bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and ionic conductivity of thermoplastic polyurethane electrolytes
Authors: Chen Wei‐Chih , Chen Hsuan‐Hsu , Wen Ten‐Chin , Digar Mohanlal , Gopalan A. 
Published: November 2003

AbstractThermoplastic polyurethane (TPU) with a mixture of soft segments [poly(ethylene glycol) (PEG) and poly(tetramethylene glycol) (PTMG)], denoted TPU‐M, was prepared as an ion‐conducting polymer electrolyte. TPUs with PEG and PTMG as soft segments were also synthesized individually as polymer electrolytes. The changes in the morphology and ion conductivity of the phase‐segregated TPU‐based polymer electrolytes as a function of the lithium perchlorate concentration were determined with differential scanning calorimetry, Fourier transform infrared spectroscopy, alternating‐current impedance, and linear sweep voltammetry measurements. Both solid and gelatinous polymer electrolytes were characterized in this study. The effect of temperature on conductivity was studied. The conductivity changes revealed the combined influence of PTMG and PEG units in TPU‐M. The swelling characteristics in a liquid electrolyte and the dimensional stability were evaluated for the three TPUs. Because of its dimensional stability and ionic conductivity, the TPU system containing both PEG and PTMG as soft segments was found to be more suitable for electrolyte applications. A room‐temperature conductivity of approximately 1 × 10−4 was found for TPU‐M containing 50 wt % liquid electrolyte. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1154–1167, 2004
Structural effect of emulsifiers on the emulsion stability of a water/benzene mixture
Authors: Saito Reiko , Mitani Shogo , Saito Maki 
Published: November 2003

AbstractCore–shell‐type microspheres with microphase‐separated shells of polystyrene (PS) and poly(ethylene glycol) (PEG) (microsphereblock: molar ratio: PS/PEG 49.1/45.9 mol %; Mw: PS chain: 1.07 × 104, PEG chain 1.0 × 104; the ratio of arm numbers of PEG to PS: 1.0; microspheregraft: molar ratio: PS/PEG 33.8/55.9 mol %; Mw: PS chain: 1.54 × 104, PEG chain 1.0 × 104, the ratio of arm numbers of PEG to PS: 2.55) were synthesized by crosslinking of spherical domains of poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(4‐vinyl pyridine) (P4VP) of the microphase‐separated films of poly(ethylene glycol)‐block‐poly(2‐hydroxyethyl methacrylate)‐block‐polystyrene triblock terpolymer (Mn: 2.18 × 104; molar ratio: PS 49.1 mol %, PHEMA 5.0 mol %, PEG 45.9 mol %) and polystyrene‐block‐[poly(4‐vinyl pyridine)‐graft‐poly(ethylene glycol)] block–graft copolymer (Mn: 4.56 × 104; molar ratio: PS 33.8 mol %, P4VP 10.3 mol %, PEG 55.9 mol %; branch number of PEG: 2.55), respectively. The structures of microphase‐separated films were investigated by transmission electron microscopy and small‐angle X‐ray scattering. The effects of the arm number ratio of PS to PEG and the total arm number on the stability of the water/benzene emulsion were investigated. The emulsion stability of oil in water was improved by using the microsphere synthesized with the microspheregraft. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 321–331, 2004
Synthesis, characterization, and antibacterial activity of metal‐containing polyurethanes
Authors: Jayakumar R. , Lee Y.‐S. , Rajkumar M. , Nanjundan S. 
Published: November 2003

AbstractMetal salts of mono(hydroxyethoxyethyl)phthalate [M(HEEP)2] (M = Ca2+, Cd2+, and Pb2+) were synthesized by the reaction of diethylene glycol, phthalic anhydride, and metal acetates. A series of metal‐containing polyurethanes (PUs) were synthesized by the reaction of hexamethylene diisocyanate or tolylene 2,4‐diisocyanate with Ca2+, Cd2+, and Pb2+ salts of mono(hydroxyethoxyethyl)phthalate using di‐n‐butyltin dilaurate as a catalyst. The PUs were well characterized by FTIR, 1H, and 13C NMR, solid‐state 13C‐CP‐MAS NMR, viscosity, solubility, elemental, and X‐ray diffraction studies. Thermal properties of the polymers were also studied by using thermogravimetric analysis and differential scanning calorimetry. The antibacterial activities of these polyurethanes have also been investigated by using the agar diffusion method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 288–295, 2004
Study of motional processes in polymer blends composed of isotactic polypropylene and ethylene–propylene–diene monomer rubber by broad‐line 1H‐NMR
Authors: Olčák Dušan , Onufer Jozef , Mucha L'ubomír , Raab Miroslav , Spěváček Jiří 
Published: November 2003

AbstractThe broad‐line 1H‐NMR study of the polymer blend composed of isotactic polypropylene and ethylene–propylene–diene monomer rubber was carried out. The NMR measurements were performed on the samples of the polymer blend and on the components of the blend in the temperature range covering the glass‐transition regions of all studied polymers. Conclusions were drawn from the temperature dependencies of the second moment M2 and of the data obtained by the decomposition of the spectra into the components related to the motionally distinct regions of the partially crystalline polymer. The mass fractions of the amorphous, intermediate, and crystalline domains and the widths of the spectra related to the particular phases were computed from the spectra. A double glass transition was revealed for the polymer blend. Different mechanisms of the motional processes related to the glass transition were deduced from the data. The gradual increase of the number of the chains and the enhancement of the chain mobility within noncrystalline regions of the polymer blend are responsible for the motion related to the lower glass transition and only transformation of the hindered motion into free motion was found in the temperature region of the upper glass transition. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 247–252, 2004
Novel sulfonium salts as thermal and photoinitiators for epoxide and acrylate polymerizations
Authors: Takahashi Eiji , Sanda Fumio , Endo Takeshi 
Published: November 2003

AbstractNovel sulfonium salts, 1‐naphthylmethyl‐, cinnamyl‐, 9‐fluorenyl tetramethylene sulfonium hexafluoroantimonates, and dimethylsulfonium hexafluoroantimonates, were synthesized by the reaction of tetrahydrothiophene and dimethylsulfide with the corresponding bromides or chloride, followed by anion exchange with KSbF6. These sulfonium salts polymerized epoxy monomers at a temperature lower than previously reported for benzyltetramethylenesulfonium hexafluoroantimonate. They initiated radical photopolymerization as well as cationic polymerization. The photopolymerization was accelerated by the addition of aromatic compounds such as p‐methoxyphenol, 4‐methoxy‐1‐naphthol, 2‐ethyl‐9,10‐dimethoxyanthracene, N‐ethylcarbazole, and phenothiazine as photosensitizers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 589–597, 2004
Preparation and properties of keratin–poly(vinyl alcohol) blend fiber
Authors: Katoh Kazunori , Shibayama Mikio , Tanabe Toshizumi , Yamauchi Kiyoshi 
Published: November 2003

AbstractKeratin–poly(vinyl alcohol) (PVA) blend fibers containing 13–46 wt % of –SSONa+ (S‐sulfo) keratin were prepared by the wet‐spinning technique. They were formed by dehydration of an aqueous solution of S‐sulfo keratin and PVA (spinning dope) in a coagulation bath of sodium sulfate–saturated solution and subsequently drawn. Keratin–PVA fibers showed higher tenacity than that of wool, presumably originating from the high mechanical strength of the PVA component. The heat treatment at about 200°C improved the waterproof characteristics such as shrinkage of keratin–PVA fibers more conspicuously than did PVA fibers. That is, after heat treatment at 195°C for 10 min, keratin–PVA blend fiber shrank 20% in water at 60°C, whereas PVA fiber shrank 56%. Differential thermal analysis suggested the crosslinking of disulfide bonds between keratin molecules during the heat treatment, whereas the additional crystallization of PVA component was not observed. Adsorption of heavy metal and toxic gas to keratin–PVA fibers was also investigated. Keratin–PVA fiber was found to adsorb Ag+ and formaldehyde gas more efficiently than PVA. Thus, blends of keratin and PVA were advantageous for both polymer fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 756–762, 2004
Continuous polymerization in tubular reactors with prepolymerization: Analysis using two‐dimensional phenomenological model and hybrid model with neural networks
Authors: Nogueira André L. , Lona Liliane M. F. , Machado Ricardo A. F. 
Published: November 2003

AbstractContinuous polymerization processes have advantages when large amounts of product are required; moreover, higher quality can be obtained because of the elimination of variability between batches. Tubular reactors are economically attractive because of their simple geometry and high heat exchange area; however, they are not commonly used for commercial purposes, mainly because of the large radial profiles. This study elucidates the operation of this kind of reactors in three different ways: first a detailed two‐dimensional mathematical model was developed, in which a complete visualization of all axial and radial profiles is possible, allowing a safe analysis at different operating conditions. In a second step a system composed of a continuously stirred tank reactor in series with a tubular reactor was used. A reduction in radial profiles can be clearly observed when prepolymerization is taken into account, improving both the homogeneity and the end properties of the polymer. In a third approach neural networks (NNs) were used in parallel with a one‐dimensional model. The objective of this study was to illustrate how NNs can improve the prediction capability when it is not possible to build a reliable model because of uncertainties in parameters and incomplete knowledge of the system. The NNs generated good results, showing that the hybrid model was able to accurately simulate the reactor, even when uncertainty in kinetic and diffusional parameters was imposed to the model. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 871–882, 2004
Surfactant‐free thermochromic hydrogel system: PVA/borax gel networks containing pH‐sensitive dyes
Authors: Chung Woo Young , Lee Sang Min , Koo Sang Man , Suh Dong Hack 
Published: November 2003

AbstractThe well‐known pH‐indicators, phenolphthalein and bromothymol blue, exhibit an outstanding thermochromism, when they are embedded in aqueous polyvinyl alcohol/borax gel networks. The color of phenolphthalein in hydrogels changes gradually from colorless at 20°C to dark red at 70°C. The pH change in a hydrogel system was from 8.0 to 8.9 with increasing temperature. In the case of bromothymol blue, the color was optically clear green at room temperature and changed to clear blue with increasing temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 890–893, 2004
Morphology–composition–processing relationships in poly(methyl methacrylate)–polytriethylene glycol dimethacrylate shrinkage‐controlled blends
Authors: Velázquez R. , Ceja I. , Guzmán J. , Castaño V. M. 
Published: November 2003

AbstractAn innovative method to control shrinkage in polymer blends, by using N,N‐dimethyl‐p‐toluidine to produce phase separation in an acrylic system, was applied to synthesize polymer blends from polymethyl methacrylate (PMMA) and polytriethylene glycol dimethacrylate (PTEGDMA). The morphology of several compositions, as analyzed by scanning electron microscopy, reveals microdomains as a function of the specific composition, in contrast to conventional MMA–TEGDMA copolymers synthesized by thermal decomposition of benzoyl peroxide, used here as reference materials. Micro‐Raman and DSC analyses were also carried out to support the electron microscopy results as well. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1254–1260, 2004
Synthesis, conformation, and immunosuppressive activity of CLX and its analogues
Authors: Ruchala P. , Picur B. , Lisowski M. , Cierpicki T. , Wieczorek Z. , Siemion I.Z. 
Published: November 2003

AbstractThe CLX peptide isolated from flax seed has a sequence cyclo‐(PPFFILLX), where X is a nonproteinaceous amino acid residue, (2S,4R) 4‐amine‐N‐methylproline. Picur, B.; Lisowski, M.; Siemion, I.Z. Letters Pept Sci 1998, 5, 183–187. The structure of X strongly suggests that this natural amino acid plays a role of the dipeptide moiety with a nonplanar cis peptidomimetic bond. The X residue contains two asymmetrical carbons and thus can appear in four configurations: (2S,4R), (2S,4S), (2R,4S), and (2R,4R). All four diastereoisomers of X were synthesized and characterized as trifluoroacetates of 4‐phtalimido‐N‐methylproline benzylamides. Their full physicochemical characteristics are presented in this article. The synthesis of linear and cyclic analogues of CLX containing all four possible diastereoisomers of X was performed. Additionally, analogues with γ‐aminobutyric acid (GABA) and glycyl‐N‐methyl‐glycine dipeptide [G(Me)G] substituted for X were synthesized. The obtained peptides were purified using HPLC, examined by ESI/MS, and then studied by CD spectroscopy. They were also tested for immunosuppressive activity (PFC in vitro). All of them revealed diverse immunosuppressive activity, however, lower than that of cyclolinopeptide A (CLA) Wieczorek, Z.; Bengtsson, B.; Trojnar, J.; Siemion, I.Z. Peptide Res 1991, 4, 275–283. and cyclosporine A (CsA). Ellis, G.P.; West, G.B. Progress Med Chem 1988, 25, 1–33. The structure of CLX with (2S,4R) 4‐amino‐N‐methylproline was determined by 2‐D NMR methods. All amide bonds are in the trans configuration. The cis peptidomimetic group δ‐CH2‐N(CH3)‐ is exposed to the outside of the CLX molecule. The peptide contains two loops similar to β‐turns of type IV. Chou, P.Y.; Fasman, G.D. J Mol Biol 1977, 115, 136–715 and has the extended shape flanked by F3 and L7 residues with significant side chain flexibility. © 2003 Wiley Periodicals, Inc. Biopolymers 70: 497–511, 2003
Structural alterations of enkephalins in the presence of GM1 ganglioside micelles
Authors: Chatterjee Chiradip , Mukhopadhyay Chaitali 
Published: November 2003

AbstractThe enkephalins are endogenous neurotransmitters and bind with high affinity at the δ‐receptor. Gangliosides, the major glycans of nerve cells, known to interact both with receptors and ligands on the cell surface, have been implicated to modulate the actions of opioid receptors by allosteric regulation (Wu, G.; Lu, Z. H.; Wei, T. J.; Howells, R. D.; Christoffers, K.; Leeden R. W. Ann NY Acad Sci 1998, 845, 126–138). We have studied the interactions between enkephalins and monosialylated ganglioside GM1 using NMR spectroscopy and fluorescence. The structural models of enkephalins in the presence of GM1 micelles were generated using two‐dimensional 1H‐ROESY experiments along with restrained molecular dynamics simulations. We report a conformational alteration of enkephalins in the presence of GM1 micelles. © 2003 Wiley Periodicals, Inc. Biopolymers 70: 512–521, 2003
Incidence trends of adult primary intracerebral tumors in four Nordic countries
Authors: Lönn Stefan , Klaeboe Lars , Hall Per , Mathiesen Tiit , Auvinen Anssi , Christensen Helle C. , Johansen Christoffer , Salminen Tiina , Tynes Tore , Feychting Maria 
Published: November 2003

AbstractBrain tumors are some of the most lethal adult cancers and there is a concern that the incidence is increasing. It has been suggested that the reported increased incidence can be explained by improvements in diagnostic procedures, although this has not been totally resolved. The aim of our study was to describe the incidence trends of adult primary intracerebral tumors in four Nordic countries during a period with introduction of new diagnostic procedures and increasing prevalence of mobile phone users. Information about benign and malignant primary intracerebral tumor cases 20–79 years of age was obtained from the national cancer registries in Denmark, Finland, Norway and Sweden for the years 1969–98 and estimates of person‐years at risk were calculated from the information obtained from national population registries. Annual age standardized incidence rates per 100,000 person‐years were calculated and time trends analyses were carried out using Poisson regression. The overall incidence of all intracerebral tumors ranged from 8.4–11.8 for men and 5.8–9.3 for women, corresponding to an average annual increase of 0.6% for men (95% confidence interval [CI] = 0.4, 0.7) and 0.9% for women (95% CI = 0.7, 1.0). The increase in the incidence was confined to the late 1970s and early 1980s and coinciding with introduction of improved diagnostic methods. This increase was largely confined to the oldest age group. After 1983 and during the period with increasing prevalence of mobile phone users, the incidence has remained relatively stable for both men and women. © 2003 Wiley‐Liss, Inc.
Lymphoproliferative disorders in autoimmune diseases in Japan: Analysis of clinicopathological features and Epstein‐Barr virus infection
Authors: Hoshida Yoshihiko , Tomita Yasuhiko , Zhiming Dong , Yamauchi Amane , Nakatsuka Shin‐ichi , Kurasono Yoshiko , Arima Yasuhiro , Tsudo Mitsuru , Shintaku Masayuki , Aozasa Katsuyuki 
Published: November 2003

AbstractLymphoproliferative disorders (LPD) occasionally develop in individuals with immune deficiencies such as immunosuppressive conditions and autoimmune diseases (AID). In our study, the clinicopathologic features and virus status were analyzed in 53 cases with LPD developing in rheumatoid arthritis (RA) and other AID. AID in only 4 of 53 patients had been treated with some sort of immunosuppressive therapy, including methotrexate. Median age at the diagnosis of LPD in AID was 60 years old with marked female predominance (M/F = 0.4). The median interval between the onset of AID and LPD development was 45 months, and longer in RA patients than in other AID (p< 0.01). The primary site of lymphoma was nodal in 21 cases and extra‐nodal in 24, with clinical Stage I in 17, II in 5, III in 13, and IV in 13. Immunohistochemistry showed that 39 cases were B cell type, 10 were T cell type and 4 were Hodgkin lymphoma (HL). Then majority of B cell cases were diffuse large B cell lymphomas, and 2 were diffuse polymorphic type. EBER‐1in situhybridization for Epstein‐Barr virus (EBV) showed positive signals in tumor cells in 16 of 53 (30.2%) cases. The EBV‐positive rate in T cell LPD (70%) was much higher than that in B cell LPD (12.8%) (p< 0.01). All 4 cases of HL were EBV‐positive. Immunohistochemistry showed a latency II pattern of EBV infection (LMP‐1+and EBNA‐2−). Five‐year overall survival rate was 33%. Multivariate analysis showed that only type of AID was an independent factor for survival of patients,i.e., LPD in RA showed the most favorable prognosis. In conclusion, LPD in AID generally shared common features with sporadic LPD except for a much higher EBV‐positive rate in T cell LPD. © 2003 Wiley‐Liss, Inc.
On the flexibility of β‐peptides
Authors: Beke Tamás , Csizmadia Imre G. , Perczel András 
Published: November 2003

AbstractThe full conformational space was explored for an achiral and two chiral β‐peptide models: namely For‐β‐Ala‐NH2, For‐β‐Abu‐NH2, and For‐β‐Aib‐NH2. Stability and conformational properties of all three model systems were computed at different levels of theory: RHF/3‐21G, B3LYP/6‐311++G(d,p)//RHF/3‐21G, B3LYP/6‐311++G(d,p), MP2//B3LYP/6‐311++G(d,p), CCSD//B3LYP/6‐311++G(d,p), and CCSD(T)//B3LYP/6‐311++G(d,p). In addition,ab initioE = E(φ, μ, ψ) potential energy hypersurfaces of all three models were determined, and their topologies were analyzed to determine the inherent flexibility properties of these β‐peptide models. Fewer points were found and assigned than expected on the basis of Multidimensional Conformational Analysis (MDCA). Furthermore, it has been demonstrated, that the four‐dimensional surface,E = E(φ, μ, ψ), can be reduced into a three‐dimensional one:E = E[φ,f(φ), ψ]. This reduction of dimensionality of freedom of motion suggests that β‐peptides are less flexible than one would have thought. This agrees with experimental data published on the conformational properties of peptides composed of β‐amino acid residues. © 2003 Wiley Periodicals, Inc. J Comput Chem 25: 285–307, 2004
A novel pH sensitive porous membrane carrier for various biomedical applications based on pHEMA/chitosan: preparation and its drug release characteristics
Authors: Bayramoğlu Gülay , Arıca M. Yakup 
Published: November 2003

AbstractThe synthetic hydrogels based on pHEMA have been widely studied and used in biomedical fields. Numerous techniques exist for entrapment of drugs or proteins in the hydrogels. The suitable biomaterials for biomedical applications include poly(hydroxyethyl methacrylate), (pHEMA), and chitosan. In this work, a novel pH sensitive interpenetrating polymer networks (IPNs) were prepared in the membrane form by using 2‐hydroxyethyl‐methacrylate monomer (HEMA) and chitosan via UV initiated photo‐polymerization in the presence of an initiator (i.e., α‐α;′‐azo‐isobutyronitrile; AIBN). UV‐free‐radical polymerization techniques are often used to synthesize hydrogels for controlled release applications. A series of HEMA and chitosan IPNs hydrogels were prepared and the equilibrium swelling studies were conducted to investigate swelling behaviors of the membrane according to the pH of the swelling medium. The swelling properties of the membrane were changed with the medium pH. The equilibrium water uptake is reached in about 60 min. The pHEMA/chitosan membrane thickness and density was measured to be 600 μm and 1.26 g cm−3, respectively. Antibiotic release experiments were also performed with amoxicillin loaded pHEMA/chitosan membrane in physiological saline solution. The IPNs membrane loaded with 100 mg antibiotic (i.e., amoxicillin) g hydrogel released around 80% of the amoxicillin in 10 h at pH 7.4. The presented well‐characterized novel pHEMA/chitosan membrane is a potential candidate for transdermal antibiotic carrier or a support in bioseparation.
Conformal chemoradiation for primary and metastatic liver malignancies
Authors: Dawson Laura A. , McGinn Cornelius J. , Lawrence Theodore S. 
Published: November 2003

AbstractHistorically, radiation therapy has played a minor role in the management of patients with unresectable primary hepatobiliary malignancies and liver metastases from colorectal cancer. This can be attributed chiefly to the low tolerance of the whole liver to radiation. Three‐dimensional radiation planning techniques have allowed much higher doses of radiation to be delivered to focal liver tumors, while sparing the majority of the normal liver. When combined with fluorodeoxyuridine (FUdR), high‐dose focal liver radiation is associated with excellent response rates, local control, and survival in patients with large unresectable tumors. There appears to be a radiation dose response for intrahepatic malignancies. Advancements in tumor imaging, radiation techniques that can safely deliver higher doses of radiation, novel tumor radiation sensitizers, and normal‐tissue radioprotectors should substantially improve the outcome of patients with unresectable intrahepatic malignancies treated with chemoradiation. Semin. Surg. Oncol. 21:249–255, 2003. © 2003 Wiley‐Liss, Inc.