bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytical characterisation of crude extracts from an african Ancistrocladus species using high‐performance liquid chromatography and capillary electrophoresis coupled to ion trap mass spectrometry
Authors: Unger Matthias , Dreyer Michael , Specker Sven , Laug Stefanie , Pelzing Matthias , Neusüß Christian , Holzgrabe Ulrike , Bringmann Gerhard
Published: January 2004

The analysis by HPLC, CE and CE‐MS/MS of root bark extracts of a, so far undescribed, Central‐African Ancistrocladus species (family Ancistrocladaceae) is described. Owing to the complexity of the extract, the application of reversed‐phase HPLC resulted in a partially incomplete separation of the naphthylisoquinoline alkaloids, whilst CE using a non‐aqueous buffer proved to be a very valuable complementary method for a ﬁrst characterisation of the crude extract. By performing additional CE‐MS/MS experiments, in combination with parallel isolation studies and structural elucidation using conventional methods, six alkaloidal substances present in the plant could be identiﬁed. Copyright © 2004 John Wiley & Sons, Ltd.
Determination of colchicine in Colchicum steveni and C. hierosolymitanum (colchicaceae): comparison between two analytical methods
Authors: Alali Feras , Tawaha Khaled , Qasaymeh Rana M.
Published: January 2004

The amounts of colchicine present in two Jordanian species of Colchicum, namely, C. steveni Kunth and C. hierosolymitanum Feibrun (Colchicaceae), have been determined. An HPLC‐UV (photodiode array) method employing gradient elution was developed and the results compared with those obtained using a simple TLC‐spectrophotometric method. The levels of colchicine as measured by these methods were not signiﬁcantly different (p < 0.05) indicating that the spectrophotometric method is an acceptable alternative to HPLC. With respect to C. steveni, the leaves contained the largest amount of colchicine (0.204/100 g), whilst in C. hierosolymitanum corms showed the highest colchicine content (0.126/100 g). As a source of colchicine, the two investigated species showed levels comparable with those found in C. autumnale, the traditional source of colchicine. Copyright © 2004 John Wiley & Sons, Ltd.
Simultaneous quantitative determination of eight triterpenoid monoesters from flowers of 10 varieties of Calendula ofﬁcinalis L. and characterisation of a new triterpenoid monoester
Authors: Neukirch Hannes , D'Ambrosio Michele , Via Josef Dalla , Guerriero Antonio
Published: January 2004

Dichloromethane extracts of dried ﬂowers of Calendula ofﬁcinalis contain eight known bioactive triterpendiol monoesters, namely, faradiol‐3‐O‐palmitate, faradiol‐3‐O‐myristate, faradiol‐3‐O‐laurate, arnidiol‐3‐O‐palmitate, arnidiol‐3‐O‐myristate, arnidiol‐3‐O‐laurate, calenduladiol‐3‐O‐palmitate and calenduladiol‐3‐O‐myristate. These pentacyclic terpenoids have been quantiﬁed simultaneously using reversed‐phase HPLC with isocratic elution and internal standardisation. Of the 10 varieties of C. ofﬁcinalis investigated, Calypso Orange Florensis produced the highest amounts of the bioactive monoesters, followed by Fiesta Gitana Gelb and May Orange Florensis. The lipophilic extract from the ﬂowers of Calypso Orange Florensis variety also contained low levels of the newly characterised calenduladiol‐3‐O‐laurate. Copyright © 2004 John Wiley & Sons, Ltd.
Identiﬁcation and quantiﬁcation of components in extracts of Uncaria tomentosa by HPLC‐ES/MS
Authors: Montoro P. , Carbone V. , de Dioz Zuniga Quiroz J. , De Simone F. , Pizza C.
Published: January 2004

The two main classes of secondary metabolites, alkaloids and quinovic acid glycosides, of Uncaria tomentosa (Willd.) DC. (Rubiaceae), a Peruvian plant commonly known as ‘uña de gato’, have been analysed. Separation of the alkaloidal fraction was achieved using a solid phase extraction method based on cationic exchange, and an analytical method employing HPLC‐ES/MS has been developed. Quantitative data for commercial wild bark, cultivated bark and leaves are reported. The analysis of quinovic acid glycosides was performed directly on the crude extract using both a fast analytical method based on ﬂow injection ES/MS, and a more complete analytical technique using HPLC‐MS. Copyright © 2004 John Wiley & Sons, Ltd.
Screening for oestrogenic activity of plant and food extracts using in vitro trout hepatocyte cultures
Authors: Bennetau‐Pelissero C. , Gontier Latonnelle K. , Lamothe V. , Shinkaruk‐Poix S. , Kaushik S. J.
Published: January 2004

The use of in vitro trout hepatocyte cultures is shown to provide a simple and effective way to screen plant and food products for oestrogenic activity. The relative oestrogenic activities of 0.1 g each of extracts of phytosterol, soy isoﬂavone, red clover, kudzu and soybean extracts were determined using this assay and found to be equivalent to 212, 1, 3.2, 132 and 1025 nm of 17β‐estradiol, respectively. Controls were performed on soybean and kudzu extracts using speciﬁc ELISAs for isoﬂavones and these conﬁrmed the validity of the cell culture assay. The method described offers an advantage over current methods in that it can detect increased oestrogenic activity that may occur as a result of metabolic activation of pre‐ or pro‐oestrogens liver cells. Copyright © 2004 John Wiley & Sons, Ltd.
Supercritical carbon dioxide extraction of selected medicinal plants—effects of high pressure and added ethanol on yield of extracted substances
Authors: Hamburger M. , Baumann D. , Adler S.
Published: January 2004

The possibilities and limitations of supercritical ﬂuid extraction of natural products of low, medium and high polarity under very high pressure and with polar modiﬁers has been investigated. The medicinal herbs marigold (Calendula ofﬁcinalis), hawthorn (Crataegus sp.) and chamomile (Matricaria recutita) were used as models in this study. Extraction proﬁles and the spectra of extractable metabolites were recorded following extraction with mixtures of carbon dioxide:ethanol of varying proportions (0–20% ethanol) and at various pressures in the range 300–689 bar. Components were identiﬁed by HPLC‐PAD‐MS or GC‐MS and quantiﬁed by HPLC or GC as appropriate. Extraction yields under the varying conditions depended to a large extent on the proﬁles of secondary metabolites present in the three drugs. Whereas the extractability of lipophilic compounds increased substantially at pressures above 300 bar, the yields of polyphenolic and glycosidic compounds remained low even at 689 bar and with 20% modiﬁer in the extraction ﬂuid. Copyright © 2004 John Wiley & Sons, Ltd.
Validation of a capillary electrophoresis method for the quantitative determination of free and total apigenin in extracts of Chamomilla recutita
Authors: Fonseca Fabiana N. , Tavares Marina F. M.
Published: January 2004

A capillary electrophoretic method for the quantiﬁcation of free and total apigenin in methanolic, ethanolic and glycolic extracts of Chamomilla recutita L. Rauschert (Asteraceae) is described. The method was validated for measurement of apigenin in the range 5.00–300 µg/mL (r2 = 0.993) and showed coefﬁcients of intra‐day (replicability) and inter‐day (repeatability) variability of better than 2%. The limits of detection and quantiﬁcation were 3.80 and 11.5 µg/mL, respectively, and the average recovery was 102.0 ± 0.8% at three concentration levels of apigenin. Free and total apigenin contents in the extracts were, respectively, determined as 106 and 903 µg/g (methanolic extract), 77 and 817 µg/g (ethanolic extract) and 11.0 and 247 µg/g (glycolic extract). Copyright © 2004 John Wiley & Sons, Ltd.
Radiographic and genetic diagnosis of sporadic hypochondroplasia early in the neonatal period
Authors: Kataoka Soromon , Sawai Hideaki , Yamada Hideto , Kanazawa Nozomi , Koyama Koji , Nishimura Gen , Morikawa Mamoru , Sakuragi Noriaki , Minakami Hisanori
Published: January 2004

Hypochondroplasia is an autosomal dominant skeletal dysplasia expressing postnatal onset of short stature with mild rhizomelic shortening of the limbs. This manifestation leads to restricted prenatal diagnosis of the disorder. We report here on a sporadic case of a hypochondroplastic baby, whose prenatal sonographic measurements were serially recorded from 19 weeks of gestation. Mild shortening of the limbs became manifest after 26 weeks of gestation. Biparietal diameter was within the normal range throughout gestation. Both parents were of average stature. A tentative diagnosis of a nonlethal short‐limb skeletal dysplasia was made. At birth, the clinical manifestations of the neonate were not characteristic, but the radiographic features raised the possibility of hypochondroplasia. Molecular analyses revealed a C to G mutation at nucleotide 1659 of the fibroblast growth factor receptor 3 (FGFR3) gene, a common mutation in hypochondroplasia. Copyright © 2004 John Wiley & Sons, Ltd.
Prenatal sonographic diagnosis of congenital hiatal hernia
Authors: Ruano Rodrigo , Benachi Alexandra , Aubry Marie‐Cecile , Bernard Jean‐Pierre , Hameury Fréderic , Nihoul‐Fekete Claire , Dumez Yves
Published: January 2004

Objectives

To report a rare case of congenital hiatal hernia illustrating the importance of its prenatal diagnosis as well as to discuss the prenatal sonographic criteria.

Case Report

A case of congenital hiatal hernia was diagnosed by ultrasound at 33 weeks of gestation. After a normal second‐trimester morphologic ultrasound examination, a hypoechogenic mass was detected in the posterior mediastinum juxtaposed to the vertebral body and seemed to be in continuity with the intra‐abdominal stomach bubble. Congenital hiatal hernia was suspected mainly because of the dynamic position of the stomach during the examination, without mediastinal shift, and normal appearance of the diaphragm on parasagittal sections of the thorax. Postnatal management was planned with no urgency and surgery was successfully performed, confirming the diagnosis.

Conclusion

This rare case illustrates the importance of prenatal diagnosis of congenital hiatal hernia for prenatal counseling and postnatal management. The ultrasound criterion for prenatal diagnosis is the presence of a herniated stomach in the posterior mediastinum, sometimes having a dynamic position during examination, with no mediastinal shift associated with normal diaphragm appearance on parasagittal sections of the thorax. Copyright © 2003 John Wiley & Sons, Ltd.
Prenatal diagnosis of mosaic distal 5p deletion and review of the literature
Authors: Chen Chih‐Ping , Lee Chen‐Chi , Chang Tung‐Yao , Town Dai‐Dyi , Wang Wayseen
Published: January 2004

Objectives

To present the prenatal diagnosis of mosaic distal 5p deletion and a review of the literature.

Clinical subject and methods

A 37‐year‐old woman, gravida 2, para 1, underwent genetic amniocentesis at 17 weeks' gestation because of advanced maternal age. Cytogenetic analysis of the cultured amniocytes revealed mosaicism for a distal 5p deletion, mos 46,XX,del(5)(p15.1)/46,XX (23 colonies/23 colonies). Repeat amniocentesis showed a consistent karyotype of mos 46,XX,del(5)(p15.1)/46,XX (12 colonies/15 colonies). The parental karyotypes were normal. Prenatal ultrasound demonstrated microcephaly and cerebellar hypoplasia. The pregnancy was terminated at 21 weeks' gestation. Postnatally, the fetus displayed microcephaly, a triangular face, hypertelorism, epicanthic folds, down‐slanting palpebral fissures, low‐set ears, and micrognathia. A karyotype of mos 46,XX,del(5)(p15.1)/46,XX was found in the cord blood, liver, lungs, and skin, whereas the placenta had a different karyotype of mos 46,XX,dup(5)(qter→p15.3::p15.3→p10)/46,XX, and the karyotype of the amnion was mos 46,XX,del(5)(p15.1)/46,XX,dup(5)(qter→p15.3::p15.3→p10)/46,XX,trp(5)(qter→p15.3::p15.3→p10::p10→p15.3)/46,XX. The deletion, duplication, and triplication of the terminal region of the short arm of chromosome 5 were confirmed by the studies of fluorescence in situ hybridization.

Conclusion

The cri‐du‐chat syndrome can be identified prenatally because of advanced maternal age, familial cri‐du‐chat syndrome, parental balanced translocations involving chromosome 5, sonographically detected fetal structural abnormalities, and/or an abnormal maternal serum test. Fetuses with the mosaic distal 5p deletion may be associated with the sonographic findings of microcephaly and cerebellar hypoplasia, and fetoplacental and fetoamnionic chromosomal discrepancies. Copyright © 2004 John Wiley & Sons, Ltd.
Crystallization kinetics of poly(ethylene oxide) from its melt and from mixtures with tetrahydronaphthalene and oligo(ethylene oxide‐block‐dimethylsiloxane)
Authors: Madbouly Samy A. , Wolf Bernhard A.
Published: January 2004

The crystallization of poly(ethylene oxide) (PEO) from the pure state and from its mixtures with oligo(dimethyl siloxane‐b‐ethylene oxide) (COP) and tetrahydronaphthalene (THN) was investigated. The crystallization kinetics was studied isothermally and nonisothermally with an automated device that monitored the light passing through the corresponding liquids as functions of time and/or temperature. The rate was strongly influenced by the concentration of COP in the mixture. A substantial decrease in the induction time (the time required for the onset of crystallization) and a considerable shift in the crystallization temperature (the transition from a liquid state to a solid state) to higher temperatures were observed as the concentration of COP rose. This behavior was attributed to the differences in the interaction parameters of PEO with THN and COP. The isothermal crystallization kinetics was analyzed on the basis of the Avrami equation. Modified approaches (Avrami and Ozawa) were used for the evaluation of nonisothermal crystallization. In the initial state of crystallization, a power law held true for the augmentation of the radii of spherulites with time for all mixtures, regardless of the concentration of COP. Different spherulitic morphologies were observed, depending on the COP concentration. With rising COP contents, the structures changed from being needlelike to being compact. These findings were all examined in terms of the isothermal variation of the degree of supercooling resulting from changes in the compositions of the mixtures. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 820–829, 2004
Thermally induced color change in electrospun fiber mats
Authors: Pedicini Angelo , Farris Richard J.
Published: January 2004

Electrospinning is a process that employs a high static electrical potential to produce polymeric fibers of nanoscale diameter. The process has been utilized to achieve color change by electrospinning black polymer solutions to produce white fiber mats. When subsequently heated, the electrospun mats undergo a color change from white to black. This phenomenon is demonstrated with three polymer/solvent systems. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 752–757, 2004
Effects of added surfactants on thermoreversible gelation of associating polymer solutions
Authors: Furuya Tsutomu , Koga Tsuyoshi , Tanaka Fumihiko
Published: January 2004

The influence of added surfactants on physical properties of associating polymer solutions was examined by a new statistical‐mechanical theory of associating polymer solutions with multiple junctions and by computer simulation. The sol–gel transition line, the spinodal line, and the number of elastically effective chains in the mixed networks were calculated as functions of the concentration of added surfactants. All of them exhibited nonmonotonic behavior as a result of the following two competing mechanisms. One was the formation of new mixed micelles by binding surfactants onto the polymer associative groups. These micelles serve as crosslink junctions and promote gelation. The other was the replacement of polymer associative groups in the already formed network junctions by added surfactants. Such replacement lowers connectivity of junctions and destroys networks. The critical micelle concentration was also calculated. The results are compared with the reported experimental data on poly(ethylene oxide)‐based associating polymers and hydrophobically modified cellulose derivatives. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 733–751, 2004
The effect of compatibilization and rheological properties of polystyrene and poly(dimethylsiloxane) on phase structure of polystyrene/poly(dimethylsiloxane) blends
Authors: Chuai C. Z. , Li S. , Almdal K. , Alstrup J. , Lyngaae‐Jørgensen J.
Published: January 2004

The compatibilization effect of polystyrene (PS)‐poly(dimethylsiloxane) (PDMS) diblock copolymer (PS‐b‐PDMS) and the effect of rheological properties of PS and PDMS on phase structure of PS/PDMS blends were investigated using a selective extraction technique and scanning electron microscopy (SEM). The dual‐phase continuity of PS/PDMS blends takes place in a wide composition range. The formation and the onset of a cocontinuous phase structure largely depend on blend composition, viscosity ratio of the constituent components, and addition of diblock copolymers. The width of the concentration region of the cocontinuous structure is narrowed with increasing the viscosity ratio of the blends and in the presence of the small amount diblock copolymers. Quiescent annealing shifts the onset values of continuity. The experimental results are compared with the volume fraction of phase inversion calculated with various theoretical models, but none of the models can account quantitatively for the observed data. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 898–913, 2004
Effect of structure on properties of polyols and polyurethanes based on different vegetable oils
Authors: Zlatanić Alisa , Lava Charlene , Zhang Wei , Petrović Zoran S.
Published: January 2004

We synthesized six polyurethane networks from 4,4′‐diphenylmethane diisocyanate and polyols based on midoleic sunflower, canola, soybean, sunflower, corn, and linseed oils. The differences in network structures reflected differences in the composition of fatty acids and number of functional groups in vegetable oils and resulting polyols. The number average molecular weights of polyols were between 1120 and 1300 and the functionality varied from 3.0 for the midoleic sunflower polyol to 5.2 for the linseed polyol. The functionality of the other four polyols was around 3.5. Canola, corn, soybean, and sunflower oils gave polyurethane resins of similar crosslinking density and similar glass transitions and mechanical properties despite somewhat different distribution of fatty acids. Linseed oil–based polyurethane had higher crosslinking density and higher mechanical properties, whereas midoleic sunflower oil gave softer polyurethanes characterized by lower Tg and lower strength but higher elongation at break. It appears that the differences in properties of polyurethane networks resulted primarily from different crosslinking densities and less from the position of reactive sites in the fatty acids. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 809–819, 2004
Thermomechanical properties of liquid‐crystalline epoxy networks arranged by a magnetic field
Authors: Harada Miyuki , Ochi Mitsukazu , Tobita Masayuki , Kimura Tohru , Ishigaki Tsukasa , Shimoyama Naoyuki , Aoki Hisashi
Published: January 2004

During the curing process of a liquid‐crystalline epoxy resin, a relatively strong magnetic field was applied, and the thermomechanical properties of the cured resin were investigated. The network orientation and mechanical properties of the cured system were evaluated with wide‐angle X‐ray diffraction, dynamic mechanical analysis, and fracture toughness testing. The cured system was found to have an anisotropic network structure, which arranged along the applied field, and the anisotropy was reflected in the thermomechanical properties. In particular, the fracture toughness of the system dramatically increased when the network chains were arranged across the direction of the crack propagation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 758–765, 2004
Phase separation of off‐critical polymer blends of poly(styrene‐co‐maleic anhydride) and poly(methyl methacrylate). I. Kinetics of spinodal decomposition
Authors: Rojanapitayakorn Pichet , Thongyai Supakanok , Covavisaruch Sirijutaratana
Published: January 2004

The kinetics of phase separation via the spinodal decomposition of poly(styrene‐co‐maleic anhydride)/poly(methyl methacrylate) from a delay time period to late stages were investigated with a light scattering technique. The standard procedure for identifying four stages of spinodal decomposition, based on the characteristics of concentration fluctuations, was clearly introduced with the light scattering method. The spinodal limits were divided into four stages: the delay time, the early stage, the intermediate stage, and the late stage. The validity of the linearized theory was reviewed because it was used as an indicator of the limit of the early stage of spinodal decomposition, which divided the delay time period from the early stage and the early stage from the intermediate stage. The linearized theory fit the experimental results very well after the delay time. The scaled structure function of the melt‐mixed blend was analyzed. The universality of the scale structure function, F(x) = S(q,t)qm3(t) (where S is the structure function, x is equal to q/qm, q is the scattering wave vector, qm is the maximum wave vector, and t is the time in seconds), indicated the late stage of phase separation and divided the late stage from the intermediate stage. The simple normalized scaling function profile for the cluster region proposed by Furukawa described the experimental data very well, whereas the profile for deep quenching, which was recently suggested, showed some discrepancies. As a result of the phase separation, the processing of this blend may be able to be developed to provide the most suitable morphology. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 871–885, 2004
Phase separation of off‐critical polymer blends of poly(styrene‐co‐maleic anhydride) and poly(methyl methacrylate). II. Morphology and mechanical properties
Authors: Rojanapitayakorn Pichet , Thongyai Supakanok , Covavisaruch Sirijutaratana
Published: January 2004

The effects of the phase‐separation temperature and time on the mechanical properties and morphology of poly(methyl methacrylate)/poly(styrene‐co‐maleic anhydride with 10 wt% ethyl acrylate) (SMA) blends were studied. Two compositions (20/80 and 40/60 w/w SMA/PMMAe) were prepared with a miniature twin‐screw extruder. Compared with those of the miscible blends, the Young's modulus values of the blends increased after the phase separation of the 40/60 SMA/PMMAe blend and within the early stage of spinodal decomposition of the 20/80 SMA/PMMAe blend. The mechanical properties, in terms of the tensile strength at break and the elongation, were better for the miscible blends than for the phase‐separation blends. This was believed to be the result of changes in the composition and molecular reorganization. The changes in the phase‐separating domains of both compositions, as observed by transmission electron microscopy, had no significant influence on the tensile moduli. Detailed studies of the morphology revealed a cocontinuous structure, indicating that the blends underwent spinodal decomposition. A morphological comparison of the two compositions illustrated the validity of the level rule. The growth rate of the droplet size was determined by approximation from the light scattering data and by direct measurements with transmission electron microscopy. The discrepancies observed in the droplet size growth rate were attributed to heat variations induced by the different sample thicknesses and heat transfer during the investigation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 886–897, 2004
Gelation in strongly charged polyelectrolytes
Authors: Ermoshkin A. V. , Olvera De La Cruz M.
Published: January 2004

Crosslinking of strongly charged chains via multivalent ions of valence z was treated within the Flory approach, which accounts only for the treelike architecture of the clusters formed. Density–density correlations due to the electrostatic nature of the system were considered with a modified random‐phase approximation. At a certain concentration of multivalent ions that play the role of effective stickers among z monomers, an infinitely large polymer network was formed. We analyzed the gelation driven by the formation of locally neutral clusters induced by divalent and trivalent ions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 766–776, 2004
Effect of silver nanoparticles on the dynamic crystallization behavior of nylon‐6
Authors: Chae Dong Wook , Oh Seong Geun , Kim Byoung Chul
Published: January 2004

The effect of introducing silver nanoparticles on the rheological properties and dynamic crystallization behavior of nylon‐6 was investigated. The nanocomposites showed slightly higher viscosity than pure nylon‐6 in the low‐frequency range even at an extremely low loading level of the silver particles (0.5–1.0 wt %). The nanoparticles had a more noticeable effect on the storage modulus than on the loss modulus of a nylon‐6 melt and reduced its loss tangent. They increased the crystallization temperature of nylon‐6 by about 14 °C and produced a sharper crystalline peak. The silver nanoparticles promoted the crystallization of nylon‐6, and their effect on the dynamic crystallization of nylon‐6 at 200 °C was more notable at a lower shear rate and at 190 °C at a higher frequency. Nylon‐6 produced large spherulitic crystals, but the nanocomposites showed a grainy structure. In addition, the silver nanoparticles reduced the fraction of the α‐form crystal but increased that of the γ‐form crystal. The nanocomposites crystallized at 190 °C showed a lower melting temperature than nylon‐6 by about 3 °C, whereas the nanocomposites crystallized at 200 °C showed almost the same melting temperature. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 790–799, 2004
Molecular relaxation of isotactic polystyrene: Real‐time dielectric spectroscopy and X‐ray scattering studies*
Authors: Natesan Baskaran , Xu Hui , Seyhan Ince B. , Cebe Peggy
Published: January 2004

The molecular relaxation processes and structure of isotactic polystyrene (iPS) films were investigated with real‐time dielectric spectroscopy and simultaneous wide‐ and small‐angle X‐ray scattering. The purpose of this work was to explore the restrictions imposed on molecular mobility in the vicinity of the α relaxation (glass transition) for crystallized iPS. Isothermal cold crystallization at temperatures of Tc = 140 or 170 °C resulted in a sigmoidal increase of crystallinity with crystallization time. The glass‐transition temperature (Tg), determined calorimetrically, exhibited almost no increase during the first stage of crystal growth before impingement of spherulites. After impingement, the calorimetric Tg increased, suggesting that confinement effects occur in the latter stages of crystallization. For well‐crystallized samples, the radius of the cooperativity region decreased substantially as compared with the purely amorphous sample but was always smaller than the layer thickness of the mobile amorphous fraction. Dielectric experiments directly probed changes in the amorphous dipole mobility. The real‐time dielectric data were fitted to a Havriliak–Negami model, and the time dependence of the parameters describing the distribution of relaxation times and dielectric strength was obtained. The central dipolar relaxation time showed little variation before spherulite impingement but increased sharply during the second stage of crystal growth as confinement occurred. Vogel–Fulcher–Tammann analysis demonstrated that the dielectric reference temperature, corresponding to the onset of calorimetric Tg, did not vary for well‐crystallized samples. This observation agreed with a model in which constraints affect primarily the modes having longer relaxation times and thus broaden the glass‐transition relaxation process on the higher temperature side. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 777–789, 2004
Viscoelastic behaviors and molecular motions of highly syndiotactic poly(vinyl alcohol) fibers
Authors: Gotoh Yasuo , Nagara Yoshitaka , Nakano Tamaki , Okamoto Yoshio , Ohkoshi Yutaka , Nagura Masanobu
Published: January 2004

The viscoelastic behavior and molecular motion of highly syndiotactic poly(vinyl alcohol) (S‐PVA) fibers with a dyad syndiotacticity (r) of 69% were studied by dynamic mechanical thermal analysis and wide‐angle X‐ray diffraction and compared with those of atactic poly(vinyl alcohol) (A‐PVA) fibers with r = 54%. The βc dispersion, based on the molecular motion of the chain molecules in the crystalline regions, was observed for A‐PVA around 120–140 °C, and the only primary (αc) dispersion was observed for S‐PVA around 180 °C. The thermal expansion coefficients for the a and c axes of the A‐PVA crystal changed discontinuously around 120 °C, which corresponded to the βc dispersion. For S‐PVA, the coefficient for the (002) plane changed discontinuously around 100 °C, similarly to A‐PVA, but that for the (100) plane remained unchanged between 20 and 220 °C. These results showed that the intermolecular hydrogen bonding of S‐PVA was stronger in the direction of the a axis than in the other directions, suppressing the βc dispersion. The storage modulus and thermal expansion coefficient of the (020) plane (molecular axis) of S‐PVA decreased markedly around 180 °C, and this indicated that the αc dispersion was due to the torsional motion of the molecular chains in the crystalline regions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 800–808, 2004
Wide‐angle X‐ray diffraction and differential scanning calorimetry study of the crystallization of poly(ethylene naphthalate), poly(butylene naphthalate), and their copolymers
Authors: Papageorgiou George Z. , Karayannidis George P. , Bikiaris Dimitris N. , Stergiou Anagnostis , Litsardakis George , Makridis Sofoklis S.
Published: January 2004

The crystallization behavior of a series of poly(ethylene‐co‐butylene naphthalate) (PEBN) random copolymers was studied. Wide‐angle X‐ray diffraction (WAXD) patterns showed that the crystallization of these copolymers could occur over the entire range of compositions. This resulted in the formation of poly(ethylene naphthalate) or poly(butylene naphthalate) crystals, depending on the composition of the copolymers. Sharp diffraction peaks were observed, except for 50/50 PEBN. Eutectic behavior was also observed. This showed isodimorphic cocrystallization of the PEBN copolymers. The variation of the enthalpy of fusion of the copolymers with the composition was estimated. The isothermal and nonisothermal crystallization kinetics were studied. The crystallization rates were found to decrease as the comonomer unit content increased. The tensile properties were also measured and were found to decrease as the butylene naphthalate content of the copolymers increased. For initially amorphous specimens, orientation was proved by WAXD patterns after drawing, but no crystalline reflections were observed. However, the fast crystallization of drawn specimens occurred when they were heated above the glass‐transition temperature. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 843–860, 2004
Fine structure of poly(vinylidene fluoride) membranes prepared by phase inversion from a water/N‐methyl‐2‐pyrollidone/poly(vinylidene fluoride) system
Authors: Lin Dar‐Jong , Chang Cheng‐Liang , Chang Chi‐Lin , Chen Tzung‐Chin , Cheng Liao‐Ping
Published: January 2004

Poly(vinylidene fluoride) (PVDF) membranes were prepared by the isothermal immersion and precipitation of PVDF/N‐methyl‐2‐pyrollidone dope solutions in either harsh or soft nonsolvent baths. Low‐voltage field emission scanning electron microscopy imaging of the formed membranes at high magnifications (e.g., 300,000×) revealed their nanoscale fine structures, particularly dendrites observed on the surfaces of the macrovoids, cellular pores, and the membrane skin, which have never been successfully presented in the literature. Evidence of crystallization was also demonstrated by X‐ray diffraction and differential scanning calorimetry measurements. The phase diagram at 25 °C, including a binodal, tie lines, and a crystallization‐induced gelation line, was determined both experimentally and theoretically. These results were further used in mass‐transfer calculations to obtain diffusion trajectories and concentration profiles for the membrane region, which were useful for elucidating the relationship between the membrane preparation conditions and the obtained membrane morphologies. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 830–842, 2004
Nanoindentation studies of polyimide thin films with various internal linkages in the diamine component
Authors: Lee Choonkeun , Kwon Jinuk , Park Sunggook , Sundar Saimani , Min Byoungryul , Han Haksoo
Published: January 2004

Polyimide thin films were synthesized from 3,3′,4,4′‐biphenyltetracarboxylic acid dianhydride (BPDA) and four different diamines (p‐phenylene diamine, 4,4′‐oxydiphenylene diamine, 4,4′‐biphenylene diamine, and 4,4′‐sulfonyldiphenylene diamine). The nanoindentation behavior of the resulting polyimides, namely, poly(p‐phenylene biphenyltetracarboximide) (BPDA‐PDA), poly(4,4′‐biphenylene biphenyltetracarboximide) (BPDA‐BZ), poly(4,4′‐oxydiphenylene biphenyltetracarboximide) (BPDA‐ODA), and poly(4,4′‐sulfonyldiphenylene biphenyltetracarboximide) (BPDA‐DDS), were investigated. Also, the morphological properties were characterized with a prism coupler and wide‐angle X‐ray diffraction and were correlated to the nanoindentation studies. The nanoindentation behavior and hardness varied quite significantly, depending on the changes in the chemical and morphological structures. The hardness of the polyimide thin films increased in the following order: BPDA‐DDS < BPDA‐ODA < BPDA‐BZ < BPDA‐PDA. For all the polyimide thin films, except that of BPDA‐BZ, the hardness decreased with an increase in the load. The birefringence, a measure of the molecular in‐plane orientation, increased in the following order: BPDA‐DDS < BPDA‐ODA < BPDA‐PDA < BPDA‐BZ. The X‐ray diffraction studies revealed that the crystallinity of the polyimide thin films varied with the changes in the chemical structure. The studies showed that the indentation response with an applied load and the hardness by nanoindentation for the BPDA‐based polyimides were closely related to the morphological structure. The nanoindentation and birefringence results revealed that the mechanical properties of the polyimide thin films were dependent on the crystallinity, which arose because of the chain order along the chain axis and the molecular packing order. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 861–870, 2004
Effect of the water state on the electrical bending behavior of chitosan/poly(diallyldimethylammonium chloride) hydrogels in NaCl solutions
Authors: Kim Seon Jeong , Yoon Seoung Gil , Kim Sun I.
Published: January 2004

Semi‐interpenetrating polymer network (SIPN) hydrogels, composed of chitosan (CS) and poly(diallyldimethylammonium chloride) (PDADMAC), were prepared, and they exhibited electrically sensitive behavior. The swelling behavior of the CS/PDADMAC SIPN hydrogels was studied through the immersion of the gels in various concentrations of aqueous NaCl solutions, and their responses to stimuli in electric fields were also investigated. When the swollen SIPN hydrogels were placed between a pair of electrodes, they exhibited bending behavior upon the application of an electric field, which was stepwise and dependent on the magnitude of the field. To clarify the relationship between the equilibrium‐swelling ratio and the bending behavior of the SIPN hydrogels, the state of water in the SIPN hydrogels was also investigated with differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 914–921, 2004
Optical investigation of GaAs1−xNx/GaAs heterostructure properties
Authors: Saidi F. , Hassen F. , Maaref H. , Auvray L. , Dumont H. , Monteil Y.
Published: January 2004

We have investigated, by photoluminescence (PL), the optical properties of GaAs1−xNx/GaAs epilayers and GaAs1−xNx/GaAs quantum well (QW) structures grown by metal organic vapor phase epitaxy (MOVPE) on (001)‐oriented GaAs substrates. Different behaviors have been observed for the bulk epilayer and for the QW structures, respectively: (i) a blue shift of the PL bands in both kinds of structures when increasing the excitation density, (ii) an S‐shaped PL peak energy versus temperature dependence has been observed for the GaAsN epilayer but a usual behavior is obtained for the QWs. Based in these experimental results, we have suggested that the carrier recombination mechanisms in the epilayer and in the quantum well structure are different. An enhanced exciton‐localization‐like mode for the epilayer is observed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Superconducting and Vickers hardness properties of ZnO‐added YBCO polycrystalline superconductors
Authors: Kölemen U. , Çelebi S. , Karal H. , Öztürk A. , Çevik U. , Nezir S. , Görür O.
Published: January 2004

The effects of ZnO addition on the microstructure and mechanical properties of the YBCO have been investigated through XRD, SEM, EDX, ac susceptibility measurements and the standard Vickers microhardness testing method. We have prepared the samples by a conventional solid‐state reaction method and used an additive method for the YBCO system (0, 0.5 and 1 wt% of ZnO). The orthorhombic strain Δ = (b – a)/(b + a) increases as the Zn content increases, where a and b are the relevant lattice parameters of the samples. The superconducting transition temperatures and hardness depend on the Zn content of the samples. The hardness is found to be load dependent. From the relation between applied load F and the square of the impression diagonal, d2, the true hardness, H0, and the dissipative portion of the indentation load F0, were derived from the slope and the intercept (at d2 = 0) of the straight line, respectively. The hardness was increased while the transition temperature decreased with the amount of ZnO addition to YBCO. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Screw dislocation in two dissimilar piezoelectric layers
Authors: Liu Jin‐xi
Published: January 2004

The elastic and electrical fields produced by a straight screw dislocation in two dissimilar piezoelectric layers are derived through the use of conformal mapping technique, where the solution for a semi‐infinite piezoelectric bimaterial is used as a base. The expression for the image force acting on the dislocation is given explicitly. The equilibrium position of the dislocation is further determined by letting the image force be equal to zero. In the case where one of the two layers is pure elastic, the numerical results for the image force are provided to illustrate the influence of piezoelectric effect on the behavior of the dislocation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evolution of molecular ordering and phase transitions in C60/C70solid solutions
Authors: Rueda‐Morales Gabriela , Ortiz‐López Jaime
Published: January 2004

Polycrystalline solid solutions (C60)x:(C70)1−xwith 0 ≤x≤ 1 grown by sublimation are studied with AC calorimetry in the 5–300 K temperature range and with X‐ray powder diffraction at room temperature. For concentrations 0.15 ≤x≤ 0.68, an hexagonal disordered (hcp) single phase is found at room temperature with no evidence of phase transitions occurring down to 5 K. This is indication of complete C60/C70miscibility and of freezing of orientational disorder at low temperature for this concentration range. Phase transitions below room temperature are detected only for concentrations close to the pure fullerenes, with critical temperatures decreasing asxdeparts away fromx= 0 and 1. The elastic dipole model is applied in pure C70and C70‐rich solid solutions to account for elastic interactions and ferroelastic ordering of the elongated C70molecule. Within this model, the evolution of ferroelastic phase transitions in C70‐rich solid solutions is obtained and compared with available experimental data. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Rhus coriaria L. (Anacardiaceae) on lipid peroxidation and free radical scavenging activity
Authors: Candan Ferda , Sökmen Atalay
Published: January 2004

In order to evaluate the antioxidant potential of Rhus coriaria L. (Anacardiaceae), a well‐known spice, the methanolic extract (water‐soluble part) was prepared and investigated using free radical‐generating systems in vitro. The IC50 value of the extract for lipid peroxidation was estimated as 1200 µg/mL in the Fe+2‐ascorbate system while those for superoxide‐scavenging activity in the xanthine‐xanthine oxidase method and hydroxyl radical scavenging activity in the deoxyribose decomposition method were 282.92 µg/mL and 3850 µg/mL, respectively. These data suggest that the methanolic extracts of Rhus coriaria L. fruits have considerable antioxidant activity against free radicals and lipid peroxidation in vitro, a fact that may encourage in vivo studies. Copyright © 2004 John Wiley & Sons, Ltd.
The evaluation of the radioprotective effect of chyavanaprasha (an ayurvedic rasayana drug) in mice exposed to lethal dose of γ‐radiation: a preliminary study
Authors: Jagetia Ganesh Chandra , Baliga Manjeshwar Shrinath
Published: January 2004

The effect of various doses of 50% ethanolic extract of chyavanaprasha (an Ayurvedic rejuvenating herbal preparation) was studied on the survival of mice exposed to 10 Gy of γ‐radiation. Treatment with chyavanaprasha, consecutively for ﬁve days before irradiation, delayed symptoms of radiation sickness and onset of mortality when compared with the non‐drug treated irradiated controls. All doses of chyavanaprasha provided a signiﬁcant protection against gastrointestinal (GI) death (death of animals within 10 days after exposure to radiation), however, highest protection against GI death was observed for 15 mg/kg chyavanaprasha. Chyavanaprasha also provided a signiﬁcant protection against the bone marrow death after 10 to 40 mg/kg. However, the best protection was seen for 15 mg/kg, where the highest number of survivors was observed at the end of 30 days post‐irradiation. The drug was non‐toxic up to a dose of 6 g/kg b. wt., the highest drug dose that could be tested. Our study demonstrates that chyavanaprasha can provide good radioprotection at a very low non‐toxic dose. Copyright © 2004 John Wiley & Sons, Ltd.
Effects of methanol extract of Cirsium japonicum var. ussuriense and its principle, hispidulin‐7‐O‐neohesperidoside on hepatic alcohol‐metabolizing enzymes and lipid peroxidation in ethanol‐treated rats
Authors: Park Jong Cheol , Hur Jong Moon , Park Ju Gwon , Kim Sang Cheol , Park Jeong Ro , Choi Seong Hee , Choi Jong Won
Published: January 2004

Effects of the methanol extract of Cirsium japonicum var. ussuriense and hispidulin 7‐O‐neohesperidoside isolated from the plant on hepatic alcohol‐metabolizing enzymes and lipid peroxidation were studied in rats treated with ethanol. Rats treated with 10% alcohol solution for 6 weeks were orally administered with 250 or 500 mg of methanol extract or 10 or 20 mg of hispidulin 7‐O‐neohesperidoside per kg body weight daily during the last week of ethanol treatment. The administration of the methanol extract of herbal plant and hispidulin 7‐O‐neohesperidoside in ethanol‐treated rats signiﬁcantly enhanced the activities of hepatic alcohol dehydrogenase, microsomal ethanol‐oxidizing system and aldehyde dehydrogenase in a dose‐dependent manner. The extract and the compound decreased hepatic lipid peroxidation along with an increase in hepatic content of reduced glutathione. The methanol extract and hispidulin 7‐O‐neohesperidoside of C. japonicum var. ussuriense also increased the activity of glutathione reductase, but had no effect on γ‐glutamylcysteine synthase. The results suggest that C. japonicum var. ussuriense may alleviate alcoholic toxicity by enhancing ethanol oxidation as well as inhibiting lipid peroxidation, and hispidulin 7‐O‐neohesperidoside is one of the active substances responsible for the protective effects of this plant. Copyright © 2004 John Wiley & Sons, Ltd.
Isolation and puriﬁcation of the hypoglycaemic principle present in Capsicum frutescens
Authors: Tolan Ian , Ragoobirsingh Dalip , Morrison Errol Y. St. A.
Published: January 2004

Capsicum frutescens has been used to treat diabetes mellitus by traditional healers in Jamaica. Puriﬁcation experiments employing thin layer chromatography (TLC) and high performance liquid chromatography led to the extraction of the active principle, capsaicin. Puriﬁed capsaicin caused a decrease in blood glucose levels to 4.91 ± 0.52 (n = 6) mmol/dL versus 6.40 ± 0.13 mmol/dL (n = 6) for the control (p < 0.05) at 2.5 h in an OGTT in dogs. There was a concomitant elevation in plasma insulin levels (p < 0.05). In conclusion, it can be stated that capsaicin is the major constituent of Capsicum frutescens that is responsible for the hypoglycaemic episodes seen in the dogs. It is also apparent that the latter is mediated by insulin release. Copyright © 2004 John Wiley & Sons, Ltd.
Antiosteoporotic activity of OST‐6(Osteocare), a herbomineral preparation in calcium deﬁcient ovariectomized rats
Authors: Reddy N. Prabhakara , Lakshmana M. , Udupa U. Venkatesh
Published: January 2004

The preventive effect of the herbal formulation OST‐6 (Osteocare) on the progress of bone loss induced by ovariectomy and concurrent calcium deﬁciency was studied in rats. Ovariectomy (OVX) and calcium deﬁciency (CD) resulted in bone loss as evident from decreased femoral weight and density. Treatment with OST‐6 at a dose of 250 mg/kg body wt twice a day orally for a period of 16 weeks signiﬁcantly restored the femoral weight and density. The biomechanical strength of the tibia was decreased by OVX and CD and this was signiﬁcantly suppressed by the administration of OST‐6. Histologically decalciﬁed bone sections revealed narrowed, and the disappearance of, trabeculae and widened medullary spaces. The total numbers of tartrate‐resistant acid phosphates (TRAP) positive cells were increased signiﬁcantly in OVX animals. Treatment with OST‐6 signiﬁcantly inhibited these histopathological changes and strongly suggested that OST‐6 was effective in preventing the progress of bone loss induced by ovariectomy and concurrent calcium deﬁciency. Copyright © 2004 John Wiley & Sons, Ltd.
Chemical and biological evaluation of the essential oils of different Melaleuca species
Authors: Farag R. S. , Shalaby A. S. , El‐Baroty G. A. , Ibrahim N. A. , Ali M. A. , Hassan E. M.
Published: January 2004

The essential oils of the fresh leaves of M. ericifolia, M. leucadendron, M. armillaris and M. styphelioides were isolated by a hydrodistillation method and analysed by a gas chromatography/mass spectrometry (GC/MS) technique. The essential oil of M. ericifolia contained methyl eugenol (96.84%) as a major constituent, whereas M. leucadendron was rich in 1,8‐cineole (64.30%). The essential oil of M. armillaris was rich in 1,8‐cineole (33.93%) followed by terpinen‐4‐ol (18.79%), whereas M. styphelioides was rich in caryophyllene oxide (43.78%) and (‐) spathulenol (9.65%). The essential oils of these species possessed antimicrobial and antifungal activities. M. ericifolia exhibited the highest inhibitory effects against Bacillus subtiles and Aspergillus niger. The antiviral activities of the essential oils against Herpes simplex virus type 1 (HSV‐1) were studied in African green monkey kidney cells (Vero) by a plaque reduction assay. The volatile oil of M. armillaris was more effective as a virucidal (up to 99%) than that of M. leucadendron (92%) and M. ericifolia (91.5%). The effects of the essential oils on the antioxidant system status in carbon tetrachloride treated animals were studied. The essential oil of M. armillaris exhibited a marked antioxidant effect, it improved vitamin E, vitamin C and superoxide dismutase parameters so it can be used as a free radical suppressor. Copyright © 2004 John Wiley & Sons, Ltd.