bluuebunny/crossref_metadata_2025_split huggingface dataset:
Imaging myocardial fiber disarray and intramural strain hypokinesis in hypertrophic cardiomyopathy with MRI
Authors: Tseng Wen‐Yih I. , Dou Jiangang , Reese Timothy G. , Wedeen Van J. 
Published: December 2005

AbstractPurposeTo examine the relationship between myofiber disarray and myocardial hypokinesis in human hypertrophic cardiomyopathy (HCM) using noninvasive cardiac diffusion and strain MRI.Materials and MethodsFive patients with a diagnosis of HCM and five age‐matched healthy volunteers were studied and compared. Cardiac diffusion MRI was applied to map in vivo myocardial fiber architecture. Cardiac strain MRI was applied to map myocardial motion. By acquiring registered diffusion and strain MRI images in vivo on both normal and HCM hearts, we investigated in HCM the relationship between myofiber disarray and systolic strain components, including radial, fiber, and cross‐fiber strains, and sought to determine the mechanism behind disarray‐related myocardial dysfunction in HCM.ResultsRegionally disordered fiber orientation and reduced diffusion fractional anisotropy (FA) were found in HCM, demonstrating myofiber disarray. Intramural myocardial strain hypokinesis (reduced radial, fiber, and cross‐fiber strains) was also observed in HCM in the same region, and was found to be correlated with FA. The correlation between FA and hypokinesis was found to be stronger in the cross‐fiber direction (part of the passive myocardial function) compared to the fiber direction (part of the active myocardial function). This is consistent with the hypothesis that the principal feature of HCM is the reduction of myocardium passive compliance. The angle between principal shortening and fiber orientation was markedly disordered in HCM, indicating an abnormal transmural coupling.ConclusionMyofiber disarray in HCM is correlated with abnormalities of both passive and active myocardial function, and the normal patterns of fiber shortening and wall thickening are deranged in HCM. J. Magn. Reson. Imaging 2006. © 2005 Wiley‐Liss, Inc.
Chemistry of Siloxane Amide as a New Curing Agent for Epoxy Resins: Material Characterization and Properties
Authors: Srividhya Marimuthu , Lakshmi Madurai Suguna , Reddy Boreddy Sivarami R. 
Published: December 2005

AbstractSummary: A novel amine terminated elastomeric siloxane modifier (SA amine) for epoxy networks has been synthesized and characterized. The dual role of SA amine not only as a curing agent and but also as a toughener was studied. Curing studies of conventionally available epoxy resin, diglycidyl ether of bisphenol A (DGEBA) using SA amine along with diamino diphenyl sulfone (DDS) has been carried out. An interesting feature was the complete miscibility of the siloxane oligomer with DGEBA. In addition, the cured laminates were analyzed for thermal, mechanical, and surface morphology and also for their chemical resistance. The thermo mechanical properties were studied using dynamic mechanical analysis. The modified systems showed very high thermal stability. A single glass transition temperature was observed for the modified systems. The moisture resistance of the samples improved notably with the introduction of siloxane into the systems. The modified systems also improved the impact strength of the materials to a greater extent (35–50%) even though there was a small decrease in their tensile properties (12%). The system with maximum SA amine content showed the higher impact strength value and also a higher thermal stability without any phase separation in the morphology.Representation of the crosslinking pattern of the resin systems.magnified imageRepresentation of the crosslinking pattern of the resin systems.
Selective Removal of Dilute Benzene from Water by Various Cross‐Linked Poly(dimethylsiloxane) Membranes Containing tert‐Butylcalix[4]arene
Authors: Ohshima Tadahiro , Miyata Takashi , Uragami Tadashi 
Published: December 2005

AbstractSummary: This paper focuses on the addition of tert‐butylcalix[4]arene (CA) to cross‐linked poly(dimethylsiloxane) (PDMS) membranes derived from poly(dimethylsiloxane) di(methyl methacrylate) macromonomer (PDMSDMMA) and various divinyl cross‐linker compounds, on the pervaporation characteristics for the removal of dilute benzene from an aqueous solution. When an aqueous solution of 0.05 wt.‐% benzene was permeated through the cross‐linked PDMSDMMA membranes containing CA they showed high benzene/water selectivity and permeability. Both the benzene/water selectivity and permeability of the membranes were enhanced by increasing both the divinyl compound cross‐linker content and the amount of CA, and were significantly influenced by the type of divinyl compound. Addition of CA to PDMSDMMA membranes cross‐linked with divinylperfluorohexane (DVF) showed the best pervaporation performance. The normalized permeation rate, benzene/water separation factor, and pervaporation separation index of these membranes were 1.86 × 10−5 kg · m/(m2 · h), 5 027, and 9 350, respectively. The pervaporation characteristics of the cross‐linked PDMSDMMA membranes containing CA were studied with respect to their chemical and physical structure. Furthermore, the mechanism of the selective permeation of benzene over water through these membranes was investigated.
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Novel Metal‐Containing Polyurethane Elastomers Prepared Using Tetradentate Schiff Base Metal Complexes
Authors: Senthilkumar Natarajan , Raghavan A. , Nasar A. Sultan 
Published: December 2005

AbstractSummary: A series of divalent metal (Co2+, Ni2+, Cu2+)‐incorporated tetradentate Schiff base complexes of the generic name 1,2‐bis[{4‐(2‐hydroxy)ethoxy‐2‐hydroxyphenyl}methyl ketimino]ethane‐metal(II) (BHEHPMKE‐M)—metal‐containing dihydroxy monomers—were synthesized and characterized by UV‐visible, FT‐IR, MS, and atomic absorption spectroscopies and elemental analysis. Structure of one of the monomers was also confirmed by single‐crystal X‐ray diffraction technique. Several metal‐containing polyurethanes were prepared using these dihydroxy compounds and 1,4‐butanediol as chain extenders for prepolymers based on poly(oxytetramethylene) glycol‐2000 (PTMG‐2000) and 4,4′‐methylene bis(phenyl isocyanate) (MDI). The amount of metal‐containing monomer was varied from 0 to 1 equivalent to find the influence of the metal‐incorporated tetradentate Schiff base segment on thermal and mechanical properties of polyurethanes. The properties of metal‐containing polyurethanes were compared with those prepared using 1,4‐butanediol and 1,2‐bis[{4‐(2‐hydroxy)ethoxy phenyl}methyl ketimino]ethane—a diol without metal—as chain extenders. The polymers were characterized by FT‐IR, GPC, DSC, TGA, viscosity, and solubility measurements. The glass transition temperature (Tg) of the polyurethane prepared from the Schiff base diol (without metal) was found to increase when used alone as chain extender. Thermal and mechanical properties of polyurethanes were also found to improve markedly by the introduction of metal‐incorporated tetradentate Schiff base moiety into the polymer chain. The viscosity of the metal‐containing polyurethane decreased abruptly upon increasing the metal content.A series of polyurethanes derived from novel divalent metal (Co2+, Ni2+, Cu2+)‐incorporated tetradentate Schiff base complexes.magnified imageA series of polyurethanes derived from novel divalent metal (Co2+, Ni2+, Cu2+)‐incorporated tetradentate Schiff base complexes.
Nanoporous SiLK® Dielectric Films Prepared from Free‐Radical Graft Polymerization and Thermolysis
Authors: Chen Yiwang , Chen Lie , Wang Xiaofeng , He Xiaohui 
Published: December 2005

AbstractSummary: Thermally‐initiated free‐radical graft polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) with the ozone‐pretreated SiLK® precursor was carried out. The chemical composition and structure of the graft copolymers were characterized by NMR and X‐ray photoelectron spectroscopy (XPS). Nanoporous low dielectric constant (κ) SiLK films were prepared by solution spin‐casting of the graft copolymers on the Si(100) substrates, followed by thermally‐induced cycloaddition and cross‐linking of the SiLK precursor and thermal decomposition of the labile PEGMA side chains. The nanoporous SiLK films so‐obtained had well‐preserved SiLK backbones and pore size in the range of 10–15 nm. The refractive index (RI) of resulting films has decreased to 1.47, from 1.62 for the pristine (non‐porous) SiLK dielectric film. A dielectric constant of about 2.2 was achieved from thermolysis of the SiLK graft copolymer containing about 15.2 wt.‐% of the PEGMA side chains.Preparation of the nanoporous SiLK dielectric film.magnified imagePreparation of the nanoporous SiLK dielectric film.
Preparation of Fluorescent Carboxyl and Amino Functionalized Polystyrene Particles by Miniemulsion Polymerization as Markers for Cells
Authors: Holzapfel Verena , Musyanovych Anna , Landfester Katharina , Lorenz Myriam Ricarda , Mailänder Volker 
Published: December 2005

AbstractSummary: A series of fluorescent polystyrene latex particles with carboxyl and amino functionalities on their surface were synthesized by the miniemulsion technique. The fluorescent dye N‐(2,6‐diisopropylphenyl)perylene‐3,4‐dicarboximide (PMI) was incorporated into the copolymer nanoparticles formulated from styrene and acrylic acid or styrene and aminoethyl methacrylate hydrochloride. The resulting latexes were stable and showed a monodisperse size distribution. The particle size depended on the amount and nature of the functional comonomer and was in the range 100–175 nm. All latexes were characterized by transmission electron microscopy (TEM), dynamic light scattering, UV‐Vis spectroscopy and zeta potential measurements. The amount of surface functional groups was determined by electrolyte titration. Furthermore, the functionalized fluorescent particles were utilized as markers for HeLa cells and cell uptake was visualized using fluorescence microscopy. The correlation of the uptake of nanoparticles with the surface charge was determined by FACS measurements.Confocal fluorescent microscopy of HeLa cells after the uptake of amino functionalized particles (green).magnified imageConfocal fluorescent microscopy of HeLa cells after the uptake of amino functionalized particles (green).
Organic Montmorillonite as a Substitute for Aerosilica in Addition‐Type Liquid Silicone Rubber Systems
Authors: Wang Jincheng , Chen Yuehui , Jin Qiqi 
Published: December 2005

AbstractSummary: A novel addition‐type liquid silicone rubber (SR)/organic montmorillonite (OMMT) nanocomposite has been synthesized. N,N‐Di(2‐hydroxyethyl)‐N‐dodecyl‐N‐methylammonium chloride was used as an intercalation agent to treat Na+‐montmorillonite and form a novel kind of OMMT. Three types of SR/OMMT composites were synthesized with different amounts of OMMT, and were compared with an aerosilica‐modified SR system. Tensile strength, and other properties determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), were compared. A combination of Fourier‐transform infrared (FT‐IR) spectroscopy, wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electronic microscopy (TEM) studies showed that SR/OMMT composites were on the nanometer scale, and the segmented structure of the SR was disrupted by the presence of OMMT, as a result of the reaction between the monomer and the intercalation agent. Results showed that the physical and mechanical properties of an SR system with 1 phr of OMMT were nearly equal to that of an SR system with 3 phr of aerosilica because of the exfoliation of the OMMT and the resultant nano‐effect in the system.WAXD spectra of the organic montmorillonite (OMMT)‐intercalated silicone rubbermagnified imageWAXD spectra of the organic montmorillonite (OMMT)‐intercalated silicone rubber
Aliphatic Hyperbranched Copolyesters by Combination of ROP and AB2‐Polycondensation
Authors: Smet Mario , Gottschalk Carsten , Skaria Sunny , Frey Holger 
Published: December 2005

AbstractSummary: Hyperbranched aliphatic copolyesters have been prepared by the copolymerization of ε‐caprolactone and 2,2‐bis(hydroxymethyl)butyric acid (AB2‐monomer), catalyzed by (i) HfCl4(THF)2 and (ii) diphenylammonium trifluoromethanesulfonate (DPAT), respectively. In both cases, copolymerization by combined ROP/AB2‐polycondensation was achieved. The degree of branching (DB) and consequently the density of functional groups of the resulting copolyesters were controlled by the comonomer ratio in the feed. Molecular weights in the range $\overline M _{\rm n}$ = 22 000–166 000 g · mol−1 (GPC, PS standards) were obtained, with apparent polydispersity indices of 1.20 to 1.95. The DB was in the range 0.03–0.35. Remarkably, HfCl4(THF)2 appeared to cause no transesterification of the ester bonds in the hyperbranched polymer formed. Further esterification or functionalization of the hydroxyl end groups of the hyperbranched polymers is therefore possible in a convenient two step/one pot process. The prepared hyperbranched polycaprolactones can be used as multifunctional initiators for the ROP of ε‐caprolactone, which is also catalyzed by HfCl4(THF)2, resulting in multi‐arm star polymers. Diphenylammonium trifluoromethanesulfonate (DPAT) was also found to catalyze the combination of ROP and AB2 polycondensation. However, the applicability of this system is restricted due to side reactions that can lead to crosslinking.Synthesis of hyperbranched copolyesters by combined ROP/polycondensation.magnified imageSynthesis of hyperbranched copolyesters by combined ROP/polycondensation.
Dissipative Particle Dynamics Simulation of Microphase Separation and Properties of Linear–Dendritic Diblock Copolymer Melts under Steady Shear Flow
Authors: Liu Dahuan , Zhong Chongli 
Published: December 2005

AbstractSummary:Dissipative particle dynamic simulations were performed on the microphase separation, end‐to‐end distance, and shear viscosity of linear–dendritic diblock copolymers under steady shear flow. The results show that their microstructure and properties depend on both the shear rate and the degree of branching, and they can incorporate the characteristics of both linear and dendritic polymers to lead to new materials with unique properties.Schematic structure for the linear‐dendritic copolymer G4 described in this work.imageSchematic structure for the linear‐dendritic copolymer G4 described in this work.
Predicting the Morphology of Metallo‐Supramolecular Block Copolymers with Bulky Counter Ions
Authors: Kyrylyuk Andriy V. , Lohmeijer Bas G. G. , Schubert Ulrich S. 
Published: December 2005

AbstractSummary: The phase behavior of metallo‐supramolecular block copolymers with bulky counter ions is theoretically studied within the framework of a mean‐field dynamic density functional theory and compared with recent experiments on a polystyrene–poly(ethylene oxide) metallo‐supramolecular diblock copolymer, PS20‐[Ru]‐PEO70, with tetraphenylborate counter ions. The copolymer is modeled as a triblock polyelectrolyte, in which the metal complex is treated as the polyelectrolyte block. The topology and kinetics of the formation of the observed three‐domain lamellar morphology in which the polyelectrolyte blocks and bulky counter ions are located together to form electroneutral complexes, are in good agreement with experimental results. In addition, the model predicts the existence of core–shell morphologies. The agreement with and variations from the experimental phase diagram are discussed in detail.Morphological transformations in a metallo‐supramolecular block copolymer with bulky counter ions upon increasing the temperature.imageMorphological transformations in a metallo‐supramolecular block copolymer with bulky counter ions upon increasing the temperature.
Use of Coptidis Rhizoma and foetal growth: a follow‐up study of 9895 pregnancies
Authors: Chuang Chao‐Hua , Lai Jung‐Nien , Wang Jung‐Der , Chang Pei‐Jen , Chen Pau‐Chung 
Published: December 2005

AbstractPurposeTo explore the effect of Coptidis Rhizoma on foetal growth in pregnancy.MethodsDuring 1985–1987, each pregnant woman with 26 or more weeks of gestation who came to the Taipei Municipal Maternal and Child Hospital for prenatal care was enrolled and interviewed by three trained interviewers using structured questionnaires to obtain detailed information including the herbal medicines used during pregnancy. Medical histories of diabetes, hypertension, antepartum haemorrhage and medicines used during pregnancy were abstracted from medical records of mothers'. Data of birth weight, gestational duration and characteristics of infants were gathered from the Taiwan national birth registration. A total of 9895 singleton livebirths were analysed. The variables related to foetal growth included two dichotomous measures: low birth weight (LBW) and small for gestational age (SGA); and one continuous measure: birth weight. Potential risk factors associated with these outcomes were investigated using multiple logistic and linear regression models.ResultsAfter adjustment, pregnant women taking Coptidis Rhizoma during pregnancy had no significantly adverse effect on foetal growth. There was a non‐significantly slightly decreased mean of birth weight and increased risk of LBW and SGA babies if the frequency of using Coptidis Rhizoma was more than 56 times.ConclusionsThe usual usage of Coptidis Rhizoma during pregnancy seemed not to increase the adverse risk on foetal growth. Future observations for use of longer than 56 times or a higher cumulated dose were needed to clarify the safety. Copyright © 2005 John Wiley & Sons, Ltd.
Predictive factors of the number and the dose of anti‐psychotics in a cohort of schizophrenic patients
Authors: Lukasiewicz Michael , Gasquet Isabelle , Casadebaig Francoise , Philippe Alain , Ledoux Sylvie , Reynaud Michel , Falissard Bruno 
Published: December 2005

AbstractBackgroundAnti‐psychotic prescription in schizophrenia is characterised in Europe by frequent associations and high doses. Nevertheless, few longitudinal epidemiological studies have explored anti‐psychotic prescriptions.Aim(1) To describe the evolution of prescription patterns across time; (2) to determine risk factors for prescription of high doses of anti‐psychotics and for anti‐psychotic combinations.Materials and MethodsThree thousand four hundred seventy three subjects were included in 1993. Data collected in 1993 and subsequently in 1996 and 1999, provided information on demographics, clinical status and prescription. In 1996, the response rate was 68.5% and 56.7% in 1999.ResultsThe number of anti‐psychotics prescribed slightly decreased across time, while doses remained high for one‐third of the patients. The factors predicting dose were: dose at previous evaluation, class of anti‐psychotic and clinical severity. The factors predicting the number of anti‐psychotics were: previous number and class of anti‐psychotic and clinical severity.ConclusionHigher dosage and combinations were related more to physicians' habits than to patient characteristics, as is frequently observed in chronic disease. Copyright © 2005 John Wiley & Sons, Ltd.
Effects of the reaction parameters on the properties of thermosensitive poly(N‐isopropylacrylamide) microspheres prepared by precipitation and dispersion polymerization
Authors: Macková Hana , Horák Daniel 
Published: December 2005

AbstractPoly(N‐isopropylacrylamide) (PNIPAAm)‐based microspheres were prepared by precipitation and dispersion polymerization. The effects of several reaction parameters, such as the type and concentration of the crosslinker (N,N′‐methylenebisacrylamide or ethylene dimethacrylate), medium polarity, concentration of the monomer and initiator, and polymerization temperature, on the properties were examined. The hydrogel microspheres were characterized in terms of their chemical structure, size and size distribution, and morphological and temperature‐induced swelling properties. A decrease in the particle size was observed with increasing polarity of the reaction medium or increasing concentration of poly(N‐vinylpyrrolidone) as a stabilizer in the dispersion polymerization. The higher the content was of the crosslinking agent, the lower the swelling ratio was. Too much crosslinker gave unstable dispersions. Although the solvency of the precipitation polymerization mixture controlled the PNIPAAm microsphere size in the range of 0.2–1 μm, a micrometer range was obtained in the Shellvis 50 and Kraton G 1650 stabilized dispersion polymerizations of N‐isopropylacrylamide in toluene/heptane. Typically, the particles had fairly narrow size distributions. Copolymerization with the functional glycidyl methacrylate monomer afforded microspheres with reactive oxirane groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 968–982, 2006
Computational and experimental studies on the IR spectra and structure of the simplest nitriles (C1 and C2), their anions, and radicals
Authors: Georgieva Miglena K. , Velcheva Evelina A. 
Published: December 2005

AbstractThe structure and infrared spectra of formonitrile (hydrogen cyanide) and acetonitrile, their anions, and radicals (45 species in all) have been studied by density functional theory (DFT) B3LYP 6‐31++G(d,p) calculations. The results obtained have been compared with the literature and original experimental data. The zero‐point vibrational energy (ZPVE)‐corrected deprotonation energies of the studied (and other) nitriles correlate fairly well (R = 0.94) with their pKa values, measured in dimethyl sulfoxide (DMSO). The theoretical cyano stretching frequencies νCN of the species studied have been found to correlate satisfactorily (R = 0.97) with the experimental ones. The latter correlation can be used for a theoretical estimation of νCN of many nitriles, their anions, and radicals. The geometry parameters for the molecules, calculated by the same theoretical method, practically coincide with those determined experimentally in the gas state. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Beaklike SnO2 Nanorods with Strong Photoluminescent and Field‐Emission Properties
Authors: He Jr H. , Wu Te H. , Hsin Cheng L. , Li Kun M. , Chen Lih J. , Chueh Yu L. , Chou Li J. , Wang Zhong L. 
Published: December 2005

AbstractBeaklike SnO2 nanorods were synthesized by a vapor–liquid–solid approach using Au as a catalyst. The nanorods grow along the [10$\bar 1$] direction and the beak is formed by switching the growth direction to [1$\bar 1$$\bar 2$] through controlling the growth conditions at the end of the synthesis. The photoluminescence (PL) spectrum of the nanorods exhibits visible light emission with a peak at 602 nm. The field‐emission (FE) properties of the nanorods have been measured to exhibit a turn‐on field of 5.8 V μm−1. A comparative study of FE measurements between SnO2 nanorods with uniform diameters and these beaklike nanorods suggests that the shape and curved tips are important factors in determining the FE properties.
Near‐Edge X‐ray Absorption Fine Structure Spectroscopy as a Tool for Investigating Nanomaterials
Authors: Hemraj‐Benny Tirandai , Banerjee Sarbajit , Sambasivan Sharadha , Balasubramanian Mahalingam , Fischer Daniel A. , Eres Gyula , Puretzky Alexander A. , Geohegan David B. , Lowndes Douglas H. , Han Weiqiang , Misewich James A. , Wong Stanislaus S. 
Published: December 2005

AbstractWe have demonstrated near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy as a particularly useful and effective technique for simultaneously probing the surface chemistry, surface molecular orientation, degree of order, and electronic structure of carbon nanotubes and related nanomaterials. Specifically, we employ NEXAFS in the study of single‐walled carbon nanotube and multi‐walled carbon nanotube powders, films, and arrays, as well as of boron nitride nanotubes. We have focused on the advantages of NEXAFS as an exciting, complementary tool to conventional microscopy and spectroscopy for providing chemical and structural information about nanoscale samples.