bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid detection of varicella–zoster virus infection by a loop‐mediated isothermal amplification method
Authors: Okamoto Souki , Yoshikawa Tetsushi , Ihira Masaru , Suzuki Kayoko , Shimokata Kaoru , Nishiyama Yukihiro , Asano Yoshizo
Published: October 2004

The reliability of varicella–zoster virus (VZV) loop‐mediated isothermal amplification (LAMP) was evaluated for rapid diagnosis of viral infection. VZV‐specific primers only amplified VZV DNA; no LAMP products were observed in reactions performed with other viral DNA templates. The specificity of this method was confirmed by two independent determinations, agarose gel electrophoresis and a turbidity assay. The sensitivity of VZV LAMP, determined by agarose gel electrophoresis, were 500 copies/tube. Detection using the turbidity assay, however, gave a sensitivity of 1,000 copies/tube. After these initial validation studies, reliability of VZV LAMP was evaluated for the detection of viral DNA in clinical specimens. Thirty‐two swab samples collected from patients with vesicular skin eruptions were tested for VZV DNA. VZV was confirmed in sample numbers 10–32 by VZV real‐time PCR, a previously established technique. VZV LAMP products were detected using turbidity from samples 13 to 32 (sensitivity; 87.0%, specificity; 100%, positive predictive value; 100%, negative predictive value; 75%). Although low levels of VZV DNA could be detected in the three samples exhibiting divergent results (samples numbers 10–12), no VZV LAMP product was detected in these samples, indicating a higher detection limit for this assay. Requirement of a DNA extraction step in the VZV LAMP method was examined in next experiment. The turbidity assay detected a VZV LAMP product in all of the 20 positive swab samples (samples numbers 13–32), regardless of DNA extraction. J. Med. Virol. 74:677–682, 2004. © 2004 Wiley‐Liss, Inc.
Characterization of tick‐borne encephalitis virus from Estonia
Authors: Golovljova Irina , Vene Sirkka , Sjölander Katarina Brus , Vasilenko Veera , Plyusnin Alexander , Lundkvist Åke
Published: October 2004

Tick‐borne encephalitis virus (TBEV) is a severe problem in Estonia. In the present article the first genetic analysis of Estonian TBEV strains is described. In total, seven TBEV strains were isolated from ticks (Ixodes ricinus and I. persulcaus), rodents (Apodemus agrarius and Cletrionomys glareolus), and serum from a tick‐borne encephalitis (TBE) patient. The nucleic acid sequences of the viral genome encoding almost the complete E protein (nt 41–1250) and the 3′‐NCR‐termini of the Estonian TBEV strains were determined by direct sequencing of RT‐PCR products. The results showed that all three known TBEV subtypes, Western TBEV (W‐TBEV), Far‐Eastern TBEV (FE‐TBEV), and Siberian TBEV (S‐TBEV), co‐circulate in Estonia. The Estonian TBEV strains of the S‐TBEV and W‐TBEV subtypes clustered with the previously reported strains from Latvia and Lithuania. Within the FE‐TBEV subtype, however, the Estonian strain Est2546 clustered together with the strain Sofjin, originating from the Far‐East of Russia, but not with the strain RK1424, isolated in the neighboring Latvia. This suggests a different evolutionary history for the Estonian and the Latvian strains in the FE‐TBEV subtype. The Estonian TBEV strain (Est3535), which belonged to the S‐TBEV subtype, had an organization of the 3′‐NCR similar to that of strains from the Far‐East of Russia (Irkutsk). The 3′‐NCRs of Estonian strains of the W‐TBEV subtype (Est3051, Est3053, Est3476, and Est3509) were very similar to those of the strain Ljubljana I from the Balkans. In the 3′‐NCR sequence of the Estonian strain Est2546, which belonged to the FE‐TBEV subtype, a deletion from position 10461 to 10810 extending approximately 10 nucleotides into the core element, was detected. J. Med. Virol. 74:580–588, 2004. © 2004 Wiley‐Liss, Inc.
Changes in the hemagglutinins and neuraminidases of human influenza B viruses isolated in Italy during the 2001–02, 2002–03, and 2003–04 seasons
Authors: Puzelli Simona , Frezza Fabiola , Fabiani Concetta , Ansaldi Filippo , Campitelli Laura , Lin Yi Pu , Gregory Victoria , Bennett Michael , D'Agaro Pierlanfranco , Campello Cesare , Crovari Pietro , Hay Alan , Donatelli Isabella
Published: October 2004

Throughout most of the last decade, B/Yamagata/16/88‐lineage influenza viruses were predominant among the B isolates circulating worldwide, whereas B/Victoria/2/87‐lineage viruses were isolated infrequently and restricted geographically to eastern Asia. During the 2001–02 influenza season, B/Victoria/2/87‐lineage viruses re‐emerged in North America and Europe and spread worldwide. Virological surveillance in Italy during that season showed wide circulation of influenza B viruses, of which most were antigenically related to the B/Sichuan/379/99 (Yamagata‐lineage) vaccine strain, together with a smaller number of B viruses antigenically similar to B/HongKong/330/01, a recent B/Victoria/2/87‐lineage antigenic variant. In the subsequent 2002–03 epidemic season, B viruses with a Victoria‐lineage hemagglutinin (HA), more closely related to that of B/Shandong/7/97, were isolated exclusively. Similar strains have continued to predominate among the few B viruses isolated in Italy during last season (2003–04), although most influenza B viruses, isolated sporadically elsewhere in Europe, again belong to the Yamagata‐lineage. In the present study, phylogenetic analyses of the HA and neuraminidase (NA) genes of representative B strains, isolated throughout Italy during 2001–04, showed that during the first influenza season the NA genes, as well as the HA genes, separated into the two distinct clades, the Yamagata‐ and Victoria‐lineages, and showed no evidence of genetic reassortment. On the contrary, all the B viruses isolated in the 2002–03 and most of those isolated in the 2003–04 epidemic season were “Victoria HA–Yamagata NA” reassortants similar to those isolated in other parts of the world, showing that these reassortants became established in the human population. The frequency of reassortment between HA and NA of distinct lineages and sublineages highlights again the importance of detailed molecular analyses of both surface glycoproteins in understanding the evolution of influenza B viruses. J. Med. Virol. 74:629–640, 2004. © 2004 Wiley‐Liss, Inc.
Culture adaptation of serotype G6 human rotavirus strains from hospitalized diarrhea patients in India
Authors: Kelkar S.D. , Dindokar A.R. , Dhale G.S. , Zade J.K. , Ranshing S.S.
Published: October 2004

During serotyping of fecal specimens positive for rotavirus from hospitalized diarrhea patients in Pune, India, about 10% showed multireactivity in enzyme immunoassay with monoclonal antibodies specific for serotypes G1–4, 6, 8, and 10. In order to characterize some of these, three fecal specimens from children and one from adult were culture adapted. All the isolates showed long RNA pattern, but three out of four isolates belonged to subgroup I and II and one, to subgroup I. The isolates were confirmed as G6 by neutralization assay and polymerase chain reaction. Nucleotide sequences of cDNA derived from the gene encoding the outer capsid protein, VP7 of two strains indicated >94% identity with G6, the serotype, generally associated with cattle. The isolates were more close to G6 RF strain, which is a bovine rotavirus, reported from France. This is a first report of isolation of bovine serotype, G6 from children as well as adults from India. J. Med. Virol. 74:650–655, 2004. © 2004 Wiley‐Liss, Inc.
E. coli‐expressed recombinant norovirus capsid proteins maintain authentic antigenicity and receptor binding capability
Authors: Tan Ming , Zhong Weiming , Song Dan , Thornton Scott , Jiang Xi
Published: October 2004

The baculovirus expression system has been widely used to produce the capsid proteins of Norovirus (NV) and the proteins form virus‐like particles (VLPs) that are useful in many studies, such as immunology, diagnosis, and host‐receptor interaction. We report here the application of the E. coli expression system in the production of recombinant NV capsid proteins. In a direct comparison of a previous well‐characterized NV strain (VA387), we have demonstrated that the E. coli‐expressed capsid proteins maintain the same antigenicity and receptor binding specificity as that of the baculovirus‐expressed capsid, although the E. coli‐expressed VA387 proteins did not form VLPs. Using the E. coli‐expression system, we characterized the receptor‐binding patterns of three additional NV strains (OIF1998, Parris Island and VA115), in which OIF1998 binds to HBGA of nonsecretors but did not bind or binds weakly to the HBGA of secretors, as seen in strain VA207. Parris Island binds to HBGA of types A and B but not type O secretors and nonsecretors. VA115 did not show specific binding to any A, B, O secretor nor nonsecretor, which is also observed when the capsid protein of this strain was expressed in baculovirus. Our data indicate that VLP formation is not required for receptor binding, and that the bacteria expression system offers a simple alternative for large production of NV capsid protein for various research purposes, particularly for strains generating low yields in the insect cells. J. Med. Virol. 74:641–649, 2004. © 2004 Wiley‐Liss, Inc.
Towards automation of palynology 1: analysis of pollen shape and ornamentation using simple geometric measures, derived from scanning electron microscope images
Authors: Treloar W. J. , Taylor G. E. , Flenley J. R.
Published: October 2004

This is the first of a series of papers on the theme of automated pollen analysis. The automation of pollen analysis could result in numerous advantages for the reconstruction of past environments, with larger data sets made practical, objectivity and fine resolution sampling. There are also applications in apiculture and medicine. Previous work on the classification of pollen using texture measures has been successful with small numbers of pollen taxa. However, as the number of pollen taxa to be identified increases, more features may be required to achieve a successful classification. This paper describes the use of simple geometric measures to augment the texture measures. The feasibility of this new approach is tested using scanning electron microscope (SEM) images of 12 taxa of fresh pollen taken from reference material collected on Henderson Island, Polynesia. Pollen images were captured directly from a SEM connected to a PC. A threshold grey‐level was set and binary images were then generated. Pollen edges were then located and the boundaries were traced using a chain coding system. A number of simple geometric variables were calculated directly from the chain code of the pollen and a variable selection procedure was used to choose the optimal subset to be used for classification. The efficiency of these variables was tested using a leave‐one‐out classification procedure. The system successfully split the original 12 taxa sample into five sub‐samples containing no more than six pollen taxa each. The further subdivision of echinate pollen types was then attempted with a subset of four pollen taxa. A set of difference codes was constructed for a range of displacements along the chain code. From these difference codes probability variables were calculated. A variable selection procedure was again used to choose the optimal subset of probabilities that may be used for classification. The efficiency of these variables was again tested using a leave‐one‐out classification procedure. The proportion of correctly classified pollen ranged from 81% to 100% depending on the subset of variables used. The best set of variables had an overall classification rate averaging at about 95%. This is comparable with the classification rates from the earlier texture analysis work for other types of pollen. Copyright © 2004 John Wiley & Sons, Ltd.
Holocene climate changes in southern Greenland: evidence from lake sediments
Authors: Andresen Camilla S. , Björck Svante , Bennike Ole , Bond Gerard
Published: October 2004

A Holocene lake sediment record is presented from Lake N14 situated on Angissoq Island 15 km off the main coast of southern Greenland. The palaeoclimatic development has been interpreted on the basis of flux and percentage content of biogenic silica, clastic material, organic material and sulphur as well as sedimentation rate, moss content and magnetic susceptibility. A total of 43 radiocarbon dates has ensured a reliable chronology. It is argued that varying sediment composition mainly reflects changing precipitation. By analogy with the present meteorological conditions in southern Greenland, Holocene climate development is inferred. Between 11 550 and 9300 cal. yr BP temperature and precipitation increase markedly, but this period is climatically unstable. From 9300 yr BP conditions become more stable and a Holocene climatic optimum, characterised by warm and humid conditions, is observed from 8000 to 5000 cal. yr BP. From 4700 cal. yr BP the first signs of a climatic deterioration are observed, and from 3700 cal. yr BP the climate has become more dry and cold. Superimposed on the climatic long‐term trend is climate variability on a centennial time‐scale that increases in amplitude after 3700 cal. yr BP. A climatic scenario related to the strength and position of the Greenland high‐pressure cell and the Iceland low‐pressure cell is proposed to explain the Holocene centennial climate variability. A comparison of the Lake N14 record with a terrestrial as well as a marine record from the eastern North Atlantic Ocean suggests that the centennial climate variability was uniform over large areas at certain times. Copyright © 2004 John Wiley & Sons, Ltd.
The Effect of Chain Transfer Agent Level on Adhesive Performance and Peel Master‐Curves for Acrylic Pressure Sensitive Adhesives
Authors: Gower M. D. , Shanks R. A.
Published: October 2004

Summary: Three series of pressure sensitive adhesives were prepared with fixed glass transition temperature, using emulsion polymerisation. Monomers chosen were butyl acrylate, 2‐ethylhexyl acrylate, and methyl methacrylate, along with a small amount of acrylic acid. The proportion of acrylic acid monomer was held constant for each polymer preparation while acrylate ester monomer levels were varied. The chain transfer agent level used was varied for each series of polymerisations. Adhesion performance was assessed by measurement of loop tack, static shear resistance, and through construction of peel master‐curves. Peel master‐curves were generated through peel tests conducted over a range of temperatures and peel rates and through application of the Boltzmann superposition principle. The presence of high levels of polymer gel was found to obscure the influence of monomer composition on adhesion performance. For polymers with low levels of gel, adhesion performance was correlated with changes in viscosity as comonomer composition was varied. In cohesive failure regions of peel master‐curves for polymers with high levels of chain transfer agent, the shift factors aT were found to closely fit the Williams‐Landel‐Ferry (WLF) equation and allowed the calculation of the WLF parameters, C1 and C2. The cohesive failure regions were successfully shifted to provide a “super” master‐curve and the values of aC used to generate the “super” master‐curve were applied to accurately predict relative static shear resistance levels. For low gel content polymers, loop tack was correlated with log(aC) as EHA levels were increased.

Peel master‐curve for formulation AA4M91‐3.

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Peel master‐curve for formulation AA4M91‐3.
Polyolefin/Lignosulfonate Blends, 9
Authors: Cazacu Georgeta , Mihaies Mihaela , Pascu Mihaela Cristina , Profire Lenuta , Kowarskik Alexander L. , Vasile Cornelia
Published: October 2004

Summary: In the present study, the compatibility, properties and degradability of polyolefin/lignin blends have been studied. Blends of three maleic anhydride grafted copolymers of ethylene‐propylene rubbers containing various content of functional groups with epoxy‐modified lignosulfonate have been investigated by microscopy, X‐ray diffraction, surface and mechanical indices determination, electron spin resonance, IR spectroscopy, differential scanning calorimetry and thermogravimetry. To assess the environmental degradation characteristics, the behavior of the blends during soil burial test has been investigated. The influence of the buried polymer blends on the physiological vegetative processes of the Vicia X Hybrida hort plant has been monitored.

Optical microscopy images of blend EP‐g‐MA 0.3/5 LER, undegraded (left) and degraded (right).

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Optical microscopy images of blend EP‐g‐MA 0.3/5 LER, undegraded (left) and degraded (right).
Microwave‐Assisted Polymer Synthesis: State‐of‐the‐Art and Future Perspectives
Authors: Wiesbrock Frank , Hoogenboom Richard , Schubert Ulrich S.
Published: October 2004

Summary: Monomodal microwaves have overcome the safety uncertainties associated with the precedent domestic microwave ovens. After fast acceptance in inorganic and organic syntheses, polymer chemists have also recently discovered this new kind of microwave reactor. An almost exponential increase of the number of publications in this field reflects the steadily growing interest in the use of microwave irradiation for polymerizations. This review introduces the microwave systems and their applications in polymer syntheses, covering step‐growth and ring‐opening, as well as radical polymerization processes, in order to summarize the hitherto realized polymerizations. Special attention is paid to the differences between microwave‐assisted and conventional heating as well as the “microwave effects”.

Results of search on number of publications on microwave‐assisted polymerizations, sorted by year.

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Results of search on number of publications on microwave‐assisted polymerizations, sorted by year.
Highly Sensitive and Selective Fluoride Ion Chemosensing, Fluoroalkylated Polysilane
Authors: Saxena Anubhav , Fujiki Michiya , Rai Roopali , Kim Sun‐Young , Kwak Giseop
Published: October 2004

Summary: This paper reports a new and simple approach for the amplified detection of fluoride ions by a polymer‐based chemosensor made of stiff fluoroalkylated polysilane, poly(3,3,3‐trifluoropropylmethylsilane). This chemosensor exhibited extreme sensitivity and selectivity towards fluoride ions by a decrease in the photoluminescence (PL) intensity with parts per billion concentrations of fluoride ions in solution in tetrahydrofuran (THF). The quenching constant for fluoride ions (K = 1.35 × 107 M−1) was found to be exceptionally high.

Schematic representation of the polymer amplification mechanism after addition of fluoride ion in tetrahydrofuran.

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Schematic representation of the polymer amplification mechanism after addition of fluoride ion in tetrahydrofuran.
Abnormalities in the NF‐κB family and related proteins in endometrial carcinoma
Authors: Pallares Judit , Martínez‐Guitarte Jose Luis , Dolcet Xavier , Llobet David , Rue Montserrat , Palacios José , Prat Jaime , Matias‐Guiu Xavier
Published: October 2004

The NF‐κB family of transcription factors regulates a wide variety of cellular processes including cell growth, differentiation, and apoptosis. A tissue microarray was constructed from paraffin wax‐embedded blocks from 95 endometrial carcinomas (EC), previously studied for microsatellite instability, as well as for alterations in PTEN, k‐RAS and beta‐catenin. Immunohistochemical evaluation included members of the NF‐κB (p50, p65, p52, c‐Rel, Rel‐B) and the IκB (IκBα, IκBβ, IκBε, Bcl‐3) families, as well as putative targets of NF‐κB such as Flip, Bcl‐xL, Cyclin D1, and oestrogen and progesterone receptors. Results were correlated with the clinical and pathological data. Nuclear immunostaining for members of the NF‐κB family was frequent in EC (p50, 20%; p65, 16.5–21.9%; p52, 9.3%; c‐Rel, 48.9%; Rel‐B, 15.7%); and it correlated with negativity for members of the IκB family in some cases. There was a statistically significant association between immunoreaction for p50 and p65 (p = 0.006), suggesting activation of the so‐called ‘classic form’ of NF‐κB, similar to that described in breast cancer. Bcl‐3 nuclear immunostaining was detected in 60.7% of cases. The vast majority of p52‐positive tumours showed Bcl‐3 nuclear immunoreaction (p = 0.038). Immunostaining for putative targets of NF‐κB was as follows: Bcl‐xL, 76.2% (p = 0.001); Flip 43.0%; Cyclin D1, 64.79%. p65 immunostaining correlated with increased immunoreaction for steroid hormone receptors. No correlation was found between NF‐κB nuclear pattern and the presence of microsatellite instability, or alterations in PTEN, k‐RAS, or beta‐catenin. These results suggest that the NF‐κB and IκB families of genes may be important in endometrial carcinogenesis, by controlling apoptosis and cell proliferation. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Combined analysis of the essential oil of Chenopodium ambrosioides by GC, GC‐MS and 13C‐NMR spectroscopy: quantitative determination of ascaridole, a heat‐sensitive compound
Authors: Cavalli Jean‐François , Tomi Félix , Bernardini Antoine‐François , Casanova Joseph
Published: October 2004

A commercial sample of the essential oil of Chenopodium ambrosioides L. from Madagascar was analysed by GC, GC‐MS and 13C‐NMR. By GC analysis, the major constituents were found to be ascaridole (1) (41.8%), isoascaridole (2) (18.1%), p‐cymene (16.2%), α‐terpinene (9.7%) and limonene (3.8%). However, ascaridole undergoes a partial thermal isomerisation to 2 and hence the amount of 1 is under‐estimated by GC analysis. The actual contents of 1 and 2 (55.3 and 4.6%, respectively) were obtained following combined analysis of the sample by GC and 13C‐NMR. Several hydroxy‐ and polyhydroxy‐menthanes were identiﬁed by 13C‐NMR. Copyright © 2004 John Wiley & Sons, Ltd.
Chemical fingerprinting of Andrographis paniculata using HPLC, HPTLC and densitometry
Authors: Srivastava Alpana , Misra Himanshu , Verma Ram K. , Gupta Madan M.
Published: October 2004

An attempt has been made to develop a method by which to determine the chemical ﬁngerprint of Andrographis paniculata (Acanthaceae). High‐performance thin layer chromatography (HPTLC) was used to analyse hexane, chloroform, methanol and water extracts of leaves of A. paniculata. A computerised densitometer was applied to the two‐dimensional spectrographic image analysis of the HPTLC plates. An HPLC equipped with a photodiode array detector was used for the analyses of these different extracts. The analyses showed that andrographolide and neoandrographolide are absent in the hexane extract but are present in greater amounts in the methanol extract as compared with the other extracts. These chromatograms may serve as a chemical ﬁngerprint of the drug A. paniculata for quality control purposes and in the preparation of formulations based on the drug. Copyright © 2004 John Wiley & Sons, Ltd.
Seasonal, populational and ontogenic variation in the volatile oil content and composition of individuals of Origanum vulgare subsp. Hirtum, assessed by GC headspace analysis and by SPME sampling of individual oil glands
Authors: Johnson Christopher B. , Kazantzis Athanasios , Skoula Melpomeni , Mitteregger Ulli , Novak Johannes
Published: October 2004

Small‐scale GC headspace analyses combined with SPME sampling of individual oil glands have been used to measure the variation in volatile content and composition in and within different oregano plants as affected by age, season and developmental state. The main monoterpenes found were p‐cymene, carvacrol and their precursor γ‐terpinene. The early season preponderance of p‐cymene over carvacrol was reversed as the season progressed and this pattern could also be seen at any time within the plant, from the latest leaves to be produced (low in cymene) to the earliest (high in cymene). Seedlings from the same mother plant developed this pattern at different rates. Within individual leaves the pattern was not observed, even within the youngest developing leaves. However it was found that the oil composition of individual glands within a single leaf varied considerably, most notably in respect of the production of carvacrol and its isomer thymol. Copyright © 2004 John Wiley & Sons, Ltd.
Isoﬂavonoids in the rutaceae family: 1. Fortunella obovata, Murraya paniculata and four Citrus species
Authors: Lapčík Oldřich , Klejdus Bořivoj , Davidová Michaela , Kokoška Ladislav , Kubáň Vlastimil , Moravcová Jitka
Published: October 2004

Several types of compounds with immunoreactivity similar to isoﬂavonoids were detected in water: ethanol extracts of leaves of Fortunella obovata Hort. ex Tanaka, Murraya paniculata Jack. and four Citrus species, namely C. aurantium L., C. grandis Osbeck, C. limonia Osbeck., and C. sinensis Osbeck (Rutaceae). The chromatographic mobilities of the immunoreactive substances were compared with those of authentic standards, revealing a spectrum of isoﬂavonoid metabolites in all plants studied. Aglycones as well as glycosides were recognized, namely daidzin, genistin, daidzein, genistein, formononetin, biochanin A, prunetin, and several incompletely characterized isoﬂavonoids. A subsequent HPLC‐MS study veriﬁed the identities of the main immunoreactive isoﬂavonoids and established the identities of several others, viz. glycitein, glycitin, ononin and sissotrin, including the malonylated and acetylated isoﬂavonoid glucosides. The estimated content of the individual immunoreactive entities ranged from a few µg to about 2 mg/kg (dry weight). It is concluded that the isoﬂavonoid metabolic pathway is present throughout the Rutaceae family. Copyright © 2004 John Wiley & Sons, Ltd.
Solvent effects on focused microwave assisted extraction of polyphenolic acids from Eucommia ulmodies
Authors: Li Hui , Chen Bo , Nie Lihua , Yao Shouzhuo
Published: October 2004

An open microwave‐assisted extraction system was used to extract gallic acid, protocatechuic acid, chlorogenic acid and caffeic acid from Eucommia ulmodies. The effect of extraction variables, especially solvent, on the recoveries of these polyphenolic compounds was investigated using factorial design. As extracting solvent for these compounds, methanol produced a higher recovery than pure water. For straight chain alcohol solvents, the lower the carbon number, the higher the recoveries of the polyphenolic acids. The optimal ratio of methanol:water:glacial acetic acid in the solvent mixture used in microwave‐assisted extraction was 2:8:0.3 (v/v) and this solvent could be directly used as the mobile phase in HPLC separation without additional intermittent treatment as reported in literature. The extraction under the condition of 50% microwave power and 30 s irradiation at a solvent:sample ratio of 10 (mL/g) was found to be the most advantageous. The repeatability test of extraction and chromatographic analysis was satisfactory for the analysis of these polyphenolic compounds. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of extraction method on the yield of furanocoumarins from fruits of Archangelica ofﬁcinalis Hoffm.
Authors: Waksmundzka‐Hajnos M. , Petruczynik A. , Dragan A. , Wianowska D. , Dawidowicz A.L.
Published: October 2004

Optimal conditions for the extraction and analysis of furanocoumarins from fruits of Archangelica ofﬁcinalis Hoffm. have been determined. The following extraction methods were used: exhaustive extraction in a Soxhlet apparatus, ultrasonication at 25 and 60°C, microwave‐assisted solvent extraction in open and closed systems, and accelerated solvent extraction (ASE). In most cases the yields of furanocoumarins were highest using the ASE method. The effects of extracting solvent, temperature and time of extraction using this method were investigated. The highest yield of furanocoumarins by ASE was obtained with methanol at 100–130°C for 10 min. The extraction yields of furanocoumarins from plant material by ultrasonication at 60°C and microwave‐assisted solvent extraction in an open system were comparable to the extraction yields obtained in the time‐ and solvent‐consuming exhaustive process involving the Soxhlet apparatus. Copyright © 2004 John Wiley & Sons, Ltd.
Thermal decomposition, combustion and flame‐retardancy of epoxy resins—a review of the recent literature
Authors: Levchik Sergei V , Weil Edward D
Published: October 2004

An overview of the recent literature on combustion and flame‐retardancy of epoxy resins is presented. A brief overview of the structures of cured epoxy resins is also presented as a background for better understanding of the thermal decomposition and combustion phenomena. The literature sources were mostly taken from the publications of 1995 and later; however, for basic descriptions of the structural and thermal decomposition principles, older publications are also cited. New developments in flame‐retardant additives, epoxy monomers and curing agents are described. It is shown that the main attention in recent years has been focused on phosphorus‐containing epoxy monomers and epoxy resins. Silicon‐containing or nitrogen‐containing products and inorganic additives remain of great interest as supplementary materials to phosphorus flame‐retardants. Copyright © 2004 Society of Chemical Industry
Synthesis of graft copolymer polyethylene‐ graft‐poly(ethylene oxide) by a new anionic graft‐from polymerization
Authors: Lu Yingying , Chen Shangtao , Hu Youliang , Chung TC
Published: October 2004

A series of amphiphilic graft copolymers, PE‐graft‐PEO, containing hydrophobic polyethylene (PE) as the backbone and hydrophilic poly(ethylene oxide) (PEO) as the side‐chain, have been synthesized by a novel route. The graft structure and the molecular weight, as well as the molecular weight distribution of the graft copolymer can easily be controlled. The molecular weight of the side‐chain PEO is proportional to the reaction time and the monomer concentration, which indicates the ‘living’ character of the anionic polymerization of ethylene oxide. The produced copolymers PE‐graft‐PEO were characterized by 1H NMR and DSC measurements. Copyright © 2004 Society of Chemical Industry
Poly(ethylene oxide)‐block‐polystyrene copolymers obtained by radical polymerization involving chain‐transfer processes
Authors: Teodorescu Mircea , Dimonie Mihai , Draghici Constantin , Vasilievici Gabriel
Published: October 2004

Poly(ethylene oxide)‐block‐polystyrene (PEO–PSt) block copolymers were prepared by radical polymerization of styrene in the presence of iodoacetate—terminated PEO (PEO‐I) as a macromolecular chain‐transfer agent. PEO‐I was synthesized by successively converting the OH end‐group of α‐methoxy ω‐hydroxy PEO to chloroacetate and then to the iodoacetate. The chain‐transfer constant of PEO‐I was estimated from the rate of consumption of the transfer agent versus the rate of consumption of the monomer (Ctr, PEO‐I = 0.23). Due to the involvement of degenerative transfer, styrene polymerization in the presence of PEO‐I displayed some of the characteristics of a controlled/‘living’ process, namely an increase in the molecular weight and decrease of polydispersity with monomer conversion. However, because of the slow consumption of PEO‐I due to its low chain‐transfer constant, this process was not a fully controlled one, as indicated by the polydispersity being higher than in a controlled polymerization process (1.65 versus < 1.5). The formation of PEO–PSt block copolymers was confirmed by the use of size‐exclusion chromatography and 1H NMR spectroscopy. Copyright © 2004 Society of Chemical Industry
Functionally‐modified egg white albumen hydrogels
Authors: Rathna GVN , Li J , Gunasekaran S
Published: October 2004

Hydrogels were prepared by using egg white albumen (EWA) before and after chemical modification of its lysyl residues with ethylenediamine tetraacetic dianhydride (EDTAD) to incorporate carboxylic groups. This resulted in an increase in swelling ratio of the EWA hydrogels. The swelling ratio increased dramatically in deionized water substantially, more than in pH 7.4 buffer solution. The effects of medium pH, temperature and swelling were investigated, along with crosslinking of the gel network by glutaraldehyde (GLA), as well as acetone treatment. The gels denatured by acetone showed an insignificant increase in swelling ratio for the gels crosslinked with GLA during gel preparation, which is in contrast to the gels crosslinked subsequent to gel formation. The swelling behavior was positively affected by temperature and time. However, an insignificant effect of pH was observed due to electrostatic screening of the carboxylic groups by sodium ions in the buffer solution. Availability of various functional groups on EWA has resulted in adsorption of metals (Cu+2 ions) and non‐metals (PO4−2 anions). Copyright © 2004 Society of Chemical Industry
Alternating copolymerization and terpolymerization of vinyl‐substituted phenolic antioxidants with propene and carbon monoxide by a palladium(II)‐based catalyst: polyketones containing intramolecular stabilizers
Authors: Auer Markku , Kettunen Mika , Abu‐Surrah Adnan S , Leskelä Markku , Wilén Carl‐Eric
Published: October 2004

The copolymerization and terpolymerization reactions of the vinyl‐substituted phenolic stabilizers, 6‐tert‐butyl‐2‐(1,1‐dimethylhept‐6‐enyl)‐4‐methylphenol, o‐allylphenol, 4‐methylstyrene‐2,6‐di‐tert‐butylphenol and 2,6‐di‐tert‐butyl‐4‐allylphenol, with propene and carbon monoxide, by using the solvent‐stabilized palladium(II) phosphine complex [Pd(dppp)(NCCH3)2](BF4)2 (dppp, 1,3‐bis(diphenylphosphino)propane) as a catalyst precursor and methanol as a co‐catalyst, is described. The influence of functional α‐olefins/CO units, distributed statistically along the propene/carbon monoxide (P/CO) copolymer backbone, on the molecular weight, glass transition temperature (Tg), elastic behavior and stability of the high‐molecular‐weight P/CO copolymer has been investigated. Loss of both elasticity and transparency were observed upon incorporating o‐allylphenol as a termonomer. The terpolymers, which contain phenolic stabilizers, were shown to be more stable when compared to the stabilizer‐free polyketones. In contrast to the propene/carbon monoxide copolymer, no degradation was observed for the 2,6‐di‐tert‐butyl‐4‐allylphenol/P/CO terpolymer; instead, the molar masses increased. Copyright © 2004 Society of Chemical Industry
Miscibility and thermal and dynamic mechanical behaviour of semi‐interpenetrating polymer networks based on polyurethane and poly(hydroxyethyl methacrylate)
Authors: Karabanova Lyudmila V , Boiteux Gisele , Gain Olivier , Seytre Gerard , Sergeeva Lyudmila M , Lutsyk Elena D
Published: October 2004

The thermodynamic miscibility and thermal and dynamic mechanical behaviour of semi‐interpenetrating polymer networks (semi‐IPNs) of crosslinked polyurethane (PU) and linear poly(hydroxyethyl methacrylate) (PHEMA) have been investigated. The free energies of mixing of the semi‐IPN components have been determined by the vapour sorption method and it was established that the parameters are positive and depend on the amount of PHEMA in the semi‐IPN samples. Thermal analyses glass transition temperatures evidenced two in the semi‐IPNs in accordance with the investigation of the thermodynamic miscibility of these systems. Dynamic mechanical analysis revealed a pronounced change in the viscoelastic properties of the PU‐based semi‐IPNs with different amounts of PHEMA in the samples. The semi‐IPNs have two distinct tan δ maxima related to the relaxations of the two polymers in their glass temperature domains. The temperature position of PU relaxation maximum tan δ is invariable but its amplitude decreases in the semi‐IPNs with increasing amount of PHEMA in the systems. The tan δ maximum of PHEMA is shifted to a lower temperature and its amplitude decreases with increasing amount of PU in the semi‐IPNs. The segregation degree of components α was calculated using the viscoelastic properties of semi‐IPNs. It was concluded that the studied semi‐IPNs are two‐phase systems with incomplete phase separation. The different levels of immiscibility lead to the different degree of phase separation in the semi‐IPNs with compositions. Copyright © 2004 Society of Chemical Industry
Predicting the permeability and tensile behavior of high density polyethylene/tie/polyamide 6 three‐layer films
Authors: Huang Chi‐Hsien , Wu Jiann‐Shing , Huang Chun‐Chin
Published: October 2004

Multilayer films with multiple properties have been widely applied in the packaging industry. In order to know the two most important properties,iepermeability and tensile property, of the multilayer films, we examined model predictions and the properties of the individual component layers to provide an efficient method to design desired multilayer structures. The series model was employed for predicting permeability; there is good agreement between experimental data and this model for predicting both gas and water vapor permeabilities of three‐layer films with various thickness fractions of polyamide 6 (PA‐6). We can also predict the parameters of the constitutive equation, which described the plastic deformation of the three‐layer films, from those of the individual component layers, with particularly high accuracy by using the additive rule. However, there was a larger discrepancy between the model and experimental data at high crosshead speeds due to the generation of heat during deformation. Copyright © 2004 Society of Chemical Industry
Synthesis and characterization of conducting copolymers of poly(vinyl alcohol) with thiophene side‐groups and pyrrole
Authors: Sahmetlioglu Ertugrul , Yuruk Huseyin , Toppare Levent , Cianga Ioan , Yagci Yusuf
Published: October 2004

Graft copolymers of poly(vinyl alcohol) with thiophene side‐groups and pyrrole were synthesized by electrochemical polymerization methods. Poly(vinyl alcohol) with thiophene side‐groups (PVATh) was obtained from the reaction between poly(vinyl alcohol) (PVA) and thiophene‐3‐acetic acid. The syntheses of copolymers of PVATh and pyrrole were achieved electrochemically by using three different supporting electrolytes, p‐toluene sulfonic acid (PTSA), sodium dodecyl sulfate (SDS) and tetrabutylammonium tetrafluoroborate (TBAFB). Characterization of PVATh and graft copolymers was performed by a combination of techniques including cyclic voltammetry, scanning electron microscopy, thermal gravimetry, differential scanning calorimetry, size‐exclusion chromatography, 1H NMR and FT‐IR. The conductivities were measured by the four‐probe technique. Copyright © 2004 Society of Chemical Industry
Morphology and dynamic mechanical properties of natural rubber/nitrile rubber blends containing trans‐polyoctylene rubber as a compatibilizer
Authors: Kader MA , Kim WD , Kaang S , Nah C
Published: October 2004

The use of trans‐polyoctylene rubber (TOR) as a compatibilizer for blends of natural rubber (NR) and acrylonitrile‐butadiene rubber (NBR) was investigated using atomic force microscopy (AFM) and dynamic mechanical analysis (DMA). The NR/NBR blends containing varying proportions of TOR were prepared in an internal mixer. AFM micrographs of NR/NBR blend at 50/50 (w/w) composition showed heterogeneous phase morphology with NR as a matrix and NBR as a dispersed phase. Inclusion of TOR in the NR/NBR blend altered the phase morphology by reducing the size of the NBR phase. DMA of NR/NBR/TOR showed reduction in tan δ peak height of NBR and an increase in storage modulus E′ in the rubbery region for the NR/NBR blends. A comparison of the E′ obtained from experimental data with that from theoretical models was made to deduce the location of TOR in the blend. Based on the fittings of calculated and experimental values of E′, it was inferred that TOR was incorporated into the NR phase at lower proportion as well as at the interfacial region at higher proportion. The Cole–Cole plot illustrated the compatibilizing effect of TOR. Copyright © 2004 Society of Chemical Industry
Synthesis of π‐conjugated poly(dithiafulvene) by cycloaddition polymerization of aldothioketene from a bis(1,2,3‐thiadiazole) monomer
Authors: Naka Kensuke , Gelover‐Santiago Adriana , Chujo Yoshiki
Published: October 2004

A π‐conjugated poly(dithiafulvene) (2) was obtained by the cycloaddition polymerization of aldothioketene with its alkynethiol tautomer derived from 1,4‐bis(1,2,3‐thiadiazolyl‐4‐yl)benzene (1) in a 94% yield. To a mixure of 1 and dimethyl sulfoxide (DMSO)/ethanol (5/1, v/v), KOH was added. After stirring the mixture overnight, piperidine was added to quench the terminal thioketenes. The reaction mixture was then poured into water to obtain the product. The cycloaddition polymerization of aldothioketene derived from 1 with its alkynethiol tautomer was studied under various conditions in several solvent systems. The structure of the polymer was supported by the 1H NMR and 13C NMR spectra. The number‐average degree of polymerization (DP) of 2 was 8, estimated from the 1H NMR analysis. Optical properties and electrochemical analysis of 2 were also studied. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5872–5876, 2004
Synthesis and properties of the [2.2]paracyclophane‐containing conjugated polymer with benzothiadiazole as an electron acceptor
Authors: Morisaki Yasuhiro , Ishida Tamao , Tanaka Hiroyuki , Chujo Yoshiki
Published: October 2004

A novel donor–acceptor type conjugated polymer based on PPE with [2.2]paracyclophane and benzothiadiazole units in the main chain was synthesized by the Sonogashira coupling reaction. The obtained polymer was quite soluble in common organic solvents, and the transparent and uniform thin film of the polymer was obtained easily by casting or spin‐coating from a toluene solution. The polymer showed an extension of π‐delocalization via the through‐space with π‐π stacking according to the UV–visible (UV–vis) absorption spectra in comparison with that of the model compound. The polymer exhibited orange photoluminescence in solution (fluorescence quantum efficiency = 0.13) and in the solid state. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5891–5899, 2004
Investigation of the effects of silicate modification on polymer‐layered silicate nanocomposite morphology
Authors: Kurian Mary , Dasgupta Arnab , Beyer Frederick L. , Galvin Mary E.
Published: October 2004

The morphological behavior of a series of polymer‐layered silicate nanocomposites (PLSNs) has been investigated. The goal was to probe the effect of “textured” silicate surfaces on PLSN morphology. The nanocomposites were fabricated by mixing montmorillonite clay that was carefully modified with tailor‐made polystyrene (PS) surfactants into a PS homopolymer matrix, where the chemical similarity of the matrix polymer and surfactants assures complete miscibility of surfactant and homopolymer. To examine the effect of silicate surface “texture,” clay was modified with combinations of long and short surfactants. The samples were then direct melt annealed to allow the equilibrium morphology to develop, and characterized by small‐angle X‐ray scattering. Based on the implications of the Balazs model and other work on the wetting behavior of polymer melts with longer surfactants and textured surfaces we expected that the intercalation of the homopolymer matrix material into the modified clay would be promoted. Extensive characterization of both the modified clays as well as the resultant nanocomposites clearly show that the modified clays exhibit a high degree of order, but also that only phase‐separated morphologies are formed in the corresponding nanocomposites. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4075–4083, 2004
In‐situ microfibrillar PET/iPP blend via slit die extrusion, hot stretching, and quenching: Influence of hot stretch ratio on morphology, crystallization, and crystal structure of iPP at a fixed PET concentration
Authors: Li Zhong‐Ming , Li Liang‐Bin , Shen Kai‐Zhi , Yang Ming‐Bo , Huang Rui
Published: October 2004

The in situ microfibrillar blend of poly(ethylene terephthalate) (PET)/isotactic polypropylene (iPP) was fabricated through a slit die extrusion, hot stretch, and quenching process. The morphological observation indicates that while the unstretched blend appears to be a common incompatible morphology, the hot stretched blends present PET in situ fibers whose characteristics, such as diameter and aspect ratio, are dependent on the hot stretching ratio (HSR). When the HSR is low, the elongated dispersed phase particles are not uniform at all. As the HSR is increased to 16.1, well‐defined PET microfibers were generated in situ, whose diameter is rather uniform and is around 0.6 ∼ 0.9 μm. The presence of the PET phase shows significant nucleation ability for crystallization of iPP. Higher HSR corresponds to faster crystallization of the iPP matrix, while as HSR is high up to a certain level, its variation has little influence on the onset and maximum crystallization temperatures of the iPP matrix during cooling from melt. Optical microscopy observation reveals that transcrystalline layers form in the microfibrillar blend, in which the PET microfibers play as the center row nuclei. In the as‐stretched microfibrillar blends, small‐angle X‐ray scattering measurements show that matrix iPP lamellar crystals have the same orientation as PET lamella. The long period of lamellar crystals of iPP is not affected by the presence of PET micofibers. Wide‐angle X‐ray scattering reveals that the β phase of iPP is obtained in the as‐stretched blends, whose concentration increases with the increase of the HSR. This suggests that finer PET microfibers can promote the occurrence of the β phase. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4095–4106, 2004
First‐order correlation‐kinetic contribution to Kohn–Sham exchange charge density function in atoms, using quantal density functional theory approach
Authors: Sen K. D. , Luque F. Javier
Published: October 2004

Using the static exchange‐correlation charge density concept, the total integrated exchange‐charge density function is calculated within the nonrelativistic spin‐restricted exchange‐only (i) optimized effective potential model, and (ii) nonvariational local potential derived from the exchange‐only work potential within the quantal density functional theory, for the ground‐state isoelectronic series: Ga+, Zn, Cu−; In+, Cd, Ag−; and Tl+, Hg, Au−. The difference between the exchange charge density function derived from these potentials is employed to evaluate the first‐order correlation‐kinetic contribution to the integrated exchange charge density. This contribution is found to be important for both the intra‐ and inter‐shell regions. Screening effects on the contribution due to the nd10 (n = 3–5) subshells are discussed through comparisons with similar calculations on Ca, Sr, and Ba, wherein nd10 electrons are absent. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Where are the angles? Angular dependence (and independence) of orbitals and functions
Authors: Liebman Joel F. , Herman Zelek S.
Published: October 2004

Certain conditions under which a collection of atomic orbitals becomes angularly independent are considered. The results are applied to molecules of chemical interest. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Supersymmetry approaches to the radial bound states of the hydrogen‐like atoms
Authors: Chenaghlou A. , Fakhri H.
Published: October 2004

Introducing the associated Bessel polynomials in terms of two non‐negative integers, we factorize their corresponding differential equation into a product of first‐order differential operators by four different ways as shape invariance equations. Then, the radial part of the bound states of the Schrödinger equation of a hydrogen‐like atom is derived using one of the factorization methods in the framework of supersymmetric quantum mechanics. In this approach, we regenerate the radial bound states and their corresponding spectrum, which are consistent with the well‐known facts. Based on the generalization of the supersymmetry idea, we shall show that two hydrogen‐like atoms with the same energy of the electron possess three extra supersymmetric structures in addition to an ordinary one. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005