bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural properties of sodium ion implanted poly(vinyl alcohol) films
Authors: Bhat Narendra V. , Nate Mandar M. , Bambole Vaishali A. , Kurup M. B. 
Published: July 2005

AbstractPoly(vinyl alcohol) (PVA) films were implanted with sodium ions at various energies and total doses. Modified films were characterized by Fourier transform IR (FTIR), UV–visible (UV–vis), X‐ray diffraction (XRD), and scanning electron microscopy (SEM). From FTIR studies, it was evident that scission of the main chain occurred together with removal of hydrogen and hydroxyl groups. Sodium ions formed weak bonds with oxygen from the neighboring chains. UV–vis studies of implanted PVA showed increases in the absorbance values with the various energies and total doses. XRD studies revealed that, as the energy and total dose increased overall, the crystallinity decreased and new peaks at different 2θ values appeared. Changes in the crystallinity were also studied for thermally annealed PVA films in order to correlate and understand the phenomena of recrystallization due to ion implantation. The morphological features of the films were investigated by SEM. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 276–283, 2005
Physical, mechanical, and thermal properties of polyurethanes based on hydroxyalkylated cardanol–formaldehyde resins
Authors: Mythili C. V. , Malar Retna A. , Gopalakrishnan S. 
Published: July 2005

AbstractPolyurethanes are synthesized using three different hydroxyalkylated cardanol–formaldehyde resins, diphenylmethane diisocyanate (MDI), and a commercial polyol (PPG‐2000). These polyurethanes are found to be tough and crosslinked. A polyurethane prepared using a higher mole ratio of cardanol/formaldehyde of hydroxyalkylated cardanol–formaldehyde resin is found to possess better thermal and mechanical properties than the polyurethane prepared from a lower mole ratio. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 284–288, 2005
Studies on the poly(styrene‐b‐butadiene‐b‐styrene)/clay nanocomposites prepared by melt intercalation
Authors: Xu Hongde , Li Yang , Yu Dingsheng 
Published: July 2005

AbstractTwo types of SBS/OMMT composites are prepared by melt blending using a twin‐screw extruder. An X‐ray diffractometer indicates that polymer chains have intercalated into the gallery of the clay. It is shown in TEM photos that the thickness of the layer aggregate in the SBS1301 matrix is approximately 200 Å, but in the SBS4402 matrix the size of the filler particle is in micrometers. When SBS1301 is intermingled into SBS4402/OMMT, the particle size is reduced obviously. The tensile strength and elongation at break of the nanocomposite, SBS1301/OMMT, increase with the addition of OMMT; and when addition is 5phr, they achieve maximum. A small content of OMMT (less than 5phr) can prevent the deterioration of the mechanical properties of the SBS1301/MMT. In addition, a small content of SBS4402 (less than 20 wt %) can improve the mechanical properties of the SBS1301/OMMT composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 146–152, 2005
Theoretical and experimental analysis of interfacial instabilities in coextrusion flows
Authors: Zatloukal M. , Kopytko W. , Lengálová A. , Vlček J. 
Published: July 2005

AbstractInterfacial instabilities developed during two‐layer flows of LDPE melts were investigated theoretically through viscoelastic FEM analysis as well as experimentally on a flat multi‐manifold coextrusion die. During continuous reduction of the minor layer, the wave type appears in the film first whereas the zig‐zag type is only visible later, at the much thinner minor layer, which is an opposite order compared to film blowing coextrusion. Moreover, extensional viscosity of the minor layer was found to play a significant role from the interfacial instability point of view. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 153–162, 2005
Sorption/diffusion of aqueous mixtures of 1,4‐dioxane/tetrahydrofuran through blend membranes of poly(vinyl alcohol) and sodium alginate: Their compatibility and pervaporation separation studies
Authors: Kurkuri M. D. , Nayak J. N. , Aralaguppi M. I. , Naidu B. V. K. , Aminabhavi T. M. 
Published: July 2005

AbstractBlend membranes of poly(vinyl alcohol) (PVA) and sodium alginate (NaAlg) were prepared by solution casting and crosslinked with glutaraldehyde (GA). Polymer blend compatibility was studied in water by measuring solution viscosity at 30°C. From the viscosity data, interaction parameters were determined to find the blend compatibility. Thickness of the membranes ranged between 35 and 40 μm. Circular disc‐shaped samples were cut from the thin membranes to perform gravimetric sorption experiments in water + 1,4‐dioxane and water + tetrahydrofuran mixtures at 30°C. Diffusion coefficients were calculated using Fick's equation. Concentration profiles of liquids were computed by solving Fick's equation under suitable boundary conditions. Diffusion coefficients show a dependence on the composition of the blends as well as composition of binary mixtures. A correlation was attempted between concentration profiles and diffusion coefficients of the transporting liquids. Degree of swelling and sorption coefficients were calculated from the gravimetric sorption data. Sorption kinetics was studied using an empirical equation to understand the nature of sorption–diffusion anomalies. Membrane selectivity for water + 1,4‐dioxane and water + tetrahydrofuran mixtures were calculated from the pervaporation experiments. A correlation between sorption and membrane selectivity was attempted. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 178–188, 2005
Influence of the reaction conditions on the solid‐state graft copolymerization of methyl methacrylate and polyethylene/polypropylene in situ alloys
Authors: Fu Zhi‐Sheng , Xu Jun‐Ting , Jiang Guo‐Xin , Zhang Yan‐Zhong , Fan Zhi‐Qiang 
Published: July 2005

AbstractGraft copolymers of poly(methyl methacrylate) (PMMA) with spherical, high‐porosity polyethylene (PE)/polypropylene (PP) in situ alloys were synthesized by a solid‐state reaction. The effects of the amount of the free‐radical initiator, the feed ratio of the methyl methacrylate (MMA) monomer, the reaction temperature, and the composition of the alloys on the grafting degree of PMMA were studied. A greater amount of the initiator and a higher reaction temperature led to a higher grafting degree. The grafting degree first increased with the feed ratio of MMA but leveled off at a higher feed ratio. The obtained graft copolymer was fractionated by temperature gradient extraction fractionation into six fractions, and each fraction was characterized by Fourier transform infrared and differential scanning calorimetry. The structures of these fractions were ungrafted ethylene–propylene random copolymers and ethylene–propylene segmented copolymers, ethylene–propylene block copolymers having PE and PP segments of different lengths and grafted by PMMA, PP grafted by PMMA, and nearly pure PP. Most PMMA was grafted on propylene segments, and thus the grafting degree decreased as the content of ethylene units in the alloys increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 195–202, 2005
Effects of the oxidation temperature on the structure and properties of polyacrylonitrile‐based activated carbon hollow fiber
Authors: Sun Junfen , Wang Qingrui 
Published: July 2005

AbstractPolyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate, oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of the oxidation temperature of the PAN hollow fiber precursor on the microstructure, specific surface, pore size distribution, and adsorption properties of PAN‐based activated carbon hollow fiber (PAN‐ACHF) were studied. When PAN hollow fibers were oxidized at 270°C, because of drastic oxidation, chain scission occurred, and the number of pores within and on the surface of the resultant PAN‐ACHF increased, but the pores were just in the thinner region of the skin of PAN‐ACHF. The surface area of PAN‐ACHF reached a maximum when the oxidation temperature was 270°C. The adsorption ratios to creatinine were all higher than 90% at all oxidation temperatures, and the adsorption ratio to VB12 reached a maximum (97%) at 230°C. The dominant pore sizes of the mesopores in PAN‐ACHF ranged from 2 to 5 nm. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 203–207, 2005
Synthesis and characterization of low‐molecular‐weight hydrogenated polybutadiene‐b‐poly(ethylene glycol) block copolymers
Authors: Xu Jun‐Ting , Jin Wei , Fan Zhi‐Qiang 
Published: July 2005

AbstractLow‐molecular‐weight hydrogenated polybutadiene‐b‐poly(ethylene glycol) (HPBd‐b‐PEG) block copolymers with double crystallizable blocks were synthesized by the coupling of hydroxyl‐end‐group‐containing hydrogenated polybutadiene and poly(ethylene glycol) with terephthaloyl chloride as a coupling reagent. The block structure was confirmed by 1H‐NMR, and the molecular weights of the blocks were determined as well. Gel permeation chromatography showed that the HPBd‐b‐PEG block copolymers had narrow molecular weight distributions. The crystallization and superstructures of the HPBd‐b‐PEG block copolymers were studied with differential scanning calorimetry, wide‐angle X‐ray diffraction (WAXD), and polarized optical microscopy. The results revealed that the crystallization of both blocks was suppressed mutually, especially for the shorter block. WAXD patterns showed that the crystal structures remained unchanged for both blocks. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 208–215, 2005
Preparation and characterization of linear low‐density polyethylene/low‐density polyethylene/TiO2 membranes
Authors: Wang Xuyun , Wang Zhaobo , Wang Xin 
Published: July 2005

AbstractBecause of their special functions, the application of nanoscale powders has recently attracted both industrial and theoretical interest. In this study, nanoscale TiO2, which exhibited a special UV absorption and consequent antibacterial function, was added to a low‐density polyethylene/linear low‐density polyethylene hybrid by melt compounding to yield functional composite membranes. TiO2 exhibited an apparent induced nucleation effect on the crystallization of polyethylene, and the size of the crystallites decreased while the number increaed with the introduction of TiO2; however, the crystallinity of polyethylene changed little. Also, TiO2 exhibited an ideal dispersion in the membrane with an average size less than 100 nm, and this excellent dispersion provided the membranes extra UV absorption; moreover, the transparency of the membranes was maintained to satisfy common requirements. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 216–221, 2005
New method for preparing polybutadiene rubber/clay composites
Authors: Wang Shaohui , Zhang Yong , Peng Zonglin , Zhang Yinxi 
Published: July 2005

AbstractPolybutadiene rubber (BR)/clay/dimethyl dihydrogenatetallow ammonium chloride (DDAC) composites were prepared by a new preparation method named in situ organic modification. That is, BR, pristine clay, and quaternary ammonium salt were directly melt‐mixed without the usual pretreatment of the pristine clay with an intercalatant. BR/pristine clay, BR/organoclay DK4 (modified with DDAC), and BR/clay/DDAC composites were analyzed with X‐ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The vulcanization characteristics and mechanical properties of the BR/pristine clay, BR/DK4, and BR/clay/DDAC composites were investigated. Finally, the effects of the processing conditions, clay/DDAC ratio, and clay content on the structure and properties of the BR/clay/DDAC composites were investigated. The results showed that intercalated BR/clay/DDAC composites were prepared. Organoclay DK4 and clay/DDAC effectively accelerated the vulcanization reaction of BR, which was attributed to the existence of the intercalatant used to modify the clay. The tensile strength, elongation at break, and tear strength of the BR/clay/DDAC vulcanizates were greatly improved in comparison with those of gum BR and BR/pristine clay vulcanizates but were somewhat lower than those of BR/DK4 vulcanizates. The dispersion of clay particles in the BR/clay/DDAC and BR/DK4 composites was much better than that in the BR/pristine clay composite. The temperature at the thermal degradation peak of the BR/clay/DDAC composite obviously increased in comparison with those of the gum BR, BR/clay and BR/DK4 composites. The mixing temperature and rotor speed had remarkable effects on the structure and properties of the BR/clay/DDAC composite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 227–237, 2005
Composition distributions of different particles of a polypropylene/poly(ethylene‐co‐propylene) in situ alloy analyzed by temperature‐rising elution fractionation
Authors: Xu Jun‐Ting , Jin Wei , Fu Zhi‐Sheng , Fan Zhi‐Qiang 
Published: July 2005

AbstractFragmentation was observed in the polymerization process for the preparation of a polypropylene (PP)/poly(ethylene‐co‐propylene) (EPR) in situ alloy. Composition distributions of different polymer particles were analyzed by preparative temperature‐rising elution fractionation. The fractions eluted at room temperature and 96, 110, and 117°C were selected for 13C‐NMR characterization. There was more propylene homopolymer and ethylene–propylene block copolymer in the large particles, whereas the small particles contained more ethylene–propylene random copolymer and copolymer with a transition microstructure. On the basis of the formation mechanism of various components in the PP/EPR alloy, we inferred that the fragmentation of the polymer particles mainly took place in the copolymerization step. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 243–246, 2005
Parsing the public domain
Authors: Maxwell Terrence A. 
Published: July 2005

AbstractThis article explores the use of the term public domain in the American context and finds that the symbol is subject to multiple meanings. Using historical and content analysis, the analysis explores the various uses of the term and provides a preliminary taxonomy for subsequent analysis and theory building. In conclusion, it suggests that more coherent information policies regarding national and international information access, creativity, governance, and private property rights will require a better understanding and delineation of the use of public domain in legislative and common practice.
Structural properties of polyC–scleroglucan complexes
Authors: Sletmoen Marit , Stokke Bjørn T. 
Published: July 2005

AbstractSuccessive changes of solvent conditions can be used to dissociate and reassociate the triple‐helical structure of (1,3)‐β‐D‐glucans. Ultramicroscopic techniques have revealed a blend of circular and other structures following renaturation. When this solvent exchange process is carried out in the presence of certain polynucleotides, the process creates a novel macromolecular complex. Here, we use size exclusion chromatography (SEC) to study such (1,3)‐β‐D‐glucan‐polynucleotide complexes. Online multiangle laser‐light scattering (MALLS) and refractive index (RI) detectors allowed determination of molecular weight and radius of gyration of the molecules. An ultraviolet (UV) detector allowed specific detection of the polynucleotide. The poly‐cytidylic acid (polyC) shifted to coelution with the linear fraction of the scleroglucan following the renaturation of polyC–scleroglucan blends, indicating that polyC is incorporated in linear, but not in circular, structures of scleroglucan. This conclusion was consistent with AFM topographs that revealed a decreased fraction of circular structures upon addition of polyC during the renaturation process. The combined information about radius of gyration (Rg) and molecular weight (Mw) allowed us to conclude that the polyC–scleroglucan complexes are more dense and have a higher persistence length than linear scleroglucan triple helixes. The experimentally determined mass per unit length was used as a basis for elucidating possible molecular arrangements within the polyC–scleroglucan complex. © 2005 Wiley Periodicals, Inc. Biopolymers 79: 115–127, 2005This 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
Highly Productive Autocondensation and Transglycosylation Reactions with Sulfolobus solfataricus Glycosynthase
Authors: Trincone Antonio , Giordano Assunta , Perugino Giuseppe , Rossi Mosè , Moracci Marco 
Published: July 2005

AbstractTransglycosylation reactions (autocondensation of the substrate or transfer of the glycon donor moiety to different acceptors) with the hyperthermophilic glycosynthase from Sulfolobus solfataricus acting in dilute sodium formate buffer at pH 4.0 are reported; the use of 4‐nitrophenyl β‐glucopyranoside as both donor and acceptor in the self‐transfer reaction and a highly productive reaction with 1.1 M 2‐nitrophenyl β‐glucopyranoside were possible. Interesting effects, governed by the anomeric configuration and lipophilicity of heteroacceptors, on the regioselectivity and yield of reactions were found for the first time with this enzyme and are discussed. The results demonstrate the unexplored synthetic potential of this glycosynthase; the tuning of the reaction conditions and the choice of different donors/acceptors can lead to products of applicative interest.
Multiparameter Imaging for the Analysis of Intracellular Signaling
Authors: Schultz Carsten , Schleifenbaum Andreas , Goedhart Joachim , Gadella Theodorus W. J. 
Published: July 2005

AbstractIn biological experimentation and especially in drug discovery there is a trend towards more complex test systems. Cell‐based assays are replacing conventional binding or enzyme assays more and more. This development is strongly driven by novel fluorescent probes that give insight into cellular processes. Target proteins are studied in their natural environment; this gives much more realistic test results, especially with respect to enzyme location and kinetics. However, in the complex environment of cells, many parameters contribute to the performance of the protein of interest. Therefore, it would be desirable to monitor simultaneously as many of the relevant cellular processes as possible. Here, we discuss the possibilities and limitations provided by multiparameter monitoring of cellular events with fluorescent probes. Some novel examples of the use of fluorescent probes and multiparameter imaging are shown.
Mechanism‐Based Fluorescent Reporter for Protein Kinase A Detection
Authors: Law Benedict , Weissleder Ralph , Tung Ching‐Hsuan 
Published: July 2005

AbstractA novel mechanism‐based fluorescent reporter was designed for the detection of protein kinase A (PKA), which is known to mediate a variety of cellular responses in most eukaryotic cells. The probe consists of a specific binding peptide sequence, LRRRRFAFC, conjugated with 2′‐thioethyl‐5‐(or ‐6)‐carboxyfluoresceinamide (FAMS; 2) and 5‐(or 6‐)carboxytetramethylrhodamine (TAMRA) at the cysteine and leucine residues, respectively. In the absence of PKA, the two fluorophores associate by hydrophobic interactions, forming an intramolecular ground‐state dimer; this results in fluorescein quenching (>93 %). Upon PKA addition, the reporter reacts with the sulfhydryl functionality at Cys199 through a disulfide‐exchange mechanism. FAMS is subsequently released, resulting in significant fluorescence amplification. The remaining peptide sequence, which acts as an inhibitor, is attached covalently to the enzyme. Our results suggest that this type of sensors could have far‐reaching applications in the molecular sensing of enzymes.
Surface‐Grafted Multiporphyrin Arrays as Light‐Harvesting Antennae to Amplify Photocurrent Generation
Authors: Morisue Mitsuhiko , Yamatsu Shigeru , Haruta Noriko , Kobuke Yoshiaki 
Published: July 2005

AbstractOrganized multiporphyrin arrays were developed on the conductive surface by a novel coordination‐directed molecular architecture aiming at efficient photoelectric conversion. The basic strategy employs the mutual coordination of two imidazolylporphyrinatozinc(II) units to form a cofacial dimer. Thus, meso,meso‐linked bis(imidazolylporphyrinatozinc) (Zn2(ImP)2) was organized onto imidazolylporphyrinatozinc on the gold substrate as a self‐assembled monolayer. The organized Zn2(ImP)2 bearing allyl side chains was covalently linked by ring‐closing olefin metathesis catalyzed with Grubbs catalyst. Alternating coordination/metathesis reactions allow the stepwise accumulation of multiporphyrin arrays on the gold electrode. A successive increase in absorption over a wide wavelength range occurred after each accumulation step of Zn2(ImP)2 on the gold electrode, and cathodic photocurrent generation was enhanced in the aqueous electrolyte system, containing viologen as an electron carrier. The significant increase of the photocurrent indicates that the multiporphyrin array works as a “light‐harvesting antenna” on the gold electrode.
A Multinuclear NMR Relaxometry Study of Ternary Adducts Formed between Heptadentate GdIII Chelates and L‐Lactate
Authors: Terreno Enzo , Botta Mauro , Boniforte Patrizia , Bracco Chiara , Milone Luciano , Mondino Bruna , Uggeri Fulvio , Aime Silvio 
Published: July 2005

AbstractDramatic relaxation enhancements of L‐lactate resonances have been observed upon formation of ternary adducts with GdIII complexes of heptadentate DO3A and DO3A‐like ligands (DO3A=1,4,7,10‐tetraazaciclododecane‐1,4,7‐triacetic acid). Detailed 1H and 17O NMR relaxometry investigations allow us to obtain structural, dynamic and thermodynamic information on the ternary complexes in which L‐lactate acts as a bidentate ligand replacing two water molecules in the inner coordination sphere of the GdIII ion. It has been found that the exchange rate of the coordinated L‐lactate is modulated by the structural and electronic properties of the parent Gd‐heptacoordinated macrocyclic chelate. In addition to the characterisation of the relaxation behaviour of the 1H methyl resonance of L‐lactate, this study has been extended to its 13C isomer (fully enriched at the three positions) and to the trifluoro‐L‐lactate. The obtained results may be relevant to the development of relaxation agents able to promote the relaxation enhancement of specific substrates detectable by in vivo magnetic resonance spectroscopy.