bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water‐Soluble Electrostatic Complexes of C60‐Anchored Anionic Polymers and Cationic Porphyrins
Authors: Chu Chih‐Chien , Ho Tong‐Ing , Wang Leeyih 
Published: January 2007

AbstractThe preparation of novel highly water‐soluble electrostatic complexes from C60‐anchored multi‐armed poly(acrylic acid)s and cationic porphyrin derivatives was demonstrated. The UV‐vis absorption and photoluminescence (PL) of these complexes show that the absorption of soret band exhibits a remarkable red shift and the emission of the Q band indicates an apparent quenching effect in comparison with that of the parent cationic porphyrin. These results imply a remarkable ground state and excited state interaction between the porphyrin ring and the C60 moiety.magnified image
‘Click’ Chemistry in Polymer and Materials Science
Authors: Binder Wolfgang H. , Sachsenhofer Robert 
Published: January 2007

AbstractThe modification of polymers after the successful achievement of a polymerization process represents an important task in macromolecular science. Cycloaddition reactions, among them the metal catalyzed azide/alkyne ‘click’ reaction (a variation of the Huisgen 1,3‐dipolar cycloaddition reaction between terminal acetylenes and azides) represents an important contribution towards this endeavor. They combine high efficiency (usually above 95%) with a high tolerance of functional groups and solvents, as well as moderate reaction temperatures (25–70 °C). The present review assembles recent literature for applications of this reaction in the field of polymer science (linear polymers, dendrimers, gels) as well as the use of this and related reactions for surface modification on carbon nanotubes, fullerenes, and on solid substrates, and includes the authors own publications in this field. A number of references (>100) are included.magnified image
Poly(cyclooctene)s with Pendant Fluorescent and Phosphorescent Metal Complexes
Authors: Kimyonok Alpay , Weck Marcus 
Published: January 2007

AbstractPoly(cyclooctene)s with pendant Alq3 and fac‐Ir(ppy)3 were synthesized. Carbazole‐based comonomers were used to increase the solubility of the polymers and to transfer the energy into metal complexes. Excitation spectra of all polymers provided evidence of energy transfer. We established that the polymer backbone does not interfere with the optical properties of the metal complexes. All copolymers retained the optical properties of their small molecule metal complex analogs in solution and the solid state, making these polymers promising materials for potential electro‐optical applications.magnified image
Controlled Radical Polymerization of 2,3‐Epithiopropyl Methacrylate
Authors: Tebaldi de Sordi Marli Luiza , Ceschi Marco Antônio , Petzhold Cesar Liberato , Müller Axel H. E. 
Published: January 2007

AbstractWe report first results on the controlled radical polymerization of 2,3‐epithiopropyl methacrylate (ETMA) also known as thiiran‐2‐ylmethyl methacrylate. Reversible addition‐fragmentation chain transfer (RAFT) of ETMA was carried out in bulk and in solution, using AIBN as initiator and the chain transfer agents: cyanopropyl dithiobenzoate (CPDB) and cumyl dithiobenzoate (CDB). A linear increase of the number‐average molecular weight and decrease of the polydispersity with monomer conversion were observed using CPDB as transfer agent, indicating a controlled process. Atom transfer radical polymerization (ATRP) of ETMA was performed under different reaction conditions using copper bromide complexed by tertiary amine ligands and ethyl 2‐bromoisobutyrate (EBiB) or 2‐bromopropionitrile (BPN) as initiator. All experiments lead to a crosslinked polymer. Preliminary studies in the absence of initiator showed that the CuBr/ligand complex alone initiates the ring‐opening polymerization of thiirane leading to a poly(propylene sulfide) with pendant methacrylate groups.magnified image
Photoinduced Crosslinking of Polymers Containing Pendant Hydroxyl Groups by Using Bisbenzodioxinones
Authors: Kumbaraci Volkan , Talinli Naciye , Yagci Yusuf 
Published: January 2007

AbstractIn the present study, it has been demonstrated that polymers containing pendant hydroxyl groups can undergo photoinduced crosslinking upon irradiation in the presence of bifunctional benzodioxinone. Irradiation of the copolymers of 2‐hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) in dichloromethane and THF solutions or in films containing bisbenzodioxinone, namely 5‐[9‐(4‐oxo‐2,2‐diphenyl‐4H‐benzo[d][1,3]dioxin‐5‐yloxy) nonyloxy]‐2,2‐diphenyl‐4H‐benzo[d][1,3]dioxin‐4‐one resulted in the formation of insoluble networks. Model studies using monofunctional napthodioxinone, namely 7‐hydroxy‐2,2‐diphenyl‐4H‐naphtho[2,3‐d][1,3]dioxin‐4‐one, revealed that crosslinking occurs via inter‐chain ester formation between photochemically generated keten intermediates and pendant hydroxyl groups.magnified image
Fast Controlled Radical Polymerization of Styrene Mediated by Oligomeric Nitroxides Formed In Situ
Authors: Sciannamea Valérie , Catala Jean‐Marie , Jerome Robert , Detrembleur Christophe 
Published: January 2007

AbstractIn the presence of an oligomeric hindered secondary amine added with peracetic acid as the oxidant, radical polymerization of styrene is fast and controlled at 110 °C. Under these experimental conditions, an oligomeric nitroxide is formed in situ. This polymerization is 2.5 faster than polymerization mediated by the alkoxyamine derivated from TIPNO (2,2,5‐trimethyl‐4‐phenyl‐3‐azahexane‐3‐nitroxide), which generates a low molar mass nitroxide. Similarly, substitution of a low molar mass secondary amine, 2,2,6,6‐tetramethylpiperidone (4‐oxo‐TMP), for the oligomeric secondary amine maintains the control on the polymerization, which is however 4.6 times slower, all the other conditions being the same. The in situ formation of the oligomeric nitroxide has been confirmed by electron spin resonance (ESR).magnified image
Investigation and Modeling of Temperature Dependence Recovery Behavior of Shape‐Memory Crosslinked Polyethylene
Authors: Khonakdar Hossein Ali , Jafari Seyed Hassan , Rasouli Sorour , Morshedian Jalil , Abedini Hossein 
Published: January 2007

AbstractShape memory was induced in crosslinked low‐density polyethylene by a heating‐stretching‐cooling cycle. The effect of crosslink content on thermal properties and temperature dependence recovery behavior was studied experimentally. The importance of stretching temperature and crosslink content on recovery behavior could be reasonably explained by the observed changes in the thermal properties which were attributed to the differences in crystalline structures and mechanism of crystal formation during the heating‐stretching‐cooling process. A mechanical model was developed to describe qualitatively and quantitatively the temperature dependence recovery behavior of the prepared shape memory crosslinked polyethylene at nonisothermal state under various conditions by driving constitutive equations using a set of model constants. These model constants were determined with the help of a set of optimization codes using a genetic algorithm method. By choosing a suitable set of model constants one can describe with high accuracy the temperature dependence recovery behavior of any shape memory polymer.magnified image
Ternary Polymer Solutions with Hydrogen Bonds, 1
Authors: Soria Vicente , Figueruelo Juan E. , Gómez Clara M. , Abad Concepción , Campos Agustín 
Published: January 2007

AbstractThe Flory Huggins methodology coupled to AET has been extended to ternary polymer systems, in particular to solvent (A)/polymer 1 (B)/polymer 2 (C) systems, with the two polymers displaying H‐bonding interactions. Because the H‐bonding can perturb the randomness of polymeric conformations, the change in Gibbs free energy of mixing, ΔG, should arise from changes in combinatorial entropy as well as in interaction energy. The combinatorial part of ΔG is evaluated through AET as a function of the association constant η between B and C components, the autoassociation constant σ between B components, and the independent number m of interaction sites of acceptor C. The enthalpic contribution is evaluated by introducing concentration independent interaction parameters, $g'_{ij}$, evaluated by subtracting from the functions gij(ϕ) the energetic contributions due to the H‐bonding specific interactions. Once the resulting ΔG equation is tested, values obtained for hypothetic systems with low, moderate and strong H‐bonding interactions are discussed.magnified image
Ternary Polymer Solutions with Hydrogen Bonds, 2
Authors: Figueruelo Juan E. , Monzó Isidro S. , Gómez Clara M. , Soria Vicente , Abad Concepción , Campos Agustín 
Published: January 2007

AbstractExperimental ternary phase diagrams for ternary systems CHL/PS‐MAA/PVPy with diverse MAA contents have been determined by GPC. The presence of MAA in the copolymers gives rise to specific interactions, by hydrogen bond formation between both polymeric components, so strong that the isotherm for the system with the highest MAA content so far studied, CHL/PS‐MAA(8%)/PVPy, is representative of a complex coacervation situation. By applying the theoretical background deduced by coupling the Flory‐Huggins lattice model to the AET developed for ternary polymeric systems SPP with specific intermolecular interactions (via hydrogen bonds), free energy surfaces for the CHL/PS‐MAA/PVPy systems are constructed. From these plots theoretical ternary phase diagrams are deduced and a fair agreement with those obtained experimentally is observed.magnified image
Adsorption of Semiflexible Chains on Nanostriped Surfaces: Monte Carlo Simulations
Authors: AlSunaidi Abdullah 
Published: January 2007

AbstractMonte Carlo simulations were carried out to investigate the adsorption of semiflexible chains from a semidilute solution to substrates with periodic stripes of width w. The chains are made of fused N = 10 monomers of diameter σ interacting with each other through excluded volume interactions and with the stripes via a square‐well potential of depth ε and width σ. The surface coverage was found to increase upon increasing the chain stiffness and decreases on increasing the width of the stripes. At small w, more flexible chains are adsorbed than stiff chains. Analysis of the radius of gyration for the chains showed that when w < 8σ, the component along the stripe direction is significantly larger than the others. Orientational order parameter reveals that, for small w, chains have preference to align along the stripe direction.magnified image
Chain Length Distributions of Polyolefins Made with Coordination Catalysts at Very Short Polymerization Times – Analytical Solution and Monte Carlo Simulation
Authors: Soares João B. P. , Hamielec Archie E. 
Published: January 2007

AbstractWe developed an analytical solution to describe how the CLD of polymers made with coordination polymerization catalysts vary as a function of time for very short polymerization times before the CLD becomes completely developed. We compared the analytical solution with a dynamic Monte Carlo model for validation, obtaining excellent agreement. Our analytical solution can be used to determine when the steady‐state hypothesis, commonly used in polymerization models, becomes valid as a function of polymer chain length. We also extended our model to describe polymerization with multiple‐site‐type catalysts. Depending on the polymerization kinetic parameters of the different site types on the catalyst, the fully developed CLD is reached through very different intermediate CLDs. This modeling approach, although rather simplified, can be used to interpret results from short polymerization time experiments such as the ones done in stopped‐flow reactors.magnified image
Dynamic Monte Carlo Simulation of ATRP with Bifunctional Initiators
Authors: Al‐Harthi Mamdouh , Soares João B. P. , Simon Leonardo C. 
Published: January 2007

AbstractA dynamic Monte Carlo model was developed to simulate ATRP with bifunctional initiators in a batch reactor. Model probabilities were calculated from polymerization kinetic parameters and reactor conditions. The model was used to predict monomer conversion, average molecular weight, polydispersity and the complete CLD as a function of polymerization time. The Monte Carlo model was compared with simulation results from a mathematical model that uses population balances and the method of moments. We also compared polymerizations with monofunctional and bifunctional initiators to illustrate some of the advantages of using bifunctional initiators in ATRP. In addition, we used the model to investigate the effect of the control volume and several polymerization conditions on simulation time, monomer conversion, molecular weight averages and CLD. Our results indicate that computational times can be reduced without sacrificing the quality of the results if we run several simulations with small control volumes rather than one single simulation with a large control volume.
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Preparation of Polymer‐Metal Composites via In Situ Decomposition of Metal Salts by Frontal Polymerization
Authors: Barany Zsolt Bela , Nagy Istvan Peter , Lovrity Zita , Gacsi Zoltan 
Published: January 2007

AbstractComposites containing powdered zinc, and zinc/lead acetate were prepared via frontal polymerization. In the case of the acetates, elemental metal was formed in an in situ decomposition process. The local area function was used to demonstrate the distribution of fillers, and the uniformity of the area fraction for the quantitative characterization of the distribution. With the use of metal acetates, composites of uniform metal distribution can be produced, unlike in systems with metal powder, where the metal particles are enriched at the margin of the sample. It can be established that the specific direct‐current resistance significantly decreases in AA‐TGDMA composites by the addition of zinc acetate, compared to that of the initial monomer mixture. On heating, the unreacted zinc acetate decomposes further, which results in the further decrease in electrical resistance.magnified image
Continuous Bulk Process for the Production of High‐Impact Polystyrene: Recent Developments in Modeling and Control
Authors: Meira Gregorio R. , Luciani Carla V. , Estenoz Diana A. 
Published: January 2007

AbstractThis work presents (in a wider perspective), some of our recent developments in the mathematical modeling and control of bulk polymerization for the production of HIPS. The recent model by Casís assumes the polymerization to be heterogeneous, and it calculates (in two phases) the global molecular structure of the three polymeric components of HIPS (free polystyrene, unreacted polybutadiene, and graft copolymer). At present, a model is being developed capable of estimating the average particle morphology (salami or core‐shell). Assuming a continuous bulk HIPS process as homogeneous, Luciani estimated the evolution of the MFI of the final product during changes of grade, with the aim of minimizing the intermediate off‐spec product. Finally, an unpublished simulation is presented that describes the transitions between the steady state of a HIPS‐grade and that of a general‐purpose polystyrene.magnified image
EBV+ lymphoproliferative disease following prolonged chemotherapy for refractory LCH
Authors: Lee Dean A. , Tatevian Nina , Herring Ruth A. , McClain Kenneth L. 
Published: January 2007

AbstractEpstein–Barr virus (EBV) is a herpesvirus for which latent infection in B lymphocytes occurs in most individuals by middle childhood. Clinically significant reactivation of this virus occurs in the context of suppressed cell‐mediated immunity, occasionally developing into lymphoproliferative disease (EBV‐LPD). EBV reactivation is rarely associated with intensive chemotherapy alone. Here we present the case of a 4‐year‐old female who developed EBV‐LPD as a complication of prolonged immunosuppressive chemotherapy for her multiply‐recurrent Langerhans cell histiocytosis (LCH). Pediatr Blood Cancer 2008;50:728–730. © 2007 Wiley‐Liss, Inc.
Markers of bone turnover are associated with growth and development in young subjects with sickle cell anemia
Authors: Fung Ellen B. , Kawchak Deborah A. , Zemel Babette S. , Rovner Alisha J. , Ohene‐Frempong Kwaku , Stallings Virginia A. 
Published: January 2007

AbstractChildren with sickle cell anemia (SCA) have low bone mass though bone turnover has not been well described. In this study, growth and pubertal development were assessed twice, 1 year apart, in 80 young subjects with type‐SS SCA, while whole body bone mineral content (BMC) and density where measured in a subset (n = 46). Markers of bone turnover were measured at the second visit. Bone formation (alkaline phosphatase) was elevated, whereas bone resorption (deoxypryidinoline) was decreased compared to published data in healthy children. Markers of bone turnover correlated with growth velocity and pubertal development but not with changes in bone mass. Pediatr Blood Cancer 2008;50:620–623. © 2007 Wiley‐Liss, Inc.
Elevated maternal second‐trimester serum alpha‐fetoprotein as a risk factor for placental abruption
Authors: Tikkanen Minna , Hämäläinen Esa , Nuutila Mika , Paavonen Jorma , Ylikorkala Olavi , Hiilesmaa Vilho 
Published: January 2007

AbstractObjectiveTo analyze the association of second‐trimester maternal serum alpha‐fetoprotein (MSAFP) and free beta human chorionic gonadotrophin (MSβ‐hCG) levels to placental abruption.MethodsFifty‐seven women with placental abruption and 108 control women without placental abruption were tested for second‐trimester MSAFP and MSβ‐hCG levels as a part of a trisomy 21 screening program. Discriminatory cutoff levels for MSAFP were sought to predict placental abruption.ResultsThe median of the MSAFP multiples of median (MoM) (1.21) was significantly higher in the abruption group than in the control group (1.07) (p = 0.004). In multivariate analysis, elevated MSAFP remained an independent risk factor for placental abruption when adjusting for other risk factors (parity ≥ 3, smoking, previous placental abruption, preeclampsia, bleeding in II or III trimester, and placenta previa). MSAFP ≥ 1.5 MoM had a sensitivity of 29% and a false‐positive rate of 10%. The levels of the MSβ‐hCG MoM did not differ between the cases and the controls.ConclusionAlthough second‐trimester MSAFP levels are higher in women with subsequent placental abruption, the clinical usefulness of this test is limited due to low sensitivity and high false‐positive rate. Copyright © 2007 John Wiley & Sons, Ltd.
Formation of Highly Releasing PET Surfaces by Atmospheric Pressure Glow Plasma Fluorination and Surface Roughening
Authors: Masutani Yasushi , Nagai Nodoka , Fujita Shiro , Hayashi Masushi , Kogoma Masuhiro , Tanaka Kunihito 
Published: January 2007

AbstractCombined surface treatments using plasma fluorination and surface roughening were applied to investigate whether they could increase the peel property of PET beyond the value needed for use as a release coating of pressure‐sensitive adhesive tapes. The peel strength of PET treated with CF4/He APG plasmas decreased to approximately 100 N · m−1, but not quite to the ideal value of PTFE, 20 N · m−1. We also prepared PET with a rough surface (matte PET) to examine the effect of surface roughening. The matte PET peel strengths were decreased by plasma fluorination; the roughest matte PET showed even lower peel strength than PTFE. We conclude that the combined treatments could be effective in the formation of a surface with high peel property on PET.magnified image
Proteomics analysis of cellular components in lentiviral vector production using Gel‐LC‐MS/MS
Authors: Wheeler Jun X. , Jones Christopher , Thorpe Robin , Zhao Yuan 
Published: January 2007

AbstractAmong the gene therapy vectors developed to date, lentiviral vectors persist in the host and are therefore best suited for long‐term gene transfer and gene‐replacement therapies. Human immunodeficiency virus (HIV)‐1‐based lentiviral vector products are currently produced by transient transfection, filtration and ultracentrifugation, and the quality of the resultant vector product is variable. We reason that by identifying host proteins co‐produced with viral vectors we may better understand the mechanism of viral vector production, and improve the safety and quality of the resultant products. Our LC‐MS/MS studies identified both viral vector proteins and host proteins, including nuclear proteins, elongation factors and chaperone and heat shock proteins (HSP), and confirmed the presence of known HIV‐incorporated proteins, e.g. elongation factor‐1α, HSP70 and Histone 2A, demonstrating the capability and viability of LC‐MS/MS methods for the proteomic analysis of highly complex samples. Evaluation of the functions of the identified components is in progress to understand their implication for product quality and safety. These studies support the development of improved production and characterisation methods and advance the clinical application of lentiviral vector‐based products.
Expression of tropomyosin alpha 4 chain is increased in esophageal squamous cell carcinoma as evidenced by proteomic profiling by two‐dimensional electrophoresis and liquid chromatography‐mass spectrometry/mass spectrometry
Authors: Harada Toshio , Kuramitsu Yasuhiro , Makino Akira , Fujimoto Masanori , Iizuka Norio , Hoshii Yoshinobu , Takashima Motonari , Tamesa Michiko , Nishimura Taku , Takeda Shigeru , Abe Toshihiro , Yoshino Shigefumi , Oka Masaaki , Nakamura Kazuyuki 
Published: January 2007

AbstractTo identify proteins associated with esophageal carcinogenesis, we performed protein profiling of 16 esophageal squamous cell carcinomas (ESCCs) and paired noncancerous tissues by 2‐DE and MS/MS. In cancerous tissues, three spots showed significant up‐regulation in the amount of protein, while eight spots were significantly down‐regulated. The identities of the spots were determined by PMF with LC‐MS/MS and were confirmed by immunoblotting. The up‐regulated proteins were tropomyosin alpha 4 chain, transgelin, and pyruvate kinase. The down‐regulated proteins were serum albumin precursor, isoforms of annexin A1, tropomyosin beta chain, 14‐3‐3 protein sigma, and isoforms of serotransferrin precursor. In all 16 cases, up‐regulation of the tropomyosin alpha 4 chain was confirmed by immunoblotting. Localization of the tropomyosin alpha 4 chain in ESCC cells and adjacent fibroblasts was confirmed by immunohistochemistry.
Robotic pyeloplasty: a critical appraisal
Authors: Badwan K. , Bhayani S. 
Published: January 2007

AbstractBackgroundLaparoscopic pyeolplasty has become a minimally invasive alternative to open pyeloplasty. Due to technical concerns with intracorporeal suturing, robotic pyeloplasty has become an emerging alternative.MethodsThe literature was reviewed for reports and outcomes on robotic pyeloplasty.ResultsReports of robotic pyeloplasty are increasing, and outcomes appear excellent.ConclusionsRobotic pyeloplasty is feasible with excellent outcomes. Challenges remain in making the procedure cost effective. Copyright © 2007 John Wiley & Sons, Ltd.