bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibration damping materials based on interpenetrating polymer networks of carboxylated nitrile rubber and poly(methyl methacrylate)
Authors: Manoj N. R. , Chandrasekhar L. , Patri M. , Chakraborty B. C. , Deb P. C.
Published: October 2002

Interpenetrating polymer networks (IPNs) based on carboxylated nitrile rubber (XNBR) and poly(methyl methacrylate)s were synthesized. Crosslinked XNBR was swollen in methyl methacrylate containing benzoyl peroxide as initiator and tetraethylene glycol dimethacrylate as crosslinking agent. The compositions of the IPNs were varied by changing the swelling time of the rubber in the methacrylate monomer. The dynamic mechanical properties of the IPNs were studied. The dynamic mechanical properties in the range 1–105 Hz were obtained by the time‐temperature superposition of the data under multifrequency mode, which indicated high tan δ with good storage modulus in the entire frequency range. This indicates the suitability of these IPNs as vibration and acoustic dampers. Copyright © 2002 John Wiley & Sons, Ltd.
Telomerase as a prognostic marker in breast cancer: high‐throughput tissue microarray analysis of hTERT and hTR
Authors: Poremba Christopher , Heine Bernhard , Diallo Raihanatou , Heinecke Achim , Wai Daniel , Schaefer Karl‐Ludwig , Braun Yvonne , Schuck Andreas , Lanvers Claudia , Bànkfalvi Àgnes , Kneif Sören , Torhorst Joachim , Zuber Markus , Köchli Ossi R. , Mross Frank , Dieterich Holger , Sauter Guido , Stein Harald , Fogt Franz , Boecker Werner
Published: October 2002

Telomerase activity (TA) has been shown to correlate with poor clinical outcome in various tumour entities, indicating that tumours expressing this enzyme may be more aggressive and that TA may be a useful prognostic marker. For breast cancer, however, TA is a controversial prognostic marker; whereas some studies suggest an association between TA and disease outcome, others do not find this association. This study used tissue microarrays (breast carcinoma prognosis arrays) containing 611 samples (each 0.6 mm in diameter) from the tumour centre of paraffin‐embedded breast carcinomas to analyse the catalytic subunit of telomerase, human telomerase reverse‐transcriptase (hTERT), and the internal RNA component (hTR), which are the core components of the telomerase holoenzyme complex. hTERT protein expression was obtained by immunohistochemistry (human anti‐telomerase antibody Ab‐2, Calbiochem), and hTR RNA was measured by radioactive in situ hybridization. hTERT and hTR expression were determined semi‐quantitatively and graded (scores 1–4). Clinical data, such as histological subtype, pT stage, tumour diameter, pN stage, BRE grade, tumour‐specific survival (in months), patient's age and others, were available for statistical analysis. A statistically significant correlation was found between tumour‐specific survival (overall survival) and hTERT expression (p < 0.0001) or hTR expression (p = 0.00110). Tumours with higher scores (scores 3, 4) for hTR and/or hTERT were associated with a worse prognosis. In multivariate analysis, hTERT expression was an independent prognostic factor. Previous studies, focusing on analysis of TA in smaller numbers of fresh‐frozen breast carcinomas by the TRAP assay, gave controversial results with respect to TA as a prognostic marker. Using tissue microarrays from 611 breast carcinomas, this study has demonstrated that increased expression levels of the telomerase core components, hTERT and hTR, are associated with lower overall survival. These findings suggest that TA should be included in future validation studies as a prognostic marker in breast cancer. Copyright © 2002 John Wiley & Sons, Ltd.
Microsatellite analysis of breast carcinoma and corresponding local recurrences
Authors: Regitnig Peter , Moser Renate , Thalhammer Michael , Luschin‐Ebengreuth Gero , Ploner Ferdinand , Papadi Helmtraud , Tsybrovskyy Oleksiy , Lax Sigurd F.
Published: October 2002

Local recurrence is a serious complication of breast carcinoma that reduces quality of life and influences prognosis. The aim of this study was to determine whether local recurrences of breast carcinoma are genetically related to the primary tumours. Forty cases of locally recurrent breast carcinomas (median onset: 3.6 years after primary surgery) were analysed: 22 patients had undergone breast‐conserving therapy and 18 mastectomy. Eighteen microsatellites on chromosomes 2p, 3p, 5q, 10q, 11p, 11q, 13q, 17q, 17p, 18p were amplified by PCR using fluorescent‐labelled primers, automatically detected after polyacrylamide gel electrophoresis and analysed for loss of heterozygosity (LOH) or microsatellite instability (MSI). Follow‐up data were available for 39 cases with a median value of 89 months. All LOH and MSI found in the primary tumours were also present in the corresponding recurrences, indicating that they are genetically related to the primary tumours and not secondary malignancies in the same breast. MSI was found in three cases, of which one harboured MSI at more than two loci. The median value of LOH per case was significantly higher in the recurrent (four per case) compared to the primary tumours (two per case; p < 0.001, Mann–Whitney test), reflecting the genotype of tumour progression. Early local recurrence was associated with specific LOH for TP53.15 (p = 0.018, log‐rank test) in the primary tumours. LOH on D13S1699 or D17S855 was associated with lymph node metastases (p = 0.024 and p = 0.019, respectively; chi‐square test). In addition, tumour grade, lack of oestrogen or progesterone receptor expression, young patient age and early appearance of local recurrence significantly correlated with poor survival. The development of local recurrence despite clear resection margins may result from residual DCIS distant from the invasive carcinoma, homing of circulating tumour cells, or genetically altered, histologically normal breast tissue not immediately adjacent to the invasive carcinoma. Copyright © 2002 John Wiley & Sons, Ltd.
Quantification of CK20 gene and protein expression in colorectal cancer by RT‐PCR and immunohistochemistry reveals inter‐ and intratumour heterogeneity
Authors: Lassmann Silke , Bauer Markus , Soong Richie , Schreglmann Joachim , Tabiti Karim , Nährig Jörg , Rüger Rüdiger , Höfler Heinz , Werner Martin
Published: October 2002

Cytokeratin 20 (CK20) is an epithelial protein expressed almost exclusively in the gastrointestinal (GI) tract and is widely used as immunohistochemical marker for routine diagnosis. In contrast, CK20 gene expression is not an established marker for the classification of tumours and the detection of disseminated cancer cells in colorectal cancer. Recently, real‐time reverse transcriptase polymerase chain reaction (RT‐PCR) has provided the means for reproducible and quantitative investigation of molecular markers. This report directly compares CK20 mRNA and protein expression in serial sections of archival, formalin‐fixed, paraffin‐embedded (FFPE) colorectal adenocarcinomas. CK20 expression was detected by immunohistochemistry (IHC) in 60/63 (95.2%) cases, by conventional RT‐PCR in 58/60 (96.7%) and by quantitative RT‐PCR using the LightCycler® (LightCycler® is a trademark of a Member of the Roche Group) System in 29/32 (90.6%) microdissected cases, one case yielding variable results. Despite the high detection rate of all three techniques, marked heterogeneity of CK20 expression was seen between different cases and also within individual cases. CK20 expression profiles were not related to particular histopathological features of the tumours. A good correlation (r = 0.8964) was found between CK20 mRNA and protein expression by comparing quantitative RT‐PCR with IHC in 32 cases. This was also true for selected heterogeneous tumour cells within individual cases. Both RT‐PCR and IHC are therefore valuable tools for CK20 detection in colorectal adenocarcinoma, with real‐time RT‐PCR providing supplementary quantitative information. This suggests a promising supportive role for quantitative RT‐PCR in molecular pathology. Copyright © 2002 John Wiley & Sons, Ltd.
E2F1 selects tumour cells for both life and death
Authors: Wyllie Andrew H
Published: October 2002

E2F1 is a transcription factor involved in both cell cycle progression and apoptosis. Perhaps surprisingly, these two processes are closely related, and the choice between them appears to be made on the basis of the aggregate of signals flowing into the cell at the time. This may be the means whereby normal cells tune their threshold for apoptosis with respect to the availability of external growth factors, so that cells that are supernumerary to the tissue's needs at the time can be immediately deleted. In many tumours, however, the pathways that link E2F1 activity to apoptosis have been interrupted, sometimes at multiple points. Non‐small‐cell lung carcinoma provides a striking example of this, with the result that expression of E2F1 in these tumours does not correlate with apoptosis but is a good surrogate marker for replicative status. This relationship does not necessarily pertain in other tumour types. Molecules such as E2F1 lie at the core of very significant cell fate decisions, but they are part of a complex matrix of interactions, all of which must be surveyed before interpretation in terms of tumour behaviour is possible. Microarray analysis may provide a way to do this. In the future, however, such interpretations, including predictions of therapeutic response, may be possible through interrogation of the status of a relatively limited number of molecules. Those that preside over critical cellular decision forks (such as the choice between proliferation or death) are good candidates for this role. E2F1 clearly qualifies as one member of this group. Copyright © 2002 John Wiley & Sons, Ltd.
Serious ventricular arrhythmias among users of cisapride and other QT‐prolonging agents in the United States
Authors: Enger Cheryl , Cali Clorinda , Walker Alexander M.
Published: October 2002

Purpose

To evaluate the risk of serious ventricular arrhythmia (SVA) with cisapride use in the United States.

Methods

The study population included 28 078 patients under the age of 65 years who received cisapride between 1993 and 1998 with no history of antiarrhythmia treatment. Each follow‐up day was classified according to use of cisapride and other factors. Outcomes of SVAs were identified using medical claims records and National Death Index search, and confirmed by medical record review. Rates of events were calculated for time on and off cisapride. Poisson regression analysis was used to calculate adjusted rate ratios.

Results

There were 23 cases of SVAs; 10 during periods of cisapride use and 13 during periods of non‐use. The adjusted rate ratio comparing SVA events in cisapride use time to non‐use time was 1.60 (95%CI: 0.67–3.82), and that identified for the other QT‐prolonging drugs was 1.60 (95%CI: 0.65–3.98).

Conclusions

The evidence for an increased risk of SVAs associated with cisapride was equivocal after taking observation time on and off cisapride into account, and adjusting for risk factors, though we cannot exclude the possibility of a 3.8‐fold increased risk. Overall, the plausible risks of cisapride were similar to those of other QT‐prolonging drugs. Copyright © 2002 John Wiley & Sons, Ltd.
Superbasic properties of the SN functional group
Authors: Raczyńska Ewa D. , Woźniak Krzysztof , Dolecka Ewa , Darowska Małgorzata
Published: October 2002

Quantum‐chemical calculations (ab initio and semiempirical) were performed for neutral and monoprotonated model compounds of general formula H
iXNH (where X is C, N, S or P and i = 1, 2 or 3) and thermodynamic parameters for the protonation reaction were calculated. All derivatives belong to the family of nitrogen bases. The basicity of H2SNH is larger than that of H2CNH and lower than that of H3PNH, indicating that derivatives with the SN group can form a ‘bridge’ between guanidines and phosphazenes in the gas‐phase superbasicity scale. The basicity of HNNH is lower than that of H2CNH. Topological analysis of electron density distributions in +H3SNH, H2SNH2+ and two neutral isomers of H2SNH showed significant differences in the properties of critical points on N‐ and S‐protonations. All parameters such as ρ, laplacian atomic volumes and dipoles and also bond properties are affected on protonation. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group. XII. Copolymerization of vinylidene fluoride with 2,3,3‐trifluoroprop‐2‐enol
Authors: Guiot J. , Ameduri B. , Boutevin B.
Published: October 2002

An improved synthesis of 2,3,3‐trifluoroprop‐2‐enol (FA1) and its copolymerization in solution with vinylidene fluoride (VDF, or 1,1‐difluoroethylene) initiated by tert‐butyl peroxypivalate are presented. A new synthesis of FA1, with NaH and lithium diisopropylamine as bases, from 2,2,3,3‐tetrafluoropropanol is described. A series of nine copolymerization reactions were investigated from initial [VDF]0/[FA1]0 molar ratios of 9.1/90.9 to 94.2/5.8. The copolymer compositions were calculated via 19F NMR spectroscopy. From the Tidwell–Mortimer method, the reactivity ratios of both comonomers were determined (rFA1 = 0.11 ± 0.22 and rVDF = 0.83 ± 0.77 at 50°C), and they showed an azeotropic point. Alfrey and Price's Q and e values of FA1 were calculated to be 0.0178 (from QVDF = 0.008), 0.039 (from QVDF = 0.015), and 0.275 (from QVDF = 0.036) and 2.74 (vs eVDF = 1.20), 2.04 (vs eVDF = 0.50), and 1.94 (vs eVDF = 0.4), respectively, and they indicated that FA1 is an electron‐accepting monomer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3634–3643, 2002
Synthesis and characterization of spirobifluorene‐based polyimides
Authors: Chou Chia‐Hung , Reddy D. Sahadeva , Shu Ching‐Fong
Published: October 2002

The synthesis and properties of organosoluble aromatic polyimides, containing spiro‐skeletal units in the polymer backbone on the basis of the spiro‐diamine monomer, 2,2′‐diamino‐9,9′‐spirobifluorene, are described. In the case of the spiro segment, the two fluorene rings are orthogonally arranged and connected through a tetrahedral bonding carbon atom, the spiro center. As a consequence, the polymer chain is periodically zigzagged with a 90° angle at each spiro center. This structural feature minimizes interchain interactions and restricts the close packing of the polymer chains, resulting in amorphous polyimides that have good solubility in organic solvents. Compared with their fluorene‐based cardo analogues, the spirobifluorene‐based polyimides have an improved solubility. Furthermore, the main‐chain rigidity of the polyimide appears to be preserved because of the presence of the spiro structure, which restricts the free segmental mobility. As a result, these polyimides exhibit a high glass‐transition temperature (Tg's) and good thermal stability. The Tg's of these polyimides were in the range of 287–374 °C, and the decomposition temperatures in nitrogen for a 10% weight loss occurred at temperatures above 570 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3615–3621, 2002
Synthesis of polyphosphonates containing pendant chloromethyl groups by the polyaddition of bis(oxetane)s with phosphonic dichlorides
Authors: Minegishi Shouji , Tsuchida Shinji , Sasaki Masaki , Kameyama Atsushi , Kudo Hiroto , Nishikubo Tadatomi
Published: October 2002

The polyaddition of 4,4′‐bis[(3‐ethyl‐3‐oxetanyl)methoxy]biphenyl (4,4′‐BEOBP) and phenylphosphonic dichloride (PPDC) with quaternary onium salts as catalysts proceeded under mild reaction conditions to afford a polymer containing phosphorous atoms in its main chain. A polyphosphonate with a high number‐average molecular weight (10,300) was obtained by the reaction of 4,4′‐BEOBP and PPDC in the presence of tetraphenylphosphonium chloride (TPPC) in o‐dichlorobenzene at 130 °C for 24 h. The structure of the resulting polymer was confirmed with IR, 1H NMR, and 31P NMR spectroscopy. Furthermore, it was proved that the polyaddition of certain bis(oxetane)s with phosphonic dichlorides proceeded smoothly to give corresponding polyphosphonates with TPPC as the catalyst. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3835–3846, 2002
Proton‐conducting polymers based on benzimidazoles and sulfonated benzimidazoles
Authors: Asensio Juan Antonio , Borrós Salvador , Gómez‐Romero Pedro
Published: October 2002

A sulfonated derivative of polybenzimidazole is reported, and its properties are analyzed in comparison with related polybenzimidazole proton‐conducting materials. Poly(2,5‐benzimidazole), poly(m‐phenylenebenzobisimidazole), and poly[m‐(5‐sulfo)‐phenylenebenzobisimidazole] were prepared by condensation of the corresponding monomers in polyphosphoric acid. Several adducts of these polymers with phosphoric acid were prepared. The resulting materials were characterized by chemical analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis; also, the dc conductivity of doped and undoped derivatives was measured. Similar to what has been observed for the commercial polybenzimidazole polymer (also examined here for comparison), the title polymers exhibit high thermal stability. Furthermore, their doping with phosphoric acid leads to a significant increase in conductivity from less than 10−11 Scm−1 for the undoped polymers to 10−4 Scm−1 (both at room temperature) for their acid‐loaded derivatives. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3703–3710, 2002
Atom transfer radical polymerization of n‐butyl acrylate catalyzed by CuBr/N‐(n‐hexyl)‐2‐pyridylmethanimine
Authors: Zhang Huiqi , Van Der Linde Rob
Published: October 2002

The homogeneous atom transfer radical polymerization (ATRP) of n‐butyl acrylate with CuBr/N‐(n‐hexyl)‐2‐pyridylmethanimine as a catalyst and ethyl 2‐bromoisobutyrate as an initiator was investigated. The kinetic plots of ln([M]0/[M]) versus the reaction time for the ATRP systems in different solvents such as toluene, anisole, N,N‐dimethylformamide, and 1‐butanol were linear throughout the reactions, and the experimental molecular weights increased linearly with increasing monomer conversion and were very close to the theoretical values. These, together with the relatively narrow molecular weight distributions (polydispersity index ∼ 1.40 in most cases with monomer conversion > 50%), indicated that the polymerization was living and controlled. Toluene appeared to be the best solvent for the studied ATRP system in terms of the polymerization rate and molecular weight distribution among the solvents used. The polymerization showed zero order with respect to both the initiator and the catalyst, probably because of the presence of a self‐regulation process at the beginning of the reaction. The reaction temperature had a positive effect on the polymerization rate, and the optimum reaction temperature was found to be 100 °C. An apparent enthalpy of activation of 81.2 kJ/mol was determined for the ATRP of n‐butyl acrylate, corresponding to an enthalpy of equilibrium of 63.6 kJ/mol. An apparent enthalpy of activation of 52.8 kJ/mol was also obtained for the ATRP of methyl methacrylate under similar reaction conditions. Moreover, the CuBr/N‐(n‐hexyl)‐2‐pyridylmethanimine‐based system was proven to be applicable to living block copolymerization and living random copolymerization of n‐butyl acrylate with methyl methacrylate. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3549–3561, 2002
Spectroscopic characterization and preparation of low molecular, water‐soluble chitosan with free‐amine group by novel method
Authors: Nah Jae‐Woon , Jang Mi‐Kyeong
Published: October 2002

Low molecular, water‐soluble chitosan (LMWSC) with a free amine group was prepared by the novel salts‐removal method described in this study. A weight‐average molecular weight and degree of deacetylation (DDA) of LMWSC were determined by viscometry and Kina titration, resulting in 18,579 Da and 93% DDA, respectively. In the Fourier transform infrared spectroscopic, 1H NMR, and 13C NMR spectra the absorption band by the carboxyl group derived from lactic acid and the impurities formed in the enzymatic process disappeared or were significantly lower than that of the control chitosan. Also, from the 1H NMR and 13C NMR spectra the empirical value for the area ratio of the proton and carbon corresponds nearly to its theoretical values. The matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrum identified the difference in the two adjacent peaks as 161. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3796–3803, 2002
Synthesis and in vitro degradation of poly(N‐vinyl‐2‐pyrrolidone)‐based graft copolymers for biomedical applications
Authors: Brunius Carl F. , Edlund Ulrica , Albertsson Ann‐Christine
Published: October 2002

This work is devoted to the design of a novel family of hydrosoluble biomaterials: poly(N‐vinyl‐2‐pyrrolidone) (PVP)‐based graft copolymers. A synthesis route has been elaborated in which ω‐functionalized PVP is prepared via chain‐transfer radical polymerization, end‐group modified, and subsequently grafted onto a polyhydroxylated backbone, typically dextran or poly(vinyl alcohol). The resulting graft copolymer biomaterials are designed for use in various biomedical applications, particularly as materials with a stronger potential for plasma expansion than already existing products have. The graft copolymers are potentially degradable because the PVP grafts are connected to the polyol backbone via a hydrolytically labile carbonate or ester linkage. The degradation of the graft copolymers was performed in vitro over a period of 6 weeks. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3652–3661, 2002
Correlation between the tacticity and content of labile nondefect structures in poly(vinyl chloride)
Authors: Martinez Gerardo , Millan Jose Luis
Published: October 2002

The content of mm isotactic triads taking the GTTG− conformation for samples of poly(vinyl chloride) (PVC) fractions of different tacticities was measured through a substitution reaction with sodium benzenethiolate. This quantity changed linearly with the ratio of rmmmrx to mmmmrx (x = m or r), as accurately determined by 13C NMR spectroscopy. In a comparison of this correlation and that obtained between the thermal degradation stability and overall isotactic content, as studied previously, some novel evidence for the GTTG− conformation of a few mm triads, termini of isotactic sequences no shorter than one heptad as specific labile sites in PVC, was obtained. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3944–3949, 2002
Synthesis and characterization of hyperbranched polyimides with good organosolubility and thermal properties based on a new triamine and conventional dianhydrides
Authors: Chen Huan , Yin Jie
Published: October 2002

A triamine monomer, 1,3,5‐tris(4‐aminophenoxy)benzene (TAPOB), was synthesized from phloroglucinol and 4‐chloronitrobenzene, and it was successfully polymerized into soluble hyperbranched polyimides (HB PIs) with commercially available dianhydrides: 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 4,4′‐oxydiphthalic anhydride (ODPA), and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA). Different monomer addition methods and different monomer molar ratios resulted in HB PIs with amino or anhydride end groups. From 1H NMR spectra, the degrees of branching of the amino‐terminated polymers were estimated to be 0.65, 0.62, and 0.67 for 6FDA–TAPOB, ODPA–TAPOB, and BTDA–TAPOB, respectively. All polymers showed good thermal properties with 10% weight‐loss temperatures (T10's) above 505 °C and glass‐transition temperatures (Tg's) of 208–282 °C for various dianhydrides. The anhydride‐terminated HB PIs showed lower T10 and Tg values than their amino‐terminated counterparts. The chemical conversion of the terminal amino or anhydride groups of the 6FDA‐based polyimides into an aromatic imido structure improved their thermal stability, decreased their Tg, and improved their solubility. The HB PIs had moderate molecular weights with broad distributions. The 6FDA‐based HB PIs exhibited good solubility even in common low‐boiling‐point solvents such as chloroform, tetrahydrofuran, and acetone. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3804–3814, 2002
Reverse atom transfer radical solution polymerization of methyl methacrylate under pulsed microwave irradiation
Authors: Cheng Zhenping , Zhu Xiulin , Chen Gaojian , Xu Wenjian , Lu Jianmei
Published: October 2002

The reverse atom transfer radical polymerization (RATRP) of methyl methacrylate (MMA) was successfully carried out under pulsed microwave irradiation (PMI) at 69 °C with N,N‐dimethylformamide as a solvent and with azobisisobutyronitrile (AIBN)/CuBr2/tetramethylethylenediamine as an initiation system. PMI resulted in a significant increase in the polymerization rate of RATRP. A 10.5% conversion for a polymer with a number‐average molecular weight of 34,500 and a polydispersity index of 1.23 was obtained under PMI with a mean power of 4.5 W in only 52 min, but 103 min was needed under a conventional heating process (CH) to reach a 8.3% conversion under identical conditions. At different [MMA]0/[AIBN]0 molar ratios, the apparent rate constant of polymerization under PMI was 1.5–2.3 times larger than that under CH. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3823–3834, 2002
Effects of organophilic clay on the solvent‐maintaining capability, dimensional stability, and electrochemical properties of gel poly(vinylidene fluoride) nanocomposite electrolytes
Authors: Liu H. J. , Hwang J. J. , Chen‐Yang Y. W.
Published: October 2002

Four quaternary alkyl ammonium salts were used in an organophilic procedure, performed on montmorillonite clay, and resulted in intercalation in dimethylformamide (DMF) or ethylene carbonate (EC)/propylene carbonate (PC) as a cosolvent between poly(vinylidene fluoride) (PVdF) and the organophilic clay. An examination using X‐ray diffraction revealed that PVdF entered galleries of montmorillonite clay, and it exhibited exfoliation and intercalation phenomena when it was analyzed with transmission electron microscopy. Gel PVdF nanocomposite electrolyte materials were successfully prepared by the addition of the appropriate percentages of DMF or PC/EC as a cosolvent, organophilic clay, and lithium perchlorate to PVdF. The maximum ionic conductivity was 1.03 × 10−2 S/cm, and the materials exhibited better film formation, solvent‐maintaining capability, and dimensional stability than electrolyte films without added organophilic clays. The results of cyclic voltammetry testing showed that the addition of the organophilic clays significantly enhanced the electrochemical stability of the polymer electrolyte system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3873–3882, 2002
π‐Conjugated oligomers containing tropone in the main chain: Synthesis, characterization, and optical properties
Authors: Takagi Koji , Nishikawa Yukimi , Nishioka Naomi , Kunisada Hideo , Yuki Yasuo
Published: October 2002

The synthesis and characterization of tropone‐containing π‐conjugated oligomers were investigated. Two kinds of oligomers [1,4‐phenylene type (4a–4e) and 2,5‐thienylene type (5)] were successfully obtained by the Wittig polycondensation technique, in which the tropone content could be controlled by the monomer feed ratio for the 1,4‐phenylene‐type oligomers. The absorption maximum blueshifted and the emission intensity decreased with an increase in the tropone content in the oligomers. The emissive color could be tuned by the selection of the aromatic ring; that is, 4a–4e emitted orange‐yellow light and 5 emitted either orange‐yellow or red light according to the excitation wavelength. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3927–3937, 2002
Spatially heterogeneous dynamics during physical aging far below the glass transition temperature
Authors: Thurau Courtney T. , Ediger M. D.
Published: October 2002

Physical aging experiments after a deep quench were performed via an optical photobleaching technique to examine the evolution of the segmental dynamics of a polystyrene melt far below the glass transition temperature (Tg). Both rotational and translational diffusion measurements of dilute tetracene probes dispersed in the polymer matrix were monitored as a function of aging time. Following a temperature quench from Tg +2 °C deep into the glass (with isothermal aging temperatures ranging from Tg −15 to Tg −67 °C), either rotational or translational diffusion measurements were performed for up to 105 s of elapsed time. During this period, relaxation times for both observables were retarded by at least a factor of 3. Rotational and translational observables respond differently to the initial temperature quench and to the subsequent isothermal aging. These differences likely indicate that the dynamics responsible for physical aging in a quenched glass are spatially heterogeneous. Immediately following the quench, regions of faster mobility age toward equilibrium faster than regions of slower mobility. These findings compliment recent aging experiments close to Tg and bolster the conclusion that heterogeneous dynamics are important for the accurate description of physical aging. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2463–2472, 2002
Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na+‐montmorillonite
Authors: Krikorian Vahik , Kurian Mary , Galvin Mary E. , Nowak Andrew P. , Deming Timothy J. , Pochan Darrin J.
Published: October 2002

The feasibility of constructing polymer/clay nanocomposites with polypeptides as the matrix material is shown. Cationic poly‐L‐lysine · HBr (PLL) was reinforced by sodium montmorillonite clay. The PLL/clay nanocomposites were made via the solution‐intercalation film‐casting technique. X‐ray diffraction and transmission electron microscopy data indicated that montmorillonite layers intercalated with PLL chains coexist with exfoliated layers over a wide range of relative PLL/clay compositions. Differential scanning calorimetry suggests that the presence of clay suppresses crystal formation in PLL relative to the neat polypeptide and slightly decreases the PLL melting temperature. Despite lower crystallinity, dynamic mechanical analysis revealed a significant increase in the storage modulus of PLL with an increase in clay loading producing storage modulus magnitudes on par with traditional engineering thermoplastics. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2579–2586, 2002
Preliminary measurements on methane content in permafrost, Central Yakutia, and some experimental data
Authors: Brouchkov Anatoli , Fukuda Masami
Published: October 2002

The concentration of methane in air bubbles within permafrost was sampled from both alluvial deposits and ice wedges in Eastern Siberia. The values of methane concentration were as high as 6000 ppmv in both frozen soil and ice wedges. The anti‐proportional relationship between methane and carbon dioxide concentration values in permafrost was examined. Values of methane concentration in ice wedges are smaller than those in frozen soils. Values of total volumetric air content, water content and density were obtained by on‐the‐spot investigation. Increases of methane and carbon dioxide concentrations were detected in accordance with increases of water content of frozen soil. Geologically older permafrost contained higher values of methane concentration than younger permafrost. Samples of frozen soils were incubated at temperature −5°C in order to study possible methane production. A slow production in different soils was observed, although the experiments took a long time before measurable changes of methane content could be found. The rate of methane production decreases in time; therefore, long‐term forecasts of methane content in frozen soils are still problematical. Copyright © 2002 John Wiley & Sons, Ltd.
Acute renal failure in cystic fibrosis: Association with inhaled tobramycin therapy
Authors: Hoffmann Ingrid M. , Rubin Bruce K. , Iskandar Samy S. , Schechter Michael S. , Nagaraj Shashi K. , Bitzan Martin M.
Published: October 2002

We describe a 20‐year‐old patient with cystic fibrosis who developed acute nonoliguric renal failure associated with inhaled tobramycin. Clinical evaluation and renal biopsy findings were consistent with aminoglycoside‐induced changes. Renal failure due to inhaled aminoglycosides has not been previously reported. The incidence may rise, however, with the increased use of this treatment modality. Measurable tobramycin levels due to inhalational therapy with conventional dosing in the reported patient indicate that the drug can be systemically absorbed, and renal tubular toxicity may occur. Pediatr Pulmonol. 2002; 34:375–377. © 2002 Wiley‐Liss, Inc.
Construction and characterization of β‐lactoglobulin chimeras
Authors: Kobayashi Takuji , Ikeguchi Masamichi , Sugai Shintaro
Published: October 2002

At neutral pH, equine β‐lactoglobulin (ELG) is monomeric, whereas bovine β‐lactoglobulin (BLG) exists as a dimer. To understand the difference in the oligomerization properties between ELG and BLG, three mutants of ELG (LP, I, and LPI) were constructed by substituting amino acids responsible for important interactions at the dimer interface of BLG into ELG. The mutant LP has an AB loop mutation (S34A/E35Q), the mutant I has an I strand mutation (G145M/R146H/V147I/Q148R/I149L/V150S/P151F/D152N/L153P) and the mutant LPI includes both the LP and I mutations. The far‐ and near‐UV CD spectra of the three mutants are similar to that of the wild‐type ELG, indicating that the secondary and the tertiary structures of ELG are not significantly affected by the mutations. Ultracentrifuge analysis shows that all three mutants are monomeric at neutral pH, suggesting that the protein sequences in the AB loop and I strand of BLG alone cannot support dimerization of ELG. Thus, structural differences must exist between ELG and BLG that prevent the ELG mutants from forming the same interactions as BLG at the dimer interface. Proteins 2002;49:297–301. © 2002 Wiley‐Liss, Inc.
Activation of octopaminergic receptors by essential oil constituents isolated from aromatic plants: possible mode of action against insect pests
Authors: Kostyukovsky Moshe , Rafaeli Ada , Gileadi Carina , Demchenko Nataly , Shaaya Eli
Published: October 2002

As a result of screening a large number of essential oils from Israeli aromatic plants and their biologically active constituents, we isolated two oils with high activity against several stored‐product insects. In this study the effect of these compounds on the acetylcholinesterase and the octopamine systems in insects was studied in order to elucidate their mode of action. Inhibition of acetylcholinesterase activity in vitro was evident only at high concentrations (10−3 M) and could not account effectively for the low‐dose mortality for some stored‐product insects observed in vivo. However, the essential oil constituents were found to cause a significant increase in the levels of the intracellular messenger, cyclic AMP of abdominal epidermal tissue in the model insect, Helicoverpa armigera Hübn. The effect was significant even at low, physiological concentrations (10−8 M) when tested directly on abdominal epidermal tissue preparations in vitro. This intracellular response was found to resemble closely the significant increases in the levels of the cyclic AMP of abdominal epidermal tissue due to treatment with the neurotransmitter/neuromodulator, octopamine. Subsequent treatment with the octopaminergic antagonist, phentolamine, effectively inhibited the cyclic AMP levels induced by essential oil treatment, indicating possible competitive activation of octopaminergic receptors by essential oil constituents.

© 2002 Society of Chemical Industry
Production of patchouli mild mosaic virus resistant patchouli plants by genetic engineering of coat protein precursor gene
Authors: Kadotani Naoto , Ikegami Masato
Published: October 2002

Patchouli (Pogostemon cablin (Blanco) Benth), an aromatic crop which yields an essential oil, is widely cultivated in South‐east Asia. Patchouli mild mosaic virus (PaMMV) infects patchouli plants and causes decrease in leaf biomass and essential oil yield. Transgenic patchouli plants with PaMMV coat protein precursor (CP‐P) gene have been produced by Agrobacterium‐mediated transformation. PaMMV CP‐P gene integration into the patchouli genome was confirmed by the PCR method and by Southern blot analysis. The transformants were estimated to contain one to three copy genes using Southern blot analysis. The transformant with three copy genes was tested for the resistance to PaMMV by artificially inoculating plants grown in an environmentally controlled cabinet, and this transformant was found to be highly resistant to PaMMV. The transgenic patchouli plant with PaMMV CP‐P gene should provide valuable material for protecting against PaMMV.

© 2002 Society of Chemical Industry
Antiinflammatory investigation of some species of Mikania
Authors: Suyenaga E. S. , Reche E. , Farias F. M. , Schapoval E. E. S. , Chaves C. G. M. , Henriques A. T.
Published: October 2002

Mikania laevigata Schultz Bip. ex Baker, M. involucrata Hook. et Arn. and M. hirsutissima DC. (Asteraceae), commonly occurring in the southern Brazilian State of Rio Grande do Sul, were submitted to biological tests to evaluate their potential antiinflammatory activity. Decoctions from the leaves and stems were analysed by the induced rat paw oedema and pleurisy models. The animals were treated orally with different decoction doses. In the induced rat paw oedema test, the animals treated with leaf decoctions from M. laevigata (200 mg/ kg) and M. involucrata (50 mg/ kg) presented an oedema inhibition of 81.56% and 81.67%, respectively, 3 h after the administration of the phlogistic agent. Leaf decoctions from M. hirsutissima (400 mg/ kg) did not show such an activity. Stem decoctions displayed lower antiinflammatory activity when compared with the same doses and response time of the leaf decoctions for all analysed species. In the pleurisy assay, leaf decoctions from M. laevigata (400 mg/ kg) and M. involucrata (200 mg/ kg) inhibited leukocyte migration to the pleural exudate by 28.26% and 54.35%, respectively. Copyright © 2002 John Wiley & Sons, Ltd.
Antioxidative components of Psoralea corylifolia (Leguminosae)
Authors: Haraguchi Hiroyuki , Inoue Junji , Tamura Yukiyoshi , Mizutani Kenji
Published: October 2002

A meroterpene and four flavonoids were isolated from the seeds of Psoralea corylifolia as antioxidative components. Their structures were elucidated by spectral data and identified as bakuchiol (1), bavachinin (2), bavachin (3), isobavachin (4) and isobavachalcone (5). In particular, meroterpene 1 and flavonoids 4 and 5 showed broad antioxidative activities in rat liver microsomes and mitochondria. They inhibited NADPH‐, ascorbate‐, t‐BuOOH‐ and CCl4‐induced lipid peroxidation in microsomes. They also prevented NADH‐dependent and ascorbate‐induced mitochondrial lipid peroxidation. Bakuchiol (1) was the most potent antioxidant in microsomes and the inhibition of oxygen consumption induced by lipid peroxidation was time‐dependent. Furthermore, bakuchiol (1) protected human red blood cells against oxidative haemolysis. These phenolic compounds in P. corylifolia were shown to be effective in protecting biological membranes against various oxidative stresses. Copyright © 2002 John Wiley & Sons, Ltd.
Modulation of serum phosphatases activity in Swiss albino mice against gamma irradiation by Mentha piperita Linn.
Authors: Samarth R. M. , Goyal P. K. , Kumar Ashok
Published: October 2002

The modulatory influence of mentha oil (Mentha piperita Linn.) against a lethal dose (8.0 Gy) of gamma irradiation on the activities of serum phosphatases in Swiss albino mice was studied at various post‐irradiation intervals between 6 h and 30 days. Mentha oil (40 μL/animal/day) given orally for 3 consecutive days prior to whole‐body irradiation (8.0 Gy) showed a modulation of activity of serum phosphatases. The values of acid phosphatase activities were significantly higher in the irradiated groups throughout the experiment compared with the mentha treated unirradiated animals. However, the acid phosphatase activity of mentha treated irradiated animals showed a significant decline over untreated irradiated animals at all autopsy intervals, which attained the normal value on day 5. On the contrary, a marked decrease in serum alkaline phosphatase activity was noted in both irradiated groups but in the mentha treated irradiated group the values of alkaline phosphatase activity were found to be significantly higher than the respective control during the period of study being normal at day 5 post‐irradiation and onwards. Copyright © 2002 John Wiley & Sons, Ltd.
Bioactive phenolic derivatives from Acaena splendens methanol extract
Authors: Backhouse N. , Delporte C. , Negrete R. , Feliciano S. A. San , López‐Pérez J. L.
Published: October 2002

Acaena splendens H. et A. has been used in Chilean folk medicine for the treatment of fever and inflammation. A description of the in vivo reduction of bacterial pyrogen‐induced fever in rabbits and carrageenan‐induced paw oedema in guinea pigs is presented. The methanol extract named ME‐1, obtained after succesive extractions with petroleum ether and dichloromethane, showed a strong antipyretic action (45.7% of effect), though the antiinflammatory activity was only observed after submitting this extract to column fractionation, giving a crude mixture of flavonoids named C4 with both activities (55.7% and 98.9% of antiinflammatory and antipyretic effect respectively at a dose of 600 mg/kg). The bioassay‐guided fractionation by column chromatography afforded the active fraction, which contained (‐,‐)‐epicatechin, tiliroside, 7‐O‐acetyl‐3‐O‐β‐D‐glucosyl‐kaempferol and 7‐β‐D‐glucosyloxy‐5‐hydroxy‐chromone. Copyright © 2002 John Wiley & Sons, Ltd.
Thomas–Fermi theory revisited
Authors: Nesbet R. K.
Published: October 2002

An exact Thomas–Fermi theory requires the existence of a Fréchet functional derivative of the Hohenberg–Kohn universal functional. Although, as recently shown, such a functional derivative cannot exist in quantum theory for more than two electrons, functional derivatives of the more general type defined by Gâteaux do exist. When the theory is reformulated in terms of Gâteaux derivatives, for noninteracting electrons, it is equivalent to the Schrödinger theory. For interacting electrons, it defines a generalized orbital‐functional theory. The reformulated theory incorporates Fermi–Dirac statistics for electrons and deals correctly with atomic shell structure. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 90: 262–265, 2002
On canonical perturbation theory in classical mechanics
Authors: Fernández Francisco M.
Published: October 2002

We develop canonical perturbation theory for classical mechanics by means of the Lie method in a simple way that does not require the use of complex variables to solve the perturbation equations. In order to illustrate the approach we apply it to anharmonic oscillators. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Model study of the impact of orbital choice on the accuracy of coupled‐cluster energies. IV. Single‐reference‐state methods in applications to excited states*
Authors: Jankowski K. , Rubiniec K.
Published: October 2002

Model studies of the impact of the choice of the molecular orbital sets defining the reference determinant on the results of single‐reference‐state coupled‐cluster (SR–CC) methods for excited states of a predominately closed‐shell structure were performed for the first time. We have used the H4 model, which offers an easy way of representing any set of symmetry‐adapted orbitals as well as the possibility of varying the degree of quasi‐degeneracy of the states considered. The CCD, CCSD, and CCSDT methods (D, S, T denote that doubly‐, singly‐, triply‐excited configurations, respectively, are accounted for) are applied in calculations for several excited states disclosing rather strong quasi‐degeneracy. Orbital sets representing multiple solutions to the restricted Hartree–Fock (RHF) equations and nonstandard orbitals defined by nodes of a two‐dimensional orbital grid have been used to define the reference determinant. Attention is paid to documenting and discussing similarities and differences for excited states and the ground state in the characteristic of SR–CC approaches. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Comparison of lithium and hydrogen bonds in (X···Li···X)− and (X···H···X)− (XF, Cl and Br) complexes: Topological analysis of electron localization function
Authors: Berski Sławomir , Latajka Zdzisław
Published: October 2002

The topological analysis of the electron localization function (ELF) is used to elucidate the nature of the hydrogen and lithium bonds in the (X···Y···X)− (XF, Cl, Br; YH, Li) complexes. The lithium bond that exhibits an electrostatic nature is characterized by a constant mean electron population of the lithium core basin C(Li) equal to 2.03e. The values of the ELF within Li···X regions are smaller than 0.5 corresponding to a totally delocalized electron density. For the X···H hydrogen bonds a covalent nature is found with an essential electron pairing, as implied by values of ELF in the H···X regions larger than 0.5. The mean electron population of the V(H) basin depends on electronegativity of a halogen atom, and it ranges from 0.17e for (F···H···F)− to 2.11e for (Br···H···Br)−. The polarization of halogen anions X− by lithium or hydrogen cations results in an anisotropy of the nonbonding electron density, which is reflected by two valence attractors V1(Xi=1,2) and V2(Xi=1,2) found inside and outside a complex, respectively. The analysis of the H···Br hydrogen bond reveals essential differences as compared with the H···X (XF and Cl) hydrogen bonds. The topology of nonbonding electrons of Br yields only one valence, monosynaptic basin V(Bri=1,2). Furthermore, similarity of the H···Br hydrogen bonds to a bond in an isolated HBr molecule is noted. The increased Pauli repulsion between the V(H) and V1(Xi=1,2) basins in the (X···H···X)− complexes leads to a larger electron delocalization of V1(Xi=1,2) as compared with the (X···Li···X)− systems. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Matrix isolation and DFT studies of nitrous acid complexes with nitrogen dioxide
Authors: Olbert‐Majkut Adriana , Mielke Zofia , Wieczorek Robert , Latajka Zdzisław
Published: October 2002

Complexes between trans or cis isomers of nitrous acid and nitrogen dioxide have been isolated in argon matrices and studied using Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT) calculation at B3LYP level with the 6‐311++G(2d,2p) basis set. Six perturbed vibrations of trans‐HONO and three perturbed vibrations of cis‐HONO isomers were identified for the trans and cis‐HONO complexes, respectively. The perturbed asymmetric stretching vibration of NO2 molecule was also identified for the two complexes. The experimental spectra suggest and the theoretical calculations confirm that there is double interaction in the two complexes. The OH group of HONO molecule serves as a proton donor to an oxygen atom of NO2, and in addition to hydrogen bonding there is an electrostatic attraction between an oxygen atom of OH and nitrogen atom of NO2 molecules. Calculated counterpoise corrected interaction energy is equal to −1.19 and −1.10 kcal/mol for NO2…cis‐HONO and NO2…trans‐HONO complexes, respectively. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002