bluuebunny/crossref_metadata_2025_split huggingface dataset:
Säulenversuche zum Transportverhalten von Arzneimittelwirkstoffen in der wassergesättigten Zone
Authors: Mersmann Petra , Scheytt Traugott , Heberer Thomas 
Published: May 2003

AbstractEine Reihe von Arzneimittelrückständen wurde in den letzten Jahren im Oberflächenwasser, im Grundwasser und sogar im Trinkwasser nachgewiesen. Um detaillierte Informationen über das Transportverhalten von ausgewählten Arzneimittelwirkstoffen (Carbamazepin, Clofibrinsäure, Diclofenac, Ibuprofen, Propyphenazon) in der wassergesättigten Zone zu erhalten, wurden Säulenversuche mit gestörten Proben aus Grundwasserleitermaterial (Mittelsand) im Labormaßstab durchgeführt. Über einen Zeitraum von jeweils 10 Tagen wurde Versuchswasser, ein dem Grundwasserleitermaterial entsprechendes natürliches Grundwasser, mit den Wirkstoffen dotiert (10 μg/L), und die Konzentrationsänderungen am Säulenauslauf wurden beobachtet. Das Transportverhalten der untersuchten Medikamentenwirkstoffe war unter den gegebenen Bedingungen nicht von pH‐Wert, Temperatur, Sauerstoffgehalt und Grundwasserinhaltsstoffen abhängig. Mit einem Retardationsfaktor von 2.8 ist der Transport des Wirkstoffes Carbamazepin am deutlichsten gegenüber Lithium verzögert. Aufgrund des geringen C/C0‐Verhältnisses von 0.45 konnte für den Wirkstoff Ibuprofen der Retardationsfaktor lediglich abgeschätzt werden; demnach lag der Retardationsfaktor bei 4.0. Während Diclofenac (Rd = 2.6) und Propyphenazon (Rd = 2.0) langsamer als Lithium transportiert wurden, konnte für Clofibrinsäure ein Retardationsfaktor von 1.1 ermittelt werden.Das Transportverhalten der untersuchten Substanzen ist in unterschiedlichem Maß von Sorptions‐ und Abbauprozessen charakterisiert. Während Ibuprofen hauptsächlich abgebaut wird, ist der Abbau bei Carbamazepin und Diclofenac mit einem C/C0‐Verhältnis von 0.85 und 0.88 im aeroben Milieu allenfalls gering und bei Propyphenazon (C/C0 = 1.0) ist kein Abbau unter oxischen Bedingungen nachzuweisen. Clofibrinsäure war gänzlich unbeeinflusst von Sorptions‐ und Abbauprozessen.
Short‐term Sunlight Irradiation of Organic Matter Dissolved in Lake Water Increased its Susceptibility to Subsequent Biooxidation
Authors: Grzybowski Waldemar 
Published: May 2003

AbstractThe influence of daylong sunlight irradiation on the susceptibility of dissolved organic matter (DOM) to subsequent bacterial respiration was investigated in freshwater. The analyzed samples differed both in DOM content and photoreactivity (absorbance spectra). Filter‐sterilized samples (0.2 μm pore size filters) were exposed to daylong sunlight in a wide‐open vessel. After that, the samples and non‐irradiated blanks were inoculated with the native bacterial community and respiration was monitored for 20 h with 1 h frequency. In all of the analyzed samples, the exposure to sunlight resulted in increased respiration. The increase in respiration ranged from 17 to 54 %. The observed respiration changes were poorly correlated with changes in spectral characteristics of the samples caused by irradiation.
Niedermolekulare Verbindungen als Inhibitoren Cyclin‐abhängiger Kinasen
Authors: Huwe Axel , Mazitschek Ralph , Giannis Athanassios 
Published: May 2003

AbstractFür multizelluläre Organismen ist die Zellteilung (Mitose) eine grundlegende Voraussetzung. Erst durch die Fähigkeit einer Zelle, sich zu replizieren, können komplexe Zellverbände entstehen. Fehlregulationen in den Kontrollmechanismen des Zellzyklus führen zu einer übermäßigen Zellproliferation und sind die Ursache für Krebs. Die Schlüsselstellung der Cyclin‐abhängigen Kinasen (CDKs) und ihrer direkten Mitspieler sowie die Tatsache, dass bei vielen malignen Erkrankungen Komponenten dieser zentralen Schrittmacher des Zellzyklus defekt sind, hat ein großes Interesse für die Entwicklung von niedermolekularen CDK‐Inhibitoren geweckt. Im Folgenden wird ein Überblick über die verschiedenen Strukturklassen ATP‐kompetitiver Inhibitoren für CDKs gegeben, die mit der Absicht entwickelt wurden, maligne Erkrankungen zu bekämpfen. Der Aufsatz zeigt, wie weit die Entwicklung von selektiven CDK‐Inhibitoren ist und inwiefern sich die Erwartungen in solche Wirkstoffe bisher erfüllt haben.
Glossar zur Theoretischen Organischen Chemie
Authors: Zipse Hendrik , Schulz* Axel 
Published: May 2003

AbstractDieses Glossar enthält Definitionen und Erklärungen zu mehr als 450 Begriffen, die im fachübergreifenden Forschungs‐ und Publikationswesen auf dem Gebiet der Anwendung von modernen theoretischen Konzepten, der Computerchemie und graphentheoretischen Methoden zur Untersuchung von Struktur, Reaktivität, spektroskopischen und anderen physikalischen Eigenschaften von organischen, metallorganischen und Koordinationsverbindungen eine Rolle spielen. Das Ziel dieses Glossars ist die Bereitstellung eines Leitfadens für den Fachwortschatz, der in der Theoretischen Organischen Chemie verwendet wird. Des Weiteren soll es dazu beitragen, dass Inkonsistenzen und Zweideutigkeiten in der Bedeutung von Begriffen beseitigt werden.
Small Molecules as Inhibitors of Cyclin‐Dependent Kinases
Authors: Huwe Axel , Mazitschek Ralph , Giannis Athanassios 
Published: May 2003

AbstractCell division (mitosis) is one of the basic requirements for multicellular oranisms. The capability of a cell to replicate enables a complex assembly to be created. Faulty regulation of the control mechanism in the cell cycle leads to an excessive cell proliferation and is the cause of cancer. The key position of the cyclin‐dependent kinases (CDKs) and their direct partners, as well as the fact that the majority of malign illnesses show defects in at least one of these key players of the cell cycle, is of great interest for the development of low‐molecular‐weight CDK inhibitors. In this Review an overview of the different structural classes of ATP‐competitive inhibitors of CDKs are given, whose devlopment was aimed at battling cancer. The Review shows how far the development of selective CDK inhibitors has progressed and to what extent the expectations for such drugs have so far been fulfilled.
Electrical conductivity and thermal properties of poly(m‐aminophenyl acetic acid) and its copolymers with aniline
Authors: Rivas B. L. , Sánchez C. O. 
Published: May 2003

AbstractPoly(m‐aminophenyl acetic acid) was synthesized under different conditions from the respective monomer, using ammonium persulfate as oxidizing agent in both the presence and the absence of CuCl2 in HCl(aq). Moreover, the copolymers between aniline and m‐aminophenyl acetic acid were prepared at several feed mol ratios (f1) of aniline. Copper was introduced by the Batch method in the homo‐ and copolymers of different compositions. The polymers were characterized by FTIR and UV‐vis spectroscopy, elemental analysis, thermal analysis, and electrical conductivity. The thermal stability and the content of copper increased as the content of aniline was increased in the copolymers. Moreover, the copolymers showed a high thermal stability; at 400°C a weight loss < 10% was observed. The electrical conductivity was increased with a higher content of aniline in the copolymers, achieving semiconduction values. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1484–1492, 2003
Rheological and curing behavior of reactive blending. II. Natural rubber‐g‐poly(methyl methacrylate)–cassava starch
Authors: Nakason C. , Kaesaman A. , Rungvichaniwat A. , Eardrod K. , Kiatkamjonwong S. 
Published: May 2003

AbstractGraft copolymers of natural rubber (NR) and methyl methacrylate (MMA) were prepared using cumene hydroperoxide and tetraethylene pentamine as redox initiators via the semibatch emulsion polymerization technique. Various molar percentage ratios of NR/MMA were studied in the grafting reaction (i.e., 95/5, 90/10, 80/20, 70/30, and 60/40). The graft copolymer with a 70/30 molar ratio was selected and used to prepare rubber blends with cassava starch. The starch was used at levels of 0, 20, 40, and 60 phr. Another set of rubber blends was prepared for comparison purposes. The NR‐g‐poly(MMA) (PMMA, 75 phr) was blended with 25 phr of NR air dried sheets (ADS) and a given level of the cassava starch. We found that the Mooney viscosity, shear stress, and shear viscosity increased with an increasing concentration of cassava starch. This may be attributed to the chemical interactions between the polar groups of the NR‐g‐PMMA and the cassava starch. The blends were later compounded using a compounding formulation according to ASTM D 3184‐89. A similar short delay onset of vulcanization (i.e., approximately 1 min) was observed for the whole set of compounds under study. However, different curing characteristics were observed for the blends of NR‐g‐PMMA–cassava starch and NR‐g‐PMMA–ADS–cassava starch. The NR‐g‐PMMA–cassava starch compounds exhibited two‐stage curing characteristics. The curing curve had a slight reversion at a testing time of approximately 8 min. The shear modulus then abruptly increased with an increasing testing time in the range of 20–60 min. The curing curves for NR‐g‐PMMA–ADS–cassava starch blends exhibited a single curing stage with a shear modulus that increased slightly with the testing time was increased from 20 to 60 min. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1453–1463, 2003
Hydrogels based on poly(ethylene oxide) and poly(tetramethylene oxide) or poly(dimethyl siloxane). II. Physical properties and bacterial adhesion
Authors: Park Jae Hyung , Bae You Han 
Published: May 2003

AbstractTo investigate the effects of polymer chemistry and topology on physical properties and bacterial adhesion, various hydrogels composed of short hydrophilic [poly(ethylene oxide) (PEO)] and hydrophobic blocks were synthesized by polycondensation reactions. Differential scanning calorimetry and X‐ray diffraction analysis confirmed that all of the hydrogels were strongly phase‐separated due to incompatibility between PEO and hydrophobic blocks such as poly(tetramethylene oxide) (PTMO) and poly(dimethyl siloxane) (PDMS). The crystallization of PEO in the hydrogels was enhanced by the incorporation of longer PEO chains, the adoption of PDMS as a hydrophobic block, and the grafting of monomethoxy poly(ethylene oxide) (MPEO). Compared to Pellethane, the control polymer, the hydrogels exhibited higher Young's moduli and elongations at break, which was attributed to the crystalline domains of PEO and the flexible characteristics of the hydrophobic blocks. The mechanical properties of the hydrogels, however, significantly deteriorated when they were hydrated in distilled water; this was primarily ascribed to the disappearance of PEO crystallity. The water capacity of hydrogels at 37°C in phosphate‐buffered saline (PBS) (pH = 7.4) was dominantly dependant on PEO content, which also influenced the thermonegative swelling behavior. From the bacterial adhesion tests, it was evident that both S. epidermidis and E. coli adhered to Pellethane much greater than to the hydrogels, regardless of the preadsorption of albumin. Better resistance to bacterial adhesion was observed in hydrogels with longer PEO chains, with PTMO as a hydrophobic block, and with MPEO grafts. The least bacterial adhesion for both species was achieved on MPEO2k–PTMO, a hydrogel with MPEO grafts. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1505–1514, 2003
Fluorinated epoxides as surface modifying agents of UV‐curable systems
Authors: Sangermano M. , Bongiovanni R. , Malucelli G. , Priola A. , Pollicino A. , Recca A. 
Published: May 2003

AbstractTwo commercially available epoxy‐fluorinated monomers, 3‐(perfluorooctyl)‐1,2‐propenoxide and 3‐(1H, 1H, 9H‐hexadecafluorononyloxyl)‐1,2 propenoxide, were used as modifying additives for UV curable systems. These two fluorinated monomers were mixed, in small amounts (less than 1% w/w) with a hydrogenated epoxy monomer 1,4‐cyclohexanedimethanol‐diglycidyl ether. The mixtures were coated on glass substrate and UV‐cured, giving rise to transparent films. Notwithstanding their very low concentrations, the fluorinated monomers caused a change in the surface properties of the films, without changing their curing conditions and their bulk properties. The air side of the coatings became highly hydrophobic, while the substrate side was unmodified. As shown by XPS measurements, the fluorinated monomers were able to concentrate selectively on the air side of the films, forming a fluorinated layer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1524–1529, 2003
Soy protein–lignosulphonate plastics strengthened with cellulose
Authors: Huang Jin , Zhang Lina , Wang Xiaohua 
Published: May 2003

AbstractA series of biodegradable plastics from soy protein and lignosulphonate (SL) were strengthened with cellulose powder (CP) by melt blending and compression molding. The effects on the morphology and properties of the blends of introducing CP were investigated by wide‐angle X‐ray diffraction, differential scanning calorimetry, dynamic mechanical thermal analysis, scanning electron microscopy, and tests of tensile and water absorption. It is worth noting that introducing CP obviously improved the mechanical properties and water resistivity of composite plastics. With an increase in CP content, the tensile strength and Young's modulus of the blend materials increased. The experimental results indicate that a certain degree of miscibility between SL and CP and a strong interaction among various molecules of the components, resulting in strengthened materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1685–1689, 2003
Solvent‐induced modifications in polyester yarns. II. Structural and thermal behavior
Authors: Chidambaram D. , Venkatraj R. , Manisankar P. 
Published: May 2003

AbstractThe structural and thermal behaviors of polyester yarns treated with trichloroacetic acid–chloroform (TCAC) mixture were investigated by differential scanning calorimetric analysis (DSC), wide‐angle X‐ray scattering (WAXS), infrared spectroscopy (IR), and scanning electron microscopy (SEM). The effects of TCAC treatment on original fine filament (FFP) and microdenier (MDP) polyester yarns and on heat‐set polyester yarns were studied. It was found that the glass transition temperature of TCAC‐treated polyester yarns decreases with an increase in treatment concentration due to the plasticization effect, which is remarkable even at lower treatment concentration. The TCAC treatment on polyester yarns resulted in the formation of new crystallites in the extended noncrystalline domains of PET as well as growth and perfection of these new crystallites and the preexisting crystals. Further, the DSC thermograms revealed that TCAC treatment with 3% concentration could be able to overcome the structural changes in PET produced by heat setting at 180°C. The substantial changes in noncrystalline and crystalline domains observed were related to the mechanical properties of yarns. From the WAXS studies, an increase in crystal size and lateral order of TCAC‐treated polyester yarns was noted. The most distinct changes brought about by TCAC treatment include overall orientation determined by the trans–gauche ratio from IR measurements. The removal of oligomers and smoothening out of the fiber surface by TCAC treatment were observed from SEM studies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1555–1566, 2003
Mechanical, rheological, thermal, and morphological properties of blends based on poly(propylene)/poly(propylene‐co‐1‐octene)/poly(ethylene‐co‐1‐octene)
Authors: Lovisi Humberto , Silva Ana Lúcia N. , de Santa Maria Luiz Claudio , Rocha Marisa C. G. , Bretas Rosário E. S. , Farah Marcelo , Coutinho Fernanda M. B. 
Published: May 2003

AbstractThe effect of addition of propylene copolymer, produced by metallocene catalysts, on the mechanical, rheological, and morphological properties of blends based on poly(propylene) (PP) and ethylene–1‐octene copolymer (EOC) was evaluated. It was observed that the addition of 2 wt % propylene–1‐octene copolymer (POC) improved the impact strength of the EOC/PP blends. The rheological analysis indicated that the addition of propylene copolymer produced materials with improved processability. Thermal and morphological analysis showed that the POC acts as a compatibilizer on the EOC/PP blends. © 2003 Wiley Periodicals, J Appl Polym Sci 89: 1690–1695, 2003
Antielectrostatic poly(ether ester) block copolymer of poly(ethylene terephthalate‐co‐isophthalate)–poly(ethylene glycol)
Authors: Li Xin , Liu Ruitao , Zhong Leilan , Gu Lixia 
Published: May 2003

AbstractPoly(ethylene terephthalate) (PET) fiber has a low moisture regain, which allows it to easily gather static charges, and many investigations have been carried out on this problem. In this study, a series of poly(ethylene terephthalate‐co‐isophthalate) (PEIT)–poly(ethylene glycol) (PEG) block copolymers were prepared by the incorporation of isophthalic acid (IPA) during esterification and PEG during condensation. PEG afforded PET with an increased moisture affinity, which in turn, promoted the leakage of static charges. However, PET also then became easier to crystallize, even at room temperature, which led to decreased antistatic properties and increased manufacturing inconveniences. IPA was, therefore, used to reduce the crystallinity of the copolymers and, at the same time, make their crystal structure looser for increased water absorption. Moreover, PET fibers with incorporated IPA and PEG showed good dyeability. In this article, the structural characterization of the copolymers and antistatic and mechanical properties of the resulting fibers are discussed. At 4 wt % IPA, the fiber containing 1 mol % PEG with a molecular weight of 1000 considerably improved antistatic properties and other properties. In addition, the use of PEIT–PEG as an antistatic agent blended with PET or modified PET fibers also benefitted the antistatic properties. Moreover, PEIT–PEG could be used with another antistatic agent to produce fibers with a low volume resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1696–1701, 2003
Dynamic swelling behavior of pH‐sensitive anionic hydrogels used for protein delivery
Authors: Kim Bumsang , La Flamme Kristen , Peppas Nicholas A. 
Published: May 2003

AbstractThere have been many attempts to use anionic hydrogels as oral protein delivery carriers because of their pH‐responsive swelling behavior. The dynamic swelling behavior of poly(methacrylic acid‐co‐methacryloxyethyl glucoside) and poly(methacrylic acid‐g‐ethylene glycol) hydrogels was investigated to determine the mechanism of water transport through these anionic hydrogels. The exponential relation Mt/M∞ = ktn (where Mt is the mass of water absorbed at time t and M∞ is the mass of water absorbed at equilibrium) was used to calculate the exponent (n) describing the Fickian or non‐Fickian behavior of swelling polymer networks. The mechanism of water transport through these gels was significantly affected by the pH of the swelling medium. The mechanism of water transport became more relaxation‐controlled in a swelling medium of pH 7.0, which was higher than pKa of the gels. The experimental results of the time‐dependent swelling behaviors of the gels were analyzed with several mathematical models. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1606–1613, 2003
Preparation and characterization of organic films by the electrooxidation of a thiophene imine derivative
Authors: Diaz F. R. , del Valle M. A. , Brovelli F. , Tagle L. H. , Bernede J. C. 
Published: May 2003

Abstract2,2′‐Dithienylimine was synthesized and electrochemically oxidized. The polymer was obtained on platinum or glass electrodes coated with tin oxide. The films were characterized with scanning electron microscopy, microprobes, and X‐ray photoelectron spectroscopy. The coverage efficiency of the films was very high, but there were some morphological defects on the surfaces. Furthermore, there was some oxygen contamination not only on the surface but also in the bulk of the films. The nucleation and growth mechanisms responded to tridimensional instantaneous nucleation and bidimensional progressive nucleation contributions, which were consistent with the morphologies determined by scanning electron microscopy. The current–voltage characteristics exhibited a turn‐on voltage of 5–6 V, which depended on the film thickness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1614–1621, 2003
Photoinitiated grafting of glycidyl methacrylate and methacrylic acid on ground tire rubber
Authors: Fuhrmann I. , Karger‐Kocsis J. 
Published: May 2003

AbstractGround tire rubber (GTR) films and GTR particles were surface‐functionalized by glycidyl methacrylate and methacrylic acid through photoinitiated grafting. The grafting yield of GTR films was determined by Fourier transform infrared spectroscopy with attenuated total reflection (FTIR‐ATR). For the calibration of the FTIR‐ATR data, X‐ray photoelectron spectroscopy was used. The presence of epoxy and carboxyl groups on the GTR surface was demonstrated by contact‐angle measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1622–1630, 2003
Modification of the Structure of 4, 6‐Disubstituted 2‐(4‐Alkyl‐1‐piperazinyl)pyridines: Synthesis and Their 5‐HT2A Receptor Activity
Authors: Paluchowska Maria H. , Bojarski Andrzej J. , Bugno Ryszard , Charakchieva‐Minol Sijka , Wesołowska Anna 
Published: May 2003

AbstractStructure‐activity relationship studies of a series of novel 4, 6‐disubstituted 2‐(1‐piperazinyl)pyridines were conducted to revise our model of serotonin 5‐HT2A receptor antagonist. Target compounds were synthesized using the benzotriazole‐assisted Katritzky method. The majority of those compounds were found to be selective 5‐HT2A/5‐HT1A receptor ligands, though less potent than their previously described pyrimidine counterparts. In particular, the three compounds 6—8 showed the highest 5‐HT2A receptor affinity (Ki = 34—78 nM) and were classified as 5‐HT2A antagonists in in vivo experiments. The influence of the structural modifications on the in vitro results was discussed; however, the elucidation of the role of the central core system requires further studies.
Design and Synthesis of Some Substituted 1H‐Pyrazolyl‐oxazolidines or 1H‐Pyrazolyl‐thiazolidines as Anti‐inflammatory‐Antimicrobial Agents
Authors: Bekhit Adnan A. , Fahmy Hesham T. Y. 
Published: May 2003

AbstractFour series of 1H‐pyrazole derivatives have been synthesized. The first series was synthesized starting with the reaction of 3‐(5‐bromo‐2‐thienyl)‐1‐phenyl‐1H‐pyrazole‐4‐carboxaldehyde1with L‐serine, L‐cysteine, or L‐penicillamine, followed byN‐protection using (Boc)2O to provide compounds2. The latter compounds could beN‐deprotected by 4N HCl/dioxane to afford the second series3orreactedwith NH4OH in the presence of DCC/HOBt to give the corresponding amides4followed byN‐deprotection giving rise to compounds5. The newly synthesized compounds were evaluated for their anti‐inflammatory‐antimicrobial activities. In addition, the ulcerogenic and acute toxicity profiles were determined. Compound5b(2RS, 4R)‐2‐[3‐(5‐bromo‐2‐thienyl)‐1‐phenyl‐1H‐pyrazol‐4‐yl]‐5‐methylthiazolidine‐4‐carboxamide, proved to be the most active anti‐inflammatory‐antimicrobial agent in the present study with a good safety margine and no ulcerogenic effect.