bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melt spun thermoresponsive shape memory fibers based on polyurethanes: Effect of drawing and heat‐setting on fiber morphology and properties
Authors: Kaursoin Jasmeet , Agrawal Ashwini K. 
Published: November 2006

AbstractThermoresponsive shape memory (SMP) fibers were prepared by melt spinning from a polyester polyol‐based polyurethane shape memory polymer (SMP) and were subjected to different postspinning operations to modify their structure. The effect of drawing and heat‐setting operations on the shape memory behavior, mechanical properties, and structure of the fibers was studied. In contrast to the as‐spun fibers, which were found to show low stress built up on straining to temporary shape and incomplete recovery to the permanent shape, the drawn and heat‐set fibers showed significantly higher stresses and complete recovery. The fibers drawn at a DR of 3.0 and heat‐set at 100°C gave stress values that were about 10 times higher than the as‐spun fibers at the same strain and showed complete recovery on repeated cycling. This improvement was likely due to the transformation brought about in the morphology of the permanent shape of the SMP fibers from randomly oriented weakly linked regions of hard and soft segments to the well‐segregated, oriented and strongly H‐bonded regions of hard‐segments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2172–2182, 2007
Effect of natural coagula maturation on the processability, cure, and mechanical properties of unfilled vulcanizates of Hevea natural rubber
Authors: Fri Pamela Soh , Nkeng George E. , Ehabe Eugene E. 
Published: November 2006

AbstractFresh latex from different Hevea brasiliensis clones was naturally coagulated, subjected to different durations of maturation, processed into solid rubber, and compounded into pure gum stocks and vulcanized. Coagula maturation had clone‐specific effects on the processability of the raw rubber: reduced for some clones, while others was less sensitive. The cure and mechanical behaviors of the compounded stocks and vulcanizates, respectively, were not sensitive to the clonal origin of coagula and their duration of maturation. Although coagula maturation could be associated with leaching, deactivation of inherent antioxidants in Hevea latex, as well as crosslinking and/or oxidation of polyisoprene chains, these results show that compounding with a standard pure gum recipe compensates for the Hevea latex constituents affected by maturation. Hence, extended maturation of Hevea coagula, for economic or other reasons, would influence much more the bulk behavior of raw rubber and have insignificant effects on the compounded stocks and vulcanizates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2359–2363, 2007
Kinetics of graft copolymerization of poly(hexanedioic acid ethylene glycol) and methyl acrylate initiated by potassium diperiodatocuprate(III)
Authors: Bai Libin , Liu Yinghai 
Published: November 2006

AbstractA redox system, potassium diperiodatocuprate(III) [DPC]/poly(hexanedioic acid ethylene glycol) (PEA) system, was employed to initiate graft copolymers of methyl acrylate (MA) and PEA in alkaline medium. The results indicate that the equation of the polymerization rate (Rp) is as follows: Rp = k [MA]1.62[Cu(III)]0.69, and that the overall activation energy of graft polymerization is 42.5 kJ/mol. The total conversion at different conditions (concentration of reactants, temperature, concentration of the DPC, and reaction time) was also investigated. The infrared spectra proved that the graft copolymers were synthesized successfully. Some basic properties of the graft copolymer were studied by instrumental analyses, including thermogravimetry and scanning electron microscope. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2376–2381, 2007
Variety of photoluminescence intensity of fluorescent whitening agents introduced into polyacrylonitrile nanofibers
Authors: Wang Shugang , Yang Qingbiao , Du Jianshi , Bai Jie , Li Yaoxian 
Published: November 2006

AbstractThe major objective in this study was the preparation of polyacrylonitrile (PAN) nanofibers composed of 1,4‐bis(o‐cyanostyryl)benzene (ER) and 1‐(o‐cyanostyryl)‐4‐(p‐cyanostyryl)benzene (EB), two kinds of fluorescent whitening agents widely used in the textile industry. The scanning electron microscopy images revealed that the diameters of ER/PAN and EB/PAN fibers ranged from 78 to 154 nm. The IR spectra indicated that the peaks of the CN group blueshift and the generation of a shoulder peak were obviously due to the interaction between ER or EB and PAN. Furthermore, the UV spectra demonstrated that the distributive status of ER or EB tended toward the molecular state in PAN nanofibers. Finally, the most interesting finding in this study was that the photoluminescence intensity of EB/PAN nanofibers increased magnificently, whereas that of ER/PAN nanofibers decreased remarkably. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2382–2386, 2007
Radical polymerization of n‐butyl methacrylate initiated by stibonium ylide
Authors: Srivastava Sumita , Srivastava A. K. 
Published: November 2006

Abstract1,2,3,4‐Tetraphenylcyclopentadiene triphenyl stibonium ylide initiated radical polymerization of n‐butyl methacrylate (n‐BMA) in dioxane at (60 ± 0.2)°C for 90 min under nitrogen atmosphere has been carried out. The system follows nonideal kinetics, i.e., Rp α [ylide]0.2 [n‐BMA]1.8. The value of k/kt and overall energy of activation have been computed as 0.133 × 10−2 L mol−1 s−1, 33 kJ/mol, respectively. The FTIR spectrum shows a band at 1745 cm−1 due to acrylate group of n‐BMA. The 1H NMR spectrum shows a peak of two magnetically equivalent protons of methylene group at 2.1 δ ppm. The DSC curve shows glass transition temperature (Tg) as 41°C. The presence of six hyperfine lines in ESR spectrum indicates that the system follows free radical polymerization and the initiation is brought about by phenyl radical. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2457–2463, 2007
Thermooxidative aging and kinetics of the thermooxidative degradation of ethylene–propylene–diene terpolymer‐graft‐maleic anhydride/calcium carbonate composites
Authors: Zhang Jun , Yao Yong‐Zhong , Li Li , Zhou Ning‐Lin , Huang Ying‐Xia , Ma Zhen‐Mao , Shen Jian 
Published: November 2006

AbstractWe report the preparation of five different ethylene–propylene–diene terpolymer‐graft‐maleic anhydride/calcium carbonate samples with different calcium carbonate contents by precipitation and their mechanical properties and structural characterization.1 In this study, we tried to analyze the thermooxidative aging and the kinetics of thermooxidative degradation with retained tensile testing for various thermal‐aging times at 150°C and with hot‐loading‐recovery measurements. The results of the hot‐loading‐recovery measurements and retained tensile testing showed that the sample with the best crosslinked structure had the best thermooxidative‐aging resistance of all the samples. The experimental results for the thermooxidative degradation kinetics showed that the sample with the best crosslinked structure had the highest activation energy of thermal decomposition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2395–2401, 2007
Simultaneous determination of seven active components of Fufang Danshen tablet by high performance liquid chromatography
Authors: Wei Ying‐Jie , Li Song‐Lin , Li Ping 
Published: November 2006

AbstractA high‐performance liquid chromatography method was established for simultaneously determining seven major components, i.e. protocatechuic aldehyde, notoginsenoside R1, ginsenoside Rg1, salvianolic acid B, ginsenoside Rb1, cryptotanshinone and tanshinone IIA in Fufang Danshen tablet, a commonly used traditional Chinese medicinal combined prescription mainly derived from the roots of Salvia miltiorrhiza and Panax notoginseng. These seven compounds, belonging to the chemical types of phenolic acids, diterpenoid quinones and saponins, were simultaneously separated on Zorbax C18 column (250 × 4.6 mm, 5.0 µm) with the column temperature at 30°C. The mobile phase was composed of (A) aqueous phosphoric acid (0.1%, v/v) and (B) acetonitrile using a gradient elution of 7–17% B at 0–10 min, 17–20% B at 10–12 min, 20–21% B at 12–16 min, 21% B at 16–32 min, 21–29% B at 32–40 min, 29–35% B at 40–55 min, 35–65% B at 55–65 min and 65–80% B at 65–80 min; the flow rate was 1.0 mL/min. Detection wavelengths were set at 203 nm for notoginsenoside R1, ginsenoside Rg1 and ginsenoside Rb1, 281 nm for protocatechuic aldehyde, salvianolic acid B, and 270 nm for cryptotanshinone and tanshinone IIA. All calibration curves showed good linear regression (r2 > 0.9992) within test ranges. The established method showed good precision and accuracy with overall intra‐day and inter‐day variations of 0.15–4.35 and 0.61–5.17% respectively, and overall recoveries of 94.8–102.1% for the seven compounds analyzed. The developed method has been successfully applied to simultaneous evaluation of the intrinsic quality of both Danshen and Sanqi in Fufang Danshen tablets from different pharmaceutical companies. Copyright © 2006 John Wiley & Sons, Ltd.
Investigation of lipophilicity of anticancer‐active thioquinoline derivatives
Authors: Bajda Marek , Boryczka Stanisław , Wietrzyk Joanna , Malawska Barbara 
Published: November 2006

AbstractThe lipophilicity of a series of anticancer propargylthioquinoline derivatives has been investigated using chromatographic and computational methods. The parameters of relative lipophilicity (RMO and logk0) of the tested compounds were determined experimentally both by reversed‐phase thin layer (RP‐TLC), and high‐performance liquid chromatographic methods (RP‐HPLC, LiChrospher RP18 column), with mixtures of acetonitrile and water as mobile phases. Their phospholipophilicity (logk0IAM) was determined using immobilized artificial membrane HPLC (IAM. PC DD2 Regis column). Mobile phase acetonitrile concentrations were in the ranges 50–90% (RP‐TLC), 55–90% (RP‐HPLC) and 35–60% (IAM‐HPLC). The RM, logk and logkIAM values of the compounds investigated were linearly dependent on acetonitrile concentration. The analysis led to the calculation of RMO, logk0 and logk0IAM parameter values for each of the tested compounds. Their partition coefficients (logP) were also calculated with the Pallas and CAChe programs. The obtained results indicated that, among experimental methods, both RP‐TLC and RP‐HPLC gave similar results, and these methods enable the determination of lipophilicity of derivatives of thioquinolines. Using the IAM‐HPLC technique a simple method of estimation of phospholipoplilicity was described. The CAChe program might better predict calculated lipophilicity logP values, and therefore is a useful tool for the early stage of design of new propargyl thioquinolines. Copyright © 2006 John Wiley & Sons, Ltd.
Post TLC developing technique for tyrosinase inhibitor detection
Authors: Wangthong Sakulna , Tonsiripakdee Ilhum , Monhaphol Thitinun , Nonthabenjawan Ratchanee , Wanichwecharungruang Supason Pattanaargson 
Published: November 2006

AbstractPost TLC developing technique was developed to detect substances which can inhibit tyrosinase activity. The method involved spraying the TLC plate or chromatographic paper containing sample spot(s) with tyrosinase and l‐tyrosine solutions successively. A positive result could be visualized directly as white spot(s) against a brownish‐purple background. The method can either be used as a quick screening method for tyrosinase inhibitor detection or a guiding procedure for an isolation of tyrosinase inhibitors from mixtures or natural product extracts. The technique is sensitive enough to give a clear result in the presence of only 6 ng glabridin. Copyright © 2006 John Wiley & Sons, Ltd.
The Tautomeric Forms of Cyameluric Acid Derivatives
Authors: El‐Gamel Nadia E. A. , Seyfarth Lena , Wagler Jörg , Ehrenberg Helmut , Schwarz Marcus , Senker Jürgen , Kroke Edwin 
Published: November 2006

AbstractThe tautomerism of cyameluric acid C6N7O3H3 (1 a), cyamelurates and other heptazine derivatives has recently been studied by several theoretical investigations. In this experimental study we prepared stannyl and silyl derivatives of cyameluric acid (1 a): C6N7O3[Sn(C4H9)3]3 (3 a), C6N7O3[Sn(C2H5)3]3 (3 b), and C6N7O3[Si(CH3)3]3 (4). In order to investigate the structure of 1 a the mono‐ and dipotassium cyamelurate hydrates K(C6N7O3H2)⋅2 H2O (5) and K2(C6N7O3H)⋅1 H2O (6) were synthesized by UV/Vis‐controlled titration of a potassium cyamelurate solution with aqueous hydrochloric acid. Compounds 3–6 were characterized by FTIR and solid‐state NMR spectroscopy as well as simultaneous thermal analysis (TGA, DTA). The single crystal X‐ray structures of the salts 5 and 6 show that the hydrogen atoms in both anions are localized on the peripheral nitrogen atoms. This indicates—in combination with the solid‐state NMR studies—that the most stable tautomer of solid 1 a is the triketo form with C3h symmetry. However, derivatives of both the hydroxyl and the amido tautomers may be formed depending on the substituent atoms: The spectroscopic data and single crystal structures of compounds C6N7O3[Si(CH3)3]3 (4) and the solvate C6N7O3[Sn(C2H5)3]3⋅C2H4Cl2 (3 b′) show that the former is derived from the symmetric trihydroxy form of 1 a, while 3 b′ crystallizes as a chain‐like polymer, which contains the tin atoms as multifunctional building blocks, that is, bridging pentacoordinated Et3SnO2 and Et3SnON units as well as non‐bridging four‐coordinated Et3SnN units. The cyameluric nucleus is part of the polymeric chains of C6N7O3[Sn(C2H5)3]3⋅C2H4Cl2 (3 b′), by the action of both tautomeric forms of cyameluric acid, the amide and the ester form.
Organization of endogenous opioids in the rostral agranular insular cortex of the rat
Authors: Evans Joshua M. , Bey Vincent , Burkey Adam R. , Commons Kathryn G. 
Published: November 2006

AbstractThe rostral agranular insular cortex (RAIC) of rats has opioid receptors and has been implicated in the analgesic and reinforcing effects of opiates. To help in understanding the function of endogenous opioids in this structure, we sought to identify and describe the opioid peptides intrinsic to the RAIC by using immunohistochemical methods. Immunolabeling for proopiomelanocortin (POMC), the precursor to beta‐endorphin, and endomorphin 1 and 2 on sectioned rat forebrain revealed limited labeling consisting of individual varicose fibers. Immunolabeling for prodynorphin and enkephalin revealed numerous immunopositive cell bodies and fibers with distribution and morphology unique to each. Prodynorphin‐immunopositive cell bodies consisted of two types: large, lightly labeled, pyramidal‐shaped cell bodies in lamina V and more intensely labeled, small, ovoid cell bodies scattered in other lamina. Axonal fibers immunolabeled for prodynorphin varied in size and were found in all lamina. Immunolabeling for the inhibitory neurotransmitter γ‐aminobutyric acid (GABA) was rarely found in dynorphin‐containing cell bodies (6%, 10/167) but was visible within a subpopulation of axons. Enkephalin immunolabeling was detected within a single morphological subpopulation of nonpyramidal neurons located predominantly in lamina II/III, 30% (33/109) of which were also GABA immunopositive. Axons immunolabeled for enkephalin were also abundant in lamina II/III. These results suggest that dynorphin and enkephalin peptides are the predominant endogenous opioids in the RAIC and their distinct distributions suggest divergent functional roles. The localization of prodynorphin immunoreactivity to pyramidal cells suggests the possibility that this neuropeptide may be used in RAIC projection neurons, whereas enkephalin distribution was more characteristic of a role in local networks. J. Comp. Neurol. 500:530–541, 2007. © 2006 Wiley‐Liss, Inc.
The role of organizational capabilities in cleaner technology adoption: an analysis of the response of the pharmaceutical manufacturing sector in Ireland to IPC licensing regulations
Authors: Hilliard Rachel M. 
Published: November 2006

AbstractIn introducing integrated pollution control licensing, regulators hope to achieve economic advantages as well as environmental benefits. The licensing is used as a vehicle for encouraging firms to adopt cleaner technology, potentially allowing firms to achieve economic advantages through process efficiencies and reduced environmental control costs. In Ireland, the regulatory approach has been to require firms to make managerial changes in the belief that this is a necessary precursor to the take‐up of new technology. This paper examines how the pharmaceutical manufacturing sector has responded to environmental regulations that require cleaner technology adoption and managerial changes. Quantitative indicators are developed using data reported to the Irish Environmental Protection Agency. Analysis shows that firms were differentially able to implement both cleaner technology and the mandated managerial processes. The implications for policy are that regulatory instruments designed to stimulate cleaner technology may not be sufficient to promote change in firms, given that the influence of these instruments is mediated by the role of firm‐specific, experience‐based organizational capabilities. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Inverse correlation between serum PGE2 and T classification in head and neck cancer
Authors: Hambek Markus , Baghi Mehran , Wagenblast Jens , Schmitt Johannes , Baumann Helena , Knecht Rainald 
Published: November 2006

AbstractBackground.Prostaglandin E2 (PGE2) serum levels have been shown previously to be increased in tumor bearing mice as well as in patients with solid tumors; however, the impact on the course or stage of disease has not been shown. We hypothesized that PGE2 is strictly required for aggressive and especially early‐stage tumors of the head and neck to provoke invasion and angiogenesis.Methods.We analyzed the serum PGE2 levels of 100 patients with head and neck squamous cell carcinoma of different stages before and 1 year after treatment and compared the results with the serum levels of 40 healthy donors and the secretion profile of 8 different squamous cell carcinoma cell lines.Results.Our investigations showed a statistically significant inverse correlation between PGE2 serum levels and tumor stage. Furthermore, this effect has been reflected by the results of our cell culture analyses, which showed an inversely regulated PGE2 secretion into the medium during the process of proliferation. Interestingly, the serum levels of PGE2 were significantly downregulated 1 year after successful treatment.Conclusions.We conclude that PGE2 serum level as an indicator for early‐stage cancer of the head and neck may function as a tumor marker during the follow‐up period. © 2006 Wiley Periodicals, Inc. Head Neck, 2007
Mutant p53 proteins: Between loss and gain of function
Authors: Strano Sabrina , Dell'Orso Stefania , Mongiovi Adriana Maria , Monti Olimpia , Lapi Eleonora , Agostino Silvia Di , Fontemaggi Giulia , Blandino Giovanni 
Published: November 2006

AbstractCancer might result from both the aberrant activation of genes, whose physiological tuning is essential for the life of a normal cell, and the inactivation of tumor suppressor genes, whose main job is to preserve the integrity of cell genome. Among the latter, p53 is considered a key tumor suppressor gene that is inactivated mainly by missense mutations in half of human cancers. It is becoming increasingly clear that the resulting mutant p53 proteins gain oncogenic properties favoring the insurgence, the maintenance, and the spreading of malignant tumors. In this review, we mainly discuss the molecular mechanisms underlying gain of function of human tumor‐derived p53 mutants, their impact on the chemoresistance and the prognosis of human tumors, with a special focus on head and neck cancers, and the perspectives of treating tumors through the manipulation of mutant p53 proteins. © 2006 Wiley Periodicals, Inc. Head Neck, 2007
Comprehensive genomic analysis identifies MDM2 and AURKA as novel amplified genes in juvenile angiofibromas
Authors: Schick Bernhard , Wemmert Silke , Bechtel Ulrike , Nicolai Piero , Hofmann Thiemo , Golabek Wieslaw , Urbschat Steffi 
Published: November 2006

AbstractBackground.Frequent β‐catenin mutations have been detected in juvenile angiofibromas, but the tumor pathogenesis remains unknown.Methods.Metaphase‐comparative genomic hybridization (CGH) was used to identify chromosomal aberrations in 29 tumor specimens. Two tumors were investigated using genome DNA microarrays.Results.Three hundred eleven chromosomal gains and losses were detected by metaphase‐CGH. Frequent chromosomal gains were detected at 4q, 6, 12, and X, while frequent chromosomal losses affected regions of chromosomes 8, 16, 17, 22, and Y. Genome DNA microarray analysis in 2 tumors of the series confirmed chromosomal aberrations, detected by metaphase‐CGH, and indicated genes such as AURKA (20q13.2) not being recognized by metaphase‐CGH.Conclusion.Metaphase‐CGH results confirmed numerous chromosomal aberrations in juvenile angiofibromas. The most frequent aberrations affected sex chromosomes. Further consensus regions of chromosomal aberrations were detected at 4q, 6, 8, 12, 16, 17, and 22. AURKA and MDM2 were identified as interesting novel amplified genes in juvenile angiofibromas. © 2006 Wiley Periodicals, Inc. Head Neck, 2007
Flood hydrology of the Peace‐Athabasca Delta, northern Canada
Authors: Peters Daniel L. , Prowse Terry D. , Pietroniro Alain , Leconte Robert 
Published: November 2006

AbstractThis study conducted a systematic examination of the flood hydrology of the Peace‐Athabasca Delta (PAD), a complex and internationally important freshwater ecosystem located in northwestern Canada. Three distinct zones of floodwater origin within the PAD were discerned on the basis of the dominant hydrology and the topography represented by a digital‐elevation model (DEM): (1) perimeter Peace Delta, (2) perimeter Athabasca Delta, and (3) central delta lakes. Analysis of the satellite image and DEM‐derived flood maps of historically significant events, combined with field data of open‐water and ice‐influenced flood stages, revealed that ice‐jamming was the most effective and likely the only mechanism capable of recharging the highly elevated perimeter areas in the Athabasca and Peace Deltas. This supports the conclusion of previous studies that used hydrometric data external to the delta to infer inter‐delta flood conditions. By contrast, even the record open‐water flow to the Peace Delta could not generate overbank flow. Hydraulic simulation of the naturalized system (no dam & no weirs) suggests that overbanking of the lower Peace River would have been a rare occurrence without the effects of regulation. Both ice‐jam induced and open‐water high waters were found to recharge perched basins in the Athabasca Delta. Enlargement of the central delta lakes beyond the shoreline was determined to be an effective flood mechanism for filling low to mid‐elevation wetlands. Comparison of the observed and naturalized lake levels indicates that flow regulation of the Peace River and addition of the weirs on delta outflow channels has, depending on the year, led to an increase or a reduction in the annual maximum potential of inland flooding via lake expansion. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.