bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheological behavior of brominated isobutylene‐co‐paramethylstyrene: Effect of fillers, oil and blending with EPDM
Authors: Kumar Bhuwneesh , De S. K. , Bhowmick A. K. , De P. P. , Peiffer D. G. 
Published: April 2004

AbstractThe melt flow properties of unfilled and filled brominated isobutylene‐co‐paramethylstyrene (BIMS) were measured by means of a capillary viscometer at three different temperatures (90°C, 110°C and 130°C) and four different shear rates (61, 122, 245 and 306 s−1). The effect of addition of EPDM rubber on melt flow properties of unfilled BIMS was also studied. Evaluation of the processability was done by measuring the extrudate roughness (ER) of the extrudates obtained from the MPT. The viscosity of the systems decreased with the shear rate, indicating their pseudoplastic or shear thinning nature. As expected, the viscosity of BIMS increased with the addition of fillers and decreased with the addition of oil. For the neat systems, viscosity increased with the addition of EPDM, and the blends showed a positive deviation, indicating interdiffusion of the polymer chains across the phase boundaries. The activation energy of the filled systems at constant filler loading increased with increasing filler surface area (N330 > N550 > N774, each at 30 phr loading), and filler loading (50 > 30 > 10 phr, for N330) and decreased with the addition of oil (2.5 > 5.0 > 7.5 phr, for system containing 30 phr of N330). The silica filled system showed a higher activation energy and ER than the carbon black‐filled systems. With addition of N330 and N550 carbon blacks to BIMS, the extrudate roughness (ER) decreased, whereas it increased with the addition of N774 carbon black. With an increase in filler loading, ER initially increased and then decreased as compared to the neat system. For the filled systems, ER initially decreased up to 5 phr of oil, beyond which it increased.
Effects of molecular weight and clay organo‐ions on the melt intercalation of poly(ethylene oxide) into layered silicates
Authors: Shen Zhiqi , Simon George P. , Cheng Yi‐Bing 
Published: April 2004

AbstractA useful and desirable method of synthesizing nanoscale organic‐inorganic composites is to intercalate polymers into layered silicates by melt intercalation. Nanocomposites of poly(ethylene oxide) with a sodium montmorillonite and an organoions exchanged bentonite have been prepared by melt intercalation. The effects of polymer molecular weight, the nature of the clay (one unmodified, the other with organo‐ion) and the presence of water molecules in the clay galleries have been investigated. Based on X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), a distorted helical conformation is thought to describe the conformation of the PEO chains in the hybrid materials.
Characterization of monopolymer blend of virgin and recycled polyamide 6
Authors: Scaffaro R. , La Mantia F. P. 
Published: April 2004

AbstractIt is a common industrial practice to blend virgin polymer with the same recycled polymer coming from plastic scraps that, in general, has not undergone relevant degradation. In this work, the characteristics of blends of virgin and recycled polyamide have been considered by changing the amount of recycled polymer and the presence of humidity and a stabilizer. Neither dry nor wet stabilized recycled polyamide samples show significant variations of the molecular weight, but the melt Newtonian viscosity of the blends are slightly different from that predicted by an additive rule, despite the same chemical nature of the two components. This holds true even more for the humid unstabilized sample, as its noticeably lower molecular weight implies values lower than those expected on a linearity basis. The situation is different for the mechanical properties; here the morphology reached in the solid state determines a more rigid and brittle material, compared to the pure components, with relevant deviations from linearity for all the recycled samples used to prepare the blends. A different crystallinity as a function of the composition can be invoked to explain this phenomenon. The blends containing dry and wet stabilized recycled polyamide show almost the same behavior, confirming the reduced degradation of these samples.
A novel pH‐sensitive gelatin–DNA semi‐interpenetrating polymer network hydrogel
Authors: Liu Wen Guang , Li Xiao Wei , Ye Gui Xiang , Sun Shu Jun , Zhu Dunwan , Yao Kang De 
Published: April 2004

AbstractGelatin and DNA were mixed together in various ratios followed by the addition of glutaraldehyde as a cross‐linker. FT‐IR spectroscopy confirmed the formation of a semi‐interpenetrating polymer network (semi‐IPN) between the gelatin and DNA. The gelatin–DNA semi‐IPN hydrogel underwent, reversibly, remarkable changes in swelling degree in response to the variation of pH. In the low‐pH range, the hydrogel showed a lower swelling degree; with an increment in pH, the hydrogel was highly swollen, which is considered to originate from the complexation and de‐complexation between gelatin and DNA, as was verified by turbidity measurements. Higher contents of DNA result in an increase in the swelling degree, which is presumably due to the easy outward expansion of free DNA moieties. The permeability coefficient, P, for a model molecule, cimetidine, through the semi‐IPN hydrogel membranes was determined in pH 1.0 and pH 12.0 buffer solutions. The results show that the permeation of cimetidine is responsive to pH change, and an evident variation in the P values occurs in response to the pH of the media. Copyright © 2004 Society of Chemical Industry
Electroless recovery of gold chloride using inherently conducting polymers
Authors: Ding Jie , Price William E , Ralph Stephen F , Wallace Gordon G 
Published: April 2004

AbstractConducting polymers deposited onto reticulated vitreous carbon (RVC) were shown to remove gold from aqueous solutions in a facile and highly efficient fashion. For acidic solutions with initial [AuCl4]− concentrations between 0.1 and 1000 ppm, gold recoveries >90% were obtained. Experiments, conducted using solutions containing 0.1 ppm [AuCl4]−, also demonstrated that the composite materials were significantly more effective at recovering gold than activated carbon. Gold removal from solutions containing [AuCl4]− and much higher concentrations of iron was highly selective. Copyright © 2004 Society of Chemical Industry
Two‐dimensional maps and databases of the human macrophage proteome and secretome
Authors: Dupont Annabelle , Tokarski Caroline , Dekeyzer Olivia , Guihot Anne‐Laure , Amouyel Philippe , Rolando Christian , Pinet Florence 
Published: April 2004

AbstractMacrophages exert a crucial, but still incompletely known, role in complex disorders such inflammatory, immunological, and infectious diseases. A differential proteomic approach should help to elucidate the macrophage dysfunctions involved in these diseases. With this goal in mind, we established the first two‐dimensional maps of the human macrophage proteome and secretome. Intracellular and secreted proteins were extracted from monocyte‐derived macrophages obtained from healthy donors (n = 16), and separated by two‐dimensional gel electrophoresis. Silver‐stained gels were analyzed using Progenesis software. A high level of between‐gel reproducibility was obtained, allowing us to generate two patterns specific of the macrophage proteome and secretome, respectively. A total of 127 and 66 distinct intracellular and secreted polypeptide spots, corresponding to 100 and 38 different proteins, respectively, were identified by matrix assisted laser desorption/ionisation‐mass spectrometry. The two‐dimensional reference maps and databases resulting from this study confirm that macrophages are involved in a wide range of biological functions, and that they provide a useful tool for a wide array of investigators involved in macrophage biology, allowing to investigate the macrophage protein changes associated with various disorders or environmental stimuli.
Dispensable role for interferon‐γ in the burn‐induced acute phase response: A proteomic analysis
Authors: Duan Xunbao , Yarmush David M. , Jayaraman Arul , Yarmush Martin L. 
Published: April 2004

AbstractWe examined the role of the pleiotropic cytokine interferon‐γ (IFN‐γ) in initiating the burn injury‐induced acute phase response (APR). Two‐dimensional (2‐D) electrophoresis was used to obtain serum protein profiles from wild‐type (WT) and IFN‐γ knockout mice following sham‐burn or 20% burn injury. Serum 2‐D images from both groups of burn‐injured mice were characterized by the upregulation of a similar panel of protein spots. These included the three major murine acute phase proteins haptoglobin, serum amyloid A, and serum amyloid P, that were identified by matrix‐assisted laser desorption/ionization‐time of flight (MALDI‐TOF)‐mass spectrometry. Furthermore, the changes in the levels of these protein spots were very similar between these two groups of mice, as determined by image analysis. Other features of burn‐induced APR such as a decrease in total serum protein concentration, an elevated circulation level of the cytokine interleukin‐6 (IL‐6), and activation of the IL‐6 signal transduction protein STAT3 were also evaluated and found to be similar between wild‐type and IFN‐γ knockout mice. These results suggest a dispensable role of IFN‐γ in the induction of the hepatic APR in mice following burn injury.
The RESID Database of Protein Modifications as a resource and annotation tool
Authors: Garavelli John S. 
Published: April 2004

AbstractThe RESID Database of Protein Modifications is a comprehensive collection of annotations and structures for protein modifications and cross‐links including pre‐, co‐, and post‐translational modifications. The database provides: systematic and alternate names, atomic formulas and masses, enzymatic activities that generate the modifications, keywords, literature citations, Gene Ontology (GO) cross‐references, protein sequence database feature table annotations, structure diagrams, and molecular models. This database is freely accessible on the Internet through resources provided by the European Bioinformatics Institute (http://www.ebi.ac.uk/RESID), and by the National Cancer Institute – Frederick Advanced Biomedical Computing Center (http://www.ncifcrf.gov/RESID). Each RESID Database entry presents a chemically unique modification and shows how that modification is currently annotated in the protein sequence databases, Swiss‐Prot and the Protein Information Resource (PIR). The RESID Database provides a table of corresponding equivalent feature annotations that is used in the UniProt project, an international effort to combine the resources of the Swiss‐Prot, TrEMBL and PIR. As an annotation tool, the RESID Database is used in standardizing and enhancing modification descriptions in the feature tables of Swiss‐Prot entries. As an Internet resource, the RESID Database assists researchers in high‐throughput proteomics to search monoisotopic masses and mass differences and identify known and predicted protein modifications.
Preparation and properties of new polyimides and polyamides based on 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene
Authors: Hsiao Sheng‐Huei , Yang Chin‐Ping , Huang Sheng‐Ching 
Published: April 2004

AbstractA novel, trifluoromethyl‐substituted, bis(ether amine) monomer, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene, was synthesized through the nucleophilic displacement of 2‐chloro‐5‐nitrobenzotrifluoride with 1,4‐dihydroxynaphthalene in the presence of potassium carbonate in dimethyl sulfoxide, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new fluorine‐containing polyimides with inherent viscosities of 0.57–0.91 dL/g were prepared by reacting the diamine with six commercially available aromatic dianhydrides via a conventional, two‐step thermal or chemical imidization method. Most of the resulting polyimides were soluble in strong polar solvents such as N‐methylpyrrolidone and N,N‐dimethylacetamide (DMAc). All the polyimides afforded transparent, flexible, and strong films with good tensile properties. These polyimides exhibited glass‐transition temperatures (Tg's) (by DSC) and softening temperatures (by thermomechanical analysis) in the ranges of 252–315 and 254–301 °C, respectively. Decomposition temperatures for 5% weight loss all occurred above 500 °C in both air and nitrogen atmospheres. The dielectric constants of these polyimides ranged from 3.03 to 3.71 at 1 MHz. In addition, a series of new, fluorinated polyamides with inherent viscosities of 0.32–0.62 dL/g were prepared by the direct polycondensation reaction the diamine with various aromatic dicarboxylic acids by means of triphenyl phosphite and pyridine. All the polyamides were soluble in polar solvents such as DMAc and could be solution‐cast into tough and flexible films. These polyamides had Tg's between 228 and 256 °C and 10% weight‐loss temperatures above 400 °C in nitrogen or air. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2377–2394, 2004
Melt‐processable thermosetting polyimide: Synthesis, characterization, fusibility, and property
Authors: Kuroki T. , Shibuya A. , Toriida M. , Tamai S. 
Published: April 2004

AbstractTo obtain a melt‐processable thermosetting polyimide having a high glass‐transition temperature (Tg) and good solvent resistance, the effect of introducing a crosslinkable agent into the polymer chain ends of the melt‐processable polyimide on its physical properties was studied. The polyimide (calculated number‐average molecular weight (Mn) = 11,600 g/mol) capped with the crosslinkable agent exhibited poor melt flowability because its crosslinkable agent reacted at the processing temperature of 360 °C. To reduce the rate of crosslink reaction, two methods were investigated. One was lowering the processing temperature, and the other was decreasing the amount of crosslinkable agent. The low‐molecular‐weight oligomer (calculated Mn = 6300 g/mol) capped with the crosslinkable agent exhibited good melt flowability at the lower processing temperature of 340 °C where the crosslinkable agent did not react. However, the obtained molded part of this oligomer was too brittle to maintain its shape. However, the polyimide (calculated Mn = 11,600 g/mol) partially capped with the crosslinkable agent demonstrated good melt flowability at the processing temperature of 360 °C. Furthermore, the molded part of this resin was strong and tough. In addition, the cured part exhibited high Tg and good solvent resistance. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2395–2404, 2004
Synthesis of hydrophilic/CO2‐philic poly(ethylene oxide)‐b‐poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate) block copolymers via controlled/living radical polymerizations and their properties in liquid and supercritical CO2
Authors: Ma Zhi , Lacroix‐Desmazes Patrick 
Published: April 2004

AbstractHydrophilic/CO2‐philic poly(ethylene oxide)‐b‐poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate) block copolymers were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization, iodine transfer polymerization (ITP), and atom transfer radical polymerization (ATRP) in the presence of either degenerative transfer agents or a macroinitiator based on poly(ethylene oxide). In this work, both RAFT and ATRP showed higher efficiency than ITP for the preparation of the expected copolymers. More detailed research was carried out on RAFT, and the living character of the polymerization was confirmed by an ultraviolet (UV) analysis of the SC(S)Ph or SC(S)SC12H25 end groups in the polymer chains. The quantitative UV analysis of the copolymers indicated a number‐average molecular weight in good agreement with the value determined by 1H NMR analysis. The properties of the macromolecular surfactants were investigated through the determination of the cloud points in neat liquid and supercritical CO2 and through the formation of water‐in‐CO2 emulsions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2405–2415, 2004
Self‐bonding in an amorphous polymer below the glass transition: A T‐peel test investigation
Authors: Boiko Yuri M. , Bach Anders , Lyngaae‐Jørgensen Jørgen 
Published: April 2004

AbstractFilms of amorphous polystyrene (PS) with a weight‐average molecular weight (Mw) of 225 × 103 g/mol were bonded in a T‐peel test geometry, and the fracture energy (G) of a PS/PS interface was measured at the ambient temperature as a function of the healing time (th) and healing temperature (Th). G was found to develop with (th)1/2 at Th = Tg‐bulk − 33 °C (where Tg‐bulk is the glass‐transition temperature of the bulk sample), and log G was found to develop with 1/Th at Tg‐bulk − 43 °C ≤ Th ≤ Tg‐bulk − 23 °C. The smallest measured value of G = 1.4 J/m2 was at least one order of magnitude larger than the work of adhesion required to reversibly separate the PS surfaces. These three observations indicated that the development of G at the PS/PS interface in the temperature range investigated (<Tg‐bulk) was controlled by the diffusion of chain segments feasible above the glass‐transition temperature of the interfacial layer, in agreement with our previous findings for fracture stress development at several polymer/polymer interfaces well below Tg‐bulk. Close values of G = 8–9 J/m2 were measured for the symmetric interfaces of polydisperse PS [Mw = 225 × 103, weight‐average molecular weight/number‐average molecular weight (Mw/Mn) = 3] and monodisperse PS (Mw = 200 × 103, Mw/Mn = 1.04) after healing at Th = Tg‐bulk − 33 °C for 24 h. This implies that the self‐bonding of high‐molecular‐weight PS at such relatively low temperatures is not governed by polydispersity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1861–1867, 2004
Analysis of electronic delocalization in buckminsterfullerene (C60)
Authors: Poater J. , Duran M. , Solà M. 
Published: April 2004

AbstractBuckminsterfullerene (C60) presents an extensive conjugation that, in principle, should lead to a high delocalization of its electrons, together with a notorious aromaticity. However, previous studies have shown that C60behaves chemically and physically as an electron‐deficient alkene rather than an electron‐rich aromatic system. In the current work, we try to better elucidate the extension of electron delocalization in C60by computing the delocalization index for a given carbon atom of C60. We show that, in C60, local electron delocalization per carbon atom is lower than that in benzene and naphthalene. However, C60presents a global electron delocalization per carbon atom that is almost the same as that of clearly aromatic systems such as benzene or naphthalene. This is attributed to the fact that the electron charge of each atom in C60can be shared with a larger number of atoms. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Geometry optimization and transition state search in enzymes: Different options in the microiterative method
Authors: Prat‐Resina Xavier , Bofill Josep Maria , González‐Lafont Àngels , Lluch José M. 
Published: April 2004

AbstractIn the current article we present a systematic analysis of the different options in the so‐called “microiterative method” used to locate minima and transition‐state (TS) structures of big systems on quantum mechanics/molecular mechanics potential energy surfaces. The method splits the system in two parts: a core zone in which accurate second‐order search is carried out, and an environment that is kept minimized with a cheap first‐order algorithm. The different options studied here are: the alternating frequency between the environment minimization and the TS search in the core, the number of atoms included in each zone, and two alternative ways to reduce the computational cost in the calculation of core–environment interactions. The tests have been done at two different steps of the enzymatic mechanism of mandelate racemase: a proton transfer and a carbon configuration inversion step. The two selected TS structures differ in the number of atoms involved in their associated transition vectors; the proton transfer TS is an example of a local motion, whereas the carbon configuration inversion TS corresponds to a more global movement of several groups and residues, including an important number of atoms. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
The first solvation shell of aluminum (III) and magnesium (II) cations in a protein model environment
Authors: Mercero Jose M. , Matxain Jon M. , Rezabal Elixabete , Lopez Xabier , Ugalde Jesus M. 
Published: April 2004

AbstractAluminum (III) cation interactions with relevant bioligands have been studied in a protein‐model environment (in the gas and aqueous phases) using density functional theory methods. The protein model consists of the metal cation bound to a chosen bioligand and water molecules interacting with the cation to complete its first coordination shell. The ligands are the functional groups of the amino acid side chains. Binding energies and formation energies are calculated in both phases. Analogous magnesium (II) complexes are also calculated, and the possibility of magnesium/ aluminum exchange is estimated. The effect of the dielectric media is also discussed. This aims to model different regions inside a protein (solvent accessible and buried regions). It is found that the effect of the dielectric is very important, for example, for the negatively charged ligand complexes, magnesium/aluminum exchange is possible only in low dielectric environments such as partially buried protein regions. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
VisionMark: A media linking method creating synergy of information transmission media and the Internet
Authors: Miyaoku Kento , Shigeyoshi Hiroki , Akutsu Akihito , Tonomura Yoshinobu 
Published: April 2004

Abstract“VisionMark” is a media linking method for accessing Web content related to information transmission media such as broadcasts or publications. It displays objects called “VisionMarks” that indicate Web content linked to the information transmission medium being viewed by the user. Users can use VisionMarks to refer to the linked Web content, and can store or send VisionMarks to other users. This allows users to easily make the best use of Web‐content‐linked information transmission media. We show how to implement an Internet application linking information transmission media with Web content by using VisionMarks. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(6): 20–30, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10606
Smoothing a discrete hazard function for the number of patients colonized with Methicillin‐resistantStaphylococcus Aureusin an intensive care unit
Authors: Ismail Noor Azina , Pettitt A. N. 
Published: April 2004

AbstractA new method for estimating the time to colonization of Methicillin‐resistantStaphylococcus Aureus(MRSA) patients is developed in this paper. The time to colonization of MRSA is modelled using a Bayesian smoothing approach for the hazard function. There are two prior models discussed in this paper: the first difference prior and the second difference prior. The second difference prior model gives smoother estimates of the hazard functions and, when applied to data from an intensive care unit (ICU), clearly shows increasing hazard up to day 13, then a decreasing hazard. The results clearly demonstrate that the hazard is not constant and provide a useful quantification of the effect of length of stay on the risk of MRSA colonization which provides useful insight. Copyright © 2004 John Wiley & Sons, Ltd.