt Gerhard , Bolze Patrick , Harms Klaus
Published: February 2007

A considerable improvement is reported in the iron‐catalyzed ring‐expansion reactions of epoxides generating tetrahydrofuran derivatives by formal insertion of an alkene. Optimization of the catalyst system revealed that a preformed [Fe(salen)] complex minimizes the formation of polymerization side‐products so that increased yields of intermolecular reactions were obtained. However, more importantly, the scope of the reaction could also be enlarged considerably. The iron‐catalyzed ring‐expansion reaction can now be applied to some styrene oxide derivatives, acting as radical donors, as well as to a wide variety of acceptor‐substituted acyclic alkenes and cyclic dienes that act as radical acceptors. The use of unsymmetrical radical acceptors led to interesting questions concerning the regiochemistry of the reactions. The conservation of the stereochemistry of the starting materials in the products was investigated through a study of the reactions of E‐ and Z‐configured acceptor‐substituted double bonds. The reactions of fumaric and maleic esters were performed and the ratios of diastereomeric and regioisomeric products were determined.
Luminescent Nanocrystals for Nonenzymatic Glucose Concentration Determination
Authors: Wang Leyu , Li Yadong
Published: February 2007

By using a facile, wet‐chemical approach, luminescent LaF3:Ce3+/Tb3+ single‐crystal nanoparticles were prepared from nitrate and sodium fluoride precursors in a mixture of ethanol and ethylene glycol. These nanoparticles were functionalized with glucose. A novel fluorescence resonance energy transfer method for nonenzymatic glucose determination has been developed by using these glucose‐modified nanocrystals. Under the chosen conditions, concentrations of glucose between 0.5 and 25.0 mmol L−1 in aqueous solutions were successfully determined. Owing to their high luminescence and good dispersibility in water, these nanocrystals are also potential fluorescent biolabels for other biological and clinical applications, such as in fluorescence imaging and for immunoassays.
Coronary microvascular reactivity is only partially predicted by atherosclerosis risk factors or coronary artery disease in women evaluated for suspected ischemia: results from the NHLBI Women's Ischemia Syndrome Evaluation (WISE)
Authors: Wessel Timothy R. , Arant Christopher B. , McGorray Susan P. , Sharaf Barry L. , Reis Steven E. , Kerensky Richard A. , von Mering Gregory O. , Smith Karen M. , Pauly Daniel F. , Handberg Eileen M. , Mankad Sunil , Olson Marian B. , Johnson B. Delia , Bairey Merz C. Noel , Sopko George , Pepine Carl J.
Published: February 2007

Background

Altered coronary reactivity is frequent in women with findings of myocardial ischemia without significant obstructive disease. This suggests a defect in coronary microvascular function. The adenosine‐related component of this altered reactivity has been described in male and mixed gender populations, while the factors influencing this component of coronary reactivity in symptomatic women have received limited attention. Accordingly, the relationship between adenosine‐related microvascular coronary reactivity and risk factors in symptomatic women evaluated for suspected ischemia remains uncertain.

Hypothesis

Abnormal coronary microvascular reactivity to adenosine is predicted by atherosclerosis risk factors in women.

Methods

As part of the NHLBI‐sponsored Women's Ischemia Syndrome Evaluation (WISE), we investigated the relationship between risk factors and coronary microvascular reactivity as flow velocity reserve to intracoronary adenosine (CFVRAdo) in 210 women referred for angiography to evaluate suspected ischemia.

Results

Univariate analyses identified associations between CFVRAdo and multiple risk conditions; however, after adjusting for age, none remained significant. The best multivariable model using combinations of risk conditions to predict CFVRAdo yielded an R2 of only 0.18.

Conclusions

Among women with suspected ischemia, risk factors account for <20% of observed variability in CFVRAdo. Therefore, other as yet unidentified factors must primarily account for coronary microvascular reactivity to adenosine. Copyright © 2007 Wiley Periodicals, Inc.
Cardiac Syncope in Pediatric Patients
Authors: Massin Martial M. , Malekzadeh‐milani Sophie , Benatar Avram
Published: February 2007

Objective

To assess the epidemiology of cardiac syncope in children and evaluate the guidelines on its management.

Material and methods

We analyzed the etiology to syncope and diagnostic workup in consecutive pediatric patients presenting with syncope in our emergency departments or cardiac outpatient clinics between 1997 and 2005, and who were subsequently diagnosed as having cardiac syncope.

Results

A primary cardiac cause was identified in 11 syncopal patients presenting to the emergency room and 14 patients to the cardiac clinic: supraventricular tachyarrhythmia in 9, ventricular tachyarrhythmia in 10, pacemaker dysfunction in 2, and isolated cases of sick sinus syndrome, hypoxic spell, hypertrophic cardiomyopathy, and primary pulmonary hypertension. Some elements suggested potential cardiac disease as a cause of syncope in all cases. The resting electrocardiogram and the echocardiogram were interpreted as positive and relevant to the diagnosis in 17 and 3 patients, respectively. Exercise electrocardiogram and Holter recording provided diagnostic information previously not seen on the resting electrocardiogram in six and three patients, respectively. Three children have died and one child has neurological sequelae following resuscitation.

Conclusion

Our data support the premise that careful history taking with special focus on the events leading up to syncope, as well as a complete physical examination, can guide practitioners in discerning which syncopal children need further cardiac investigations. Copyright © 2007 Wiley Periodicals, Inc.
Spectral properties of a bifunctional PARACEST europium chelate: an intermediate for targeted imaging applications
Authors: Adair Christopher , Woods Mark , Zhao Piyu , Pasha Azhar , Winter Patrick M. , Lanza Gregory M. , Athey Phillip , Sherry A. Dean , Kiefer Garry E.
Published: February 2007

This report describes a preliminary study to investigate the effect of structural variations in a bifunctional ligand being developed for targeted PARACEST applications. Utilizing Eu‐DOTA‐4AmCE as the functional PARACEST core, a nitro‐aromatic functionality was incorporated to provide the point for conjugation. This intermediate possesses a coordinated water proton signal at 57 ppm which upon saturation produces a 22% decrease in bulk water signal intensity using 10 mM agent. Curve fitting analysis of the CEST spectrum to an exchange model based upon modified Bloch equations gave an estimate of 687 ± 100 µs for the bound water lifetime (τm). Although substantially longer than the 382 µs observed for the parent chelate structure, this water exchange rate remains in the necessary window to produce a significant CEST effect. These findings demonstrate the need to recognize the influence of bifunctional linkers on water exchange rates in lanthanide complexes of this type and the potential for using this functionality as a means of fine‐tuning PARACEST performance. Copyright © 2007 John Wiley & Sons, Ltd.
Diagnosis and management of chronic myeloid leukemia
Authors: Kantarjian Hagop M. , Cortes Jorge , Guilhot Francçois , Hochhaus Andreas , Baccarani Michele , Lokey Lee
Published: February 2007

BACKGROUND.

The success of imatinib therapy for chronic myeloid leukemia (CML) has brought new challenges; these include optimizing disease monitoring, imatinib resistance, and use of novel, more potent tyrosine kinase inhibitors. Thus, there is a need to establish new best practices for CML management in the post‐imatinib era.

METHODS.

An internet‐based questionnaire, consisting of 26 multiple choice questions, was developed to assess hematologists' and oncologists' self‐reported treatment strategies for CML.

RESULTS.

Between November 2005 and January 2006, 956 eligible physicians responded to the survey; 727 from the US and 229 from Europe. Most US respondents (60%) practiced in the community setting, whereas European respondents were primarily academic (44%) and hospital‐based (40%). Physicians' responses were generally in line with current recommendations, although differences were identified. Confusion existed among respondents over optimal timing of treatment decisions, with a notable proportion of physicians focusing on a single timepoint rather than consistent monitoring, as currently advocated. Some respondents were unaware of new molecular monitoring techniques, when to monitor for BCR‐ABL mutations (and the impact on treatment decisions), and the benefit of new tyrosine kinase inhibitors.

CONCLUSIONS.

Responses to the survey suggest that treatment practices in some areas of CML management are not in line with current recommendations. Identified areas of need should be targeted in future educational activities for the CML community. Cancer 2007. © 2007 American Cancer Society.
Catheter‐related bloodstream infections in hematology
Authors: Worth Leon J. , Slavin Monica A. , Brown Graham V. , Black James
Published: February 2007

Central venous catheters are essential in the management of many malignant disorders, but catheter‐related bloodstream infections (CR‐BSIs) are significant complications in terms of morbidity, mortality, and healthcare expenditure. These outcome measures are useful for monitoring of infection control practice and the effect of preventive strategies. Unlike intensive care unit (ICU) populations, surveillance for CR‐BSIs in the hematology population is not standardized, despite the potential value of detecting changes in rate, etiology, and changes in risk for infective complications in association with increasingly intensive chemotherapeutic regimens in this immunocompromised population. Essential components of a successful surveillance strategy include selection of a health outcome of significance, definition of goals of the surveillance system, involvement of key stakeholders in planning and development, application of valid case definitions, allocation of resources and trained personnel, risk stratification, and use of appropriate statistical methods for analysis. These are discussed with reference to patients with hematologic malignancy, together with review of previous surveillance strategies in this population. Only when these issues are addressed can a surveillance strategy reliably assess trends and compare data, leading to improved patient outcomes and a reduction in healthcare expenditure for patients with hematologic malignancy. Cancer 2007. © 2007 American Cancer Society.
Association between pharmaceutical involvement and outcomes in breast cancer clinical trials
Authors: Peppercorn Jeffrey , Blood Emily , Winer Eric , Partridge Ann
Published: February 2007

BACKGROUND.

Since 1992, pharmaceutical industry support has surpassed National Institutes of Health funding for clinical research in the United States. In this study, the authors sought to evaluate the impact of this shift in funding from public to private sponsors on the nature of published breast cancer clinical research.

METHODS.

All published breast cancer clinical trials from 2003, 1998, and 1993 were reviewed from 10 select English‐language medical journals to evaluate pharmaceutical involvement over time and the association between sponsorship, trial design, and results. Clinical studies that reported disease‐specific outcomes from medical therapy for breast cancer were eligible for analysis. Pharmaceutical involvement was defined as reported pharmaceutical industry funding, provision of drug, and/or authorship for each publication.

RESULTS.

In total, 140 eligible studies were identified, including 45 studies that were published in 1993, 39 studies that were published in 1998, and 56 studies that were published in 2003. Among those, 67 publications (48%) reported pharmaceutical industry involvement, 36 publications (26%) had at least ≥1 pharmaceutical industry author, And 100 publications (71%) were considered positive. Pharmaceutical involvement was identified in 44% of the studies published in 1993, in 38% of the studies published in 1998, and in 58% of the studies published in 2003. Pharmaceutical authorship was reported in 22% of the 1993 studies, in 21% of the 1998 studies, and in 34% of the 2003 studies. For studies that were published in 2003, those that reported pharmaceutical involvement were more likely to be positive (84% vs 54%; P = .02; Fisher exact test), to be single‐arm studies (66% vs 33%; P = .03), and to evaluate metastatic disease (72% vs 46%; P = .06).

CONCLUSIONS.

Pharmaceutical involvement in published clinical breast cancer research may affect study design, focus, and results. Further research is warranted, including analysis of unpublished studies, to evaluate the impact of increasing pharmaceutical industry involvement on clinical research. Cancer 2007;109:. © 2007 American Cancer Society.
Patient variables that predict atypical cytology by nipple duct lavage
Authors: Bushnaq Zinaida I. , Ashfaq Raheela , Leitch A. Marilyn , Euhus David
Published: February 2007

BACKGROUND.

Nipple duct lavage (NDL) may be useful for breast cancer risk stratification. Published guidelines recommend that women with a 5‐year Gail risk ≥1.7% should consider undergoing lavage for any fluid‐yielding ducts, but it is not known whether increased breast cancer risk or nipple fluid production predict lavage atypia.

METHODS.

One hundred fifty women unselected for breast cancer risk underwent NDL with cannulation of all nipple aspirate fluid (NAF)‐producing ducts and at least 1 dry duct. This resulted in 516 lavage samples. The rate of cytologic atypia was compared for NAF‐positive ducts and NAF‐negative ducts and for women with 5‐year Gail risks ≥1.7% and <1.7%. Ducts from breasts with cancer (N = 113) were excluded from the analysis.

RESULTS.

The cytologic atypia rate was similar for the 240 NAF‐producing ducts (19%) and the 163 dry ducts (15%; P = .36). No significant differences were observed when atypia was categorized as mild (13% vs 10%; P = .63) or marked (6% vs 4%; P = .53). Among the 83 patients who were unaffected by breast cancer, atypia was diagnosed in 15 of 44 patients (34%) with a 5‐year Gail risk <1.7% and in 11 of 39 patients (28%) with a 5‐year Gail risk ≥1.7% (P = .74).

CONCLUSIONS.

Neither NAF production nor 5‐year Gail risk predicted lavage atypia. Limiting NDL to fluid‐producing ducts in women with a 5‐year Gail risk ≥1.7% significantly reduced the sensitivity of the test for population screening. Cancer 2007. © 2007 American Cancer Society.
A prospective study of the impact of nasopharyngeal cancer and radiotherapy on the psychosocial condition of Chinese patients
Authors: Lee Peter W. H. , Kwan Tracy T. C. , Kwong Dora L. W. , Sham Jonathan S. T. , Pow Edmond H. N. , McMillan Anne S. , Au Gordon K. H.
Published: February 2007

BACKGROUND.

Radiotherapy (RT) promises optimistic results in the treatment of nasopharyngeal cancer (NPC). The objective of the current study was to map out prospectively the impact of NPC and RT on patients from diagnosis to 1 year posttreatment.

METHODS.

For this study, 67 Chinese patients (46 men and 21 women) with newly diagnosed stage I or II NPC who received primary RT were recruited. Physical and psychosocial adjustments were measured by using the Rotterdam Symptom Checklist, Beck Anxiety Inventory, Beck Depression Inventory, Perceived Stress Scale, and the 36‐item Short‐Form Health Survey (SF‐36). Semistructured clinical interviews were conducted at bimonthly intervals from pre‐RT to 1 year post‐RT.

RESULTS.

Physical and psychosocial adjustments were poorest from pre‐RT to the end of RT. Rapid improvements in all areas were noted in the first 2 months post‐RT and reached a plateau at around the 6th month. At 1 year, except for physical symptoms and perceived stress, patient measures recovered to their pre‐RT levels. At 1 year, patients had more physical complaints (P < .001) but less perceived stress (P = .002). The percentage of patients who expressed fear of dying dropped from 28% pre‐RT to 2% at 1 year. However, patients who expressed “fear of the worst happening” increased from 51% pre‐RT to 57% at 1 year.

CONCLUSIONS.

Different periods in treatment of NPC imposed different psychosocial demands on patients. The current results indicated that the period from diagnosis to 2‐month post‐RT was a high‐risk period both physically and emotionally. After treatment, most patients showed resilience despite persistent side effects of RT and successfully resumed their pretreatment level of functioning by the end of the year. Despite resuming a normal or near‐normal living, patients still noted a subdued fear of recurrence. Cancer 2007. © 2007 American Cancer Society.