bluuebunny/crossref_metadata_2025_split huggingface dataset:
Percutaneous tibial nerve stimulation in the treatment of overactive bladder: Urodynamic data
Authors: Vandoninck Vera , van Balken Michael R. , Finazzi Agrò Enrico , Petta Filomena , Micali Francesco , Heesakkers John P.F.A. , Debruyne Frans M.J. , Kiemeney Lambertus A.L.M. , Bemelmans Bart L.H. 
Published: April 2003

AbstractAimThe aim of this study was to evaluate urodynamic changes after percutaneous tibial nerve stimulation (PTNS) for the treatment of complaints related to overactive bladder syndrome and to search for urodynamic‐based predictive factors.MethodsNinety consecutive patients with symptoms related to overactive bladder syndrome were enrolled in this study. Patients underwent 12 PTNS sessions. For evaluating objective success, the primary outcome measure was a reduction in number of urinary leakage episodes of 50% or more per 24 hours. Patients' request for continuation of therapy was considered subjective success. This study focussed on urodynamic features at baseline and on changes found after 12 PTNS treatments.ResultsThe objective success rate was 56% (leakages/24 hours). Subjective success rate was 64%. Frequency/volume chart data and quality of life scores improved significantly (P < 0.01). Pre‐ and posturodynamic data were available from 46 participants. Detrusor instabilities (DI) could be abolished in a few cases only. Increments in cystometric bladder capacity and in volume at DI were significant (P = 0.043 and 0.012, respectively). Subjects without detrusor instabilities at baseline were 1.7 times more prone to respond to PTNS (odds ratio, 1.75; 95% confidence interval [CI], 0.67–4.6). The more the bladder overactivity was pronounced, the less these patients were found to respond to PTNS, the area under the receiver operating curve was 0.644 (95% CI, 0.48–0.804).ConclusionPTNS could not abolish DI. PTNS increased cystometric capacity and delayed the onset of DI. Cystometry seemed useful to select good candidates: patients without DI or with late DI onset proved to be the best candidates for PTNS. Neurourol. Urodynam. 22:227–232, 2003. © 2003 Wiley‐Liss, Inc.
Mechanism and process of chemomechanical contraction of polyelectrolyte gels under electric field
Authors: Kishi R. , Hasebe M. , Hara M. , Osada Y. 
Published: April 2003

AbstractWhen a water‐swollen polyelectrolyte gel is interposed between a pair of electrodes and DC current is applied, the gel undergoes electro‐chemomechanical contraction and concomitant water exudation both in water and in the air. In order to clarify the mechanism of the phenomenon, contractile experiments were carried out under various conditions and led to the conclusion that the contraction is essentially associated with electrically driven movement of hydrated micro‐ and macroions in the gel (electrokinetic process).
Evaluation of nonlinear optical susceptibility of polydiacetylenes by third harmonic generation
Authors: Nakanishi H. , Matsuda H. , Okada S. , Kato M. 
Published: April 2003

AbstractNonlinear optical susceptibility χ(3) of polydiacetylenes has been evaluated by third harmonic generation. First, in order to obtain the χ(3) tensor component along the polymer main chain, thin single crystals of two representative polydiacetylenes, poly‐PTS and poly‐DCHD were made by utilization of sampling technique in microscopy, i.e., the microtome cutting of single crystal embedded in plastic resin. The THG intensity observed was proportional to cos8θ, where θ was the angle between the polymer main chain and the polarization of laser light. The χ(3) value of poly‐DCHD was found to be rather higher than that of poly‐PTS. At resonant wavelength of 1.97 μm, the χ(3) of poly‐DCHD attained 8 x 10−10 esu. Furthermore, it was confirmed that when geometrical correction were properly made, the χ(3) obtained from polycrystalline thin film of poly‐PTS agreed well with that from thin single crystals. Secondary, regarding poly‐diphenyldiacetylene derivatives, it was found that the π‐conjugation between the polymer main chain and aromatic substituents was effective on the improvement of χ(3) values. The χ(3) magnitudes of poly‐BTFP and poly‐DFMP reflect well the dihedral angles between polymer main chain and the phenyl substituents (58° for poly‐BTFP and 67° for poly‐DFMP) as a measure of π‐conjugation. Especially, at nonresonant region of 2.1 μm the χ(3) of poly‐BTFP is about 5 times greater than that of poly‐PTS.
Studies of the structure of blends containing two liquid crystal polymers
Authors: DeMeuse Mark T. , Jaffe Michael 
Published: April 2003

AbstractBlends in which both of the component materials are capable of forming liquid crystalline phases are considered in the present work. Solid‐state characterization data are presented that suggest that chemical reaction is not a dominant event when two such materials are blended in the melt. Also, ideas of small‐molecule liquid crystal mixing are shown to be not applicable to describe the behavior of this system. A formalism for describing blends of liquid crystal polymers, based on Windle's sequence matching arguments, is proposed.
Electrooptical properties of liquid crystalline side chain polymers with laterally attached mesogenic units
Authors: Hirschmann H. , Jungbauer D. A. , Wolf M. , Wendorff J. H. , Finkelmann H. , Hessel F. 
Published: April 2003

AbstractThe electrooptical properties of side‐chain liquid crystalline polymers were investigated for the case that the mesogenic units were attached laterally rather than longitudinally to a flexible chain backbone via flexible spacer units. The experimental finding is that these polymers display unusual electrooptical properties within the isotropic phase in the neighborhood of the transition into the nematic phase.The polymers are characterized by the occurrence of a fast and a slow electrooptical response both of which show a critical divergence of the Kerr constant and the Kerr relaxation time. In addition, they show deviations between the rise and the decay values of the Kerr constants and in certain cases also of the Kerr relaxation times. Finally an overshoot of the induced birefringence following a sudden stepwise increase of the applied electric field has been found for one of these polymers. All these features can be accounted for on the basis of a newly developed theoretical approach that considers the particular dipolar and optical polarization configurations of these polymers.
Photocrosslinking of ultra high strength polyethylene fibers
Authors: Chen Yong Lie , Rånby Bengt 
Published: April 2003

AbstractUltra high strength polyethylene (HSPE) fibers have been successfully photocrosslinked using benzophenone as photoinitiator. The introduction of photoinitiator without disturbing the fiber structure is a difficult problem which was solved by vapor absorption at elevated temperature while keeping the fiber under constant strain. The crosslinked fiber showed no decrease in mechanical properties at room temperature as is the case when fibers are crosslinked by other reported methods such as radiation and chemical crosslinking. The crosslinked fiber showed enhanced high temperature resistance as well as much lower creep rate on prolonged stressing. Photocrosslinking of HSPE fiber is superior to other crosslinking methods reported in the literature.
New synthetic route of polyoxytetramethyleneglycol by use of heteropolyacids as catalyst
Authors: Aoshima Atsushi , Tonomura Shoichiro , Yamamatsu Setsuo 
Published: April 2003

AbstractPolyoxytetramethyleneglycol (PTMG) can be directly prepared from tetrahydrofuran (THF) and water in the presence of heteropolyacids (HPA), without the hydrolysis step. The reaction is carried out by mixing two liquid phases: the THF phase and a heteropolyacid catalyst phase. In this reaction the molar ratio of water to a heteropolyacid (H2O/HPA) in the catalyst phase plays an important role in the THF polymerization activity and the molecular weight of PTMG. IR spectrometric studies revealed that THF is coordinated to a heteropolyanion through either a water molecule or a proton in the catalyst phase. The latter type of coordination bings about the activation of THF capable of initiating the ring‐opening polymerization even in the presence of water at a lower acid strength. The PTMG prepared by this method has a narrow molecular weight distribution (M̄w/M̄n = 1.5 or less) and a number average molecular weight of 500–2000 which are requisite for the production of polyurethane elastomers. A new polymerization mechanism named “Phase Transfer Polymerization” is proposed for elucidating a narrow molecular weight distribution.
Reinforcement of amorphous thermoplastics by blending with a para‐linked aromatic LC‐polyester
Authors: Claßen M. S. , Schmidt H.‐W. , Wendorff J. H. 
Published: April 2003

AbstractThe preparation and the mechanical properties of binary blends of amorphous thermoplastics and a para‐linked liquid crystalline polyester, which is expected to act as a reinforcement, are reported. The LC‐polyester has the advantage that it is soluble in common organic solvents, that it has a low transition temperature, and that it does not crystallize readily. Polycarbonate, polystyrene, poly(methyl methacrylate), and poly(ether sulfone) were selected as matrix materials. Most of the films cast from the blends turned out to be turbid and thus phase separated, the sizes of the dispersed phases ranging between 0.2 μm (in polycarbonate) and 1 μm (in polystyrene).The LC‐polyester causes a substantial increase of the stiffness in blends with polycarbonate, poly(methyl methacrylate), and poly(ether sulfone) and almost no increase in the case of polystyrene. These differences are attributed to the particular magnitudes of the strength of the phase coupling between the matrix and the dispersed phase, which is controlled by their compatibility.
Features and origin of the dynamic and the nonlinear piezoelectricity in poly(vinylidene fluoride)
Authors: Harnischfeger P. , Jungnickel B.‐J. 
Published: April 2003

AbstractSome of the piezoelectric coefficients of poly(vinylidene fluoride) are distinctly stress dependent. We report on their dependence on the frequency of an oscillatory stress excitation, on the amount of the remanent polarization in the sample materials, and on the magnitude of an offset stress. In order to explain the observed dynamic and nonlinear piezoelectric properties, a model is developed that attributes them to changes in the local polarization in an interphase between the crystalline and amorphous phases in this semicrystalline polymer.
Poled amorphous polymers for second‐order nonlinear optics
Authors: Eich Manfred , Bjorklund Gary C. , Yoon Do Y. 
Published: April 2003

AbstractRecent advances in poled amorphous polymers for second‐order nonlinear optics are discussed with emphasis on stabilizing the frozen‐in nonlinearity via chemical crosslinking under electric fields. Specific examples of a linear polymer and a crosslinked polymer, both with nitroaniline‐type chromophores covalently attached as side groups, are presented and compared in their glass transition behavior, linear optical properties, poling dynamics, and stability of frozen‐in nonlinearity. It is demonstrated that by employing chemical crosslinking under electric fields one can prepare highly efficient and stable poled polymers that exhibit no decay in nonlinearity at ambient conditions and no apparent tendency of decay even at 85°C as well as excellent optical properties. The historical development of organic materials for second‐order nonlinear optics and recent advances in device fabrication based on poled polymers are also discussed briefly.
Curing and phase separation behavior of amine terminated butadiene acrylonitrile copolymer (ATBN) modified epoxy
Authors: Kim D. S. , Kim S. C. 
Published: April 2003

AbstractThe vitrification effect during the curing reaction of amine terminated butadiene acrylonitrile copolymer‐(ATBN)‐modified epoxy resin is studied by the differential scanning calorimetry. A new reaction kinetic equation is derived to describe the effect of vitrification on the reaction rate at both glassy and rubbery state of reactants. ATBN is added to improve the impact properties of the cured epoxy resin. The phase separation behavior during the curing reaction is analyzed by the light scattering and turbidity experiments. From the results of the cloud point measurements, it is observed that the ATBN‐epoxy system showed upper critical solution temperature (UCST) behavior. From the results of the light scattering experiments, the domain correlation length increases as the content of ATBN increases.
Gas transport in polyurethane–polystyrene interpenetrating polymer network membranes
Authors: Lee Doo Sung , Tak Tae‐Moon , Kim Geon Seok , Kim Sung Chul 
Published: April 2003

AbstractThe gas (oxygen and nitrogen) transport characteristics of the IPN membranes of polyurethane/polysturene were studied. The effect of synthesis temperature, composition, and crosslink density of the IPN membranes were analyzed. Polyurethane was prepared thermally and polystyrene was prepared by photolytic polymerization methods at various temperatures. The degree of intermixing between component polymers in the IPN membrane increased with decreasing synthesis temperature from 50°C to −10°C. The PS phase Tg was shifted inwardly up to 12°C. The permeability coefficient decreased and ideal separation factor increased also with decreasing the synthesis temperature due to the increase of miscibility. The permeability coefficient of oxygen and nitrogen ranged in the 10−10 and 10−10 order of magnitude. The permeability coefficient showed the minimum value and the ideal separation factor showed the maximum value at about 40 wt% polyrethane composition. The permeability data agreed well with the simple free volume model proposed by Lee [18].
Oxygen‐binding and transport in the liquid crystal membrane containing cobaltporphyrin as an oxygen carrier
Authors: Kawakami H. , Tsucla K. , Yamane K. , Nishide H. , Tsuchida E. 
Published: April 2003

AbstractComposite membrane is prepared from (N‐methoxybenzylidene)‐4‐butylaniline as a liquid crystalline phase, poly(methyl‐methacrylate) as a support, and α,α,α,α‐tetrakis(o‐pivalamidophenyl)‐porphinatocobalt(II) (CoP) as an oxygen carrier. Phase separation and transitions for the liquid crystal containing CoP in the composite membrane are confirmed by SEM and DSC. Kinetic and equilibrium constants of oxygen‐binding to CoP moiety fixed in the liquid crystal phase are spectroscopically determined in situ, and are discontinuously changed at the phase transition temperatures. Oxygen transport in the composite membrane is facilitated, because CoP moiety effectively acts as a fixed carrier for the oxygen transport.
Structure and properties of dynamically cured EPDM and ionomer blends
Authors: Ha C. S. , Cho W. J. , Hur Y. S. , Kim S. C. 
Published: April 2003

AbstractThe structure and properties of dynamically cured ethylene‐propylene‐diene terpolymer (EPDM) and ionomer blends have been studied. The blends were prepared in a laboratory internal mixer, where EPDM was cured under shear in the presence of ionomer with dicumyl peroxide (DCP) under different shear conditions. The effects of EPDM/ionomer compositions, DCP concentration and the intensity of shear mixing were investigated using capillary rheometer, differential scanning calorimeter (DSC) and scanning electron microscopy (SEM) techniques. Two kinds of poly(ethylene‐co‐methacrylic acid) ionomers containing different metal ions(Na+ and Zn++) were compared and the effect of the metal ion type for neutralization was considered. The Zn‐neutralized ionomer showed better miscibility with EPDM than the Na‐neutralized ionomer. It is concluded from the rheological properties, crystallization behavior and morphology that the dynamically cured EPDM and Zn‐ion ionomer blends show the behavior of a thermoplastic interpenetrating polymer network (IPN).
Fluorescence study of polyelectrolyte complex formation III: Mobility of probes in microdomains
Authors: Itoh Yoshihiro , Hachimori Akira , Abe Koji 
Published: April 2003

AbstractThe mobility of fluorescent probe molecules in the microdomains formed by polyelectrolyte complexes (PEC) in aqueous solution was investigated by the fluorescence polarization method. The degree of fluorescence polarization (p) for the anthracene (Anth) chromophores attached to anionic polyelectrolytes increased with complexation, indicating the restricted mobility of probe molecules in the PEC microdomains. These p values depended on the properties of added polycations, which were not in parallel with the fluorescence intensities of the Anth chromophores.
Study of the carbon fiber–poly(ether–ether–ketone) (PEEK) interfaces, 1: surface characterization of fibers and matrices, and interfacial adhesion energy
Authors: Nardin M. , Asloun E. M. , Schultz J. 
Published: April 2003

AbstractThe aim of this general study is to determine the physicochemical characteristics and mechanical properties of carbon fiber–PEEK interfaces.
In the first part, the dispersive component of the surface energy and the electron acceptor–donor (acid–base) characteristics of PEEK polymer and different types of untreated and surface‐treated carbon fibers are determined by means of inverse gas–solid chromatography at infinite dilution. It appears, in particular, that the acid–base surface properties of PEEK and, consequently, the orientation of macromolecules near the surface, depend on the processing of this polymer. Moreover, according to previous work, an estimation of the adhesion energy, corresponding to physical interactions (London and acid–base interactions) at carbon fiber–PEEK interfaces is proposed. Whatever the surface characteristics of PEEK, the highest level of carbon fiber–PEEK adhesion is achieved in systems involving oxidized or sized carbon fibers.
Study of the carbon fiber–poly(ether–ether–ketone) (PEEK) interfaces, 2: relationship between interfacial shear strength and adhesion energy
Authors: Nardin M. , Asloun E. M. , Schultz J. 
Published: April 2003

AbstractIn the second part of this general study, the carbon fiber–PEEK interfacial shear strength is measured by means of a fragmentation test on single‐fiber composites. Different thermal treatments (continuous cooling from the melt, isothermal treatments and long melting temperature time) are applied to these model composites prior to testing. The results are systematically compared with the previously determined reversible work of adhesion between carbon fiber and PEEK. It is shown that physical interactions at the interface determine, to a large extent, the magnitude of the interfacial shear strength between both materials. However, it appears that the magnitude of the stress transfer from the matrix to the fiber is affected either by the existence of an interfacial layer or by a preferential orientation of the polymer chains near the fiber surface. The results obtained on systems that have been subjected to isothermal treatments (isothermal crystallization of PEEK) seem to confirm the existence of a transcrystalline interphase, the properties of which are dependent upon the crystallization rate of the matrix and the interfacial adhesion energy.
Influence of sorbed carbon dioxide on transition temperatures of poly(p‐phenylene sulphide)
Authors: Schultze J. D. , Engelmann I. A. D. , Boehning M. , Springer J. 
Published: April 2003

AbstractStatic pressure usually increases the transition temperatures of polymers by decreasing their free volume. If the pressurizing medium is soluble in the polymer matrix, the opposing effect of increasing the free volume is possible. Those shifts of transition temperatures were monitored with a medium‐pressure Differential Scanning Calorimetry (DSC) device. The influences of sorbed and surrounding gas molecules are demonstrated by changes occurring in the transition temperature regions. The results show the severe plasticizing effect of CO2 on poly(p‐phenylene sulphide) (PPS). The glass transition temperature TG and the temperature of crystallization TC are influenced by sorbed gas molecules. They decrease due to sorbed CO2 molecules. Glass transition is lowered, but is difficult to interpret, as relaxation phenomena which diminish with increasing pressure occur during DSC runs. In crystallites no gas solution is usually possible, so that the melting point of PPS is mainly affected by influences other than plasticization.
Photoreactive Langmuir–Blodgett–Kuhn multilayer assemblies from functionalized liquid‐crystalline side chain polymers, I. Homopolymers containing azobenzene chromophores
Authors: Sawodny Michael , Schmidt Albert , Stamm Manfred , Knoll Wolfgang , Urban Claus , Ringsdorf Helmut 
Published: April 2003

AbstractStable monomolecular layers of a liquid‐crystalline homopolymer bearing azobenzene chromophores in the mesogenic side groups could be prepared at the water–air interface by slow compression at room temperature. From the area per monomer unit of A0≈0.25 nm2 a structural model with tightly packed azobenzene groups oriented nearly parallel to the surface normal was deduced. After transfer to a solid support in a Y‐type mode the obtained Langmuir–Blodgett–Kuhn (LBK) multilayer assemblies of varying thicknesses (from a double layer to a thick film of d = 238 nm, capable of guiding optical modes) were prepared and analyzed by X‐ray reflection and optical evanescent wave techniques. A monolayer thickness of d0 = 2.52 nm, as well as the anisotropic index of refraction of these layers, could thus be evaluated.Photo‐isomerization by UV‐irradiation (at λ = (360±30)nm) was examined by UV‐VIS absorption spectroscopy. X‐ray reflectivity data of samples illuminated for 30 min showed a complete loss of the layered structure of the LBK samples. As a result strongly light‐scattering films were obtained. Surface plasmon microscopy was used to demonstrate the usefulness of this photo‐induced order–disorder transition for optical information storage.
Investigation of phase morphology of incompatible polyethylene/nylon 6 blends containing EPDM‐based functionalized compatibilizers
Authors: Kim Jung Whan , Kim Sung Chul 
Published: April 2003

AbstractGraft copolymer and graft terpolymer were prepared by solution grafting of maleic anhydride (MAH) or acrylonitrile (AN) alone and mixture of MAH and AN on to ethylene–propylene–diene terpolymer (EPDM) using benzoyl peroxide (BPO) as an initiator. The resulting EPDM‐g‐MAH, EPDM‐g‐AN and EPDM‐g‐(MAH‐co‐AN) have been used to obtain a binary blend of Nylon 6/functionalized EPDM and a ternary blend of polyethylene/Nylon 6/functionalized EPDM by melt blending. The effects of the nature and the amount of the grafted species on the phase morphology, crystallization behavior and mechanical properties of the blends were characterized through scanning electron microscopy, optical microscopy, infrared spectroscopy and using a dynamic mechanical analyzer. From the morphological study, it can clearly be seen that the presence of the functionalized EPDMs in these blends resulted in an improvement of the dispersion degree in incompatible polyethylene/Nylon 6 blends.
Glass‐reinforced epoxy novolac composites
Authors: Patel R. D. , Patel M. B. , Patel R. G. , Patel V. S. 
Published: April 2003

AbstractEpoxy Phenolic novolac resins were prepared from the acid catalyzed condensation products of various phenols such as phenol, p‐cresol, p‐tert‐butyl‐phenol and cardanol with formaldehyde. All of these resins have been utilized to prepare the glass‐reinforced composites. The fabricated composites were evaluated for their mechanical and dielectric properties. The incorporation of an epoxy fortifier yielded a significant improvement in mechanical properties.