bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanoporous Lanthanide–Copper(II) Coordination Polymers: Syntheses and Crystal Structures of [{M2(Cu3(iminodiacetate)6)}⋅8 H2O]n (M=La, Nd, Eu)
Authors: Ren Yan‐Ping , Long La‐Sheng , Mao Bing‐Wei , Yuan You‐Zhu , Huang Rong‐Bin , Zheng Lan‐Sun
Published: May 2003

In der Zuschrift „Nanoporous Lanthanide–Copper(II) Coordination Polymers: Syntheses and Crystal Structures of [{M2(Cu3(iminodiacetate)6)}⋅8 H2O]n (M=La, Nd, Eu)“ von Y.‐P. Ren, L.‐S. Long, et al. (1) vergaßen die Autoren, wichtige Veröffentlichungen zu zitieren: „Synthesis, Crystal Structure and Magnetic Properties of a Series of Polymeric Lanthanoid–Copper Complexes [Ln2Cu3{O(CH2CO2)2}6]⋅n H2O (Ln=La, Nd, n=9; Ln=Er, n=6)“ (J. G. Mao, J. S. Huang, J. F. Ma, J. Z. Ni, Trans. Met. Chem. 1997, 22, 277–280), „Synthesis and Crystal Structure of a Novel Lanthanide–Copper Mixed Metal Complex: Gd2Cu3{O(CH2COO)2}6⋅9 H2O“ (J. G. Mao, L. Song, X. Y. Huang, J. S. Huang, Polyhedron 1997, 16, 963–966), „Synthesis and Structural Characterization of a Novel Polymeric Gadolinium(III)–Copper(II) Complex of Iminodiacetic Acid” (J. G. Mao, L. Song, J. S. Huang, J. Chem. Crystallogr. 1998, 28, 475–479) und „Synthesis and Crystal Structure of a New Praseodymiun(III)–Copper(II) Polymeric Complex: [Pr2(Cu3(L1)6)n] (H2L1=NH{CH2COOH}2)“ (J. G. Mao, L Song, J. S. Huang, Chinese J. Struct. Chem. 1999, 18, 4–8). Die Autoren entschuldigen sich für diese Nachlässigkeit und danken Qinde Liu von der Queen's University, Kanada, sowie Prof. J. G. Mao, Fuzhou, China, für die Hinweise.
Small Molecules as Inhibitors of Cyclin‐Dependent Kinases
Authors: Huwe Axel , Mazitschek Ralph , Giannis Athanassios
Published: May 2003

Cell 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.
Cover Picture: An Unusual Dynamic Fe‐Hg‐Pd Cluster with a Palladium(0) Fragment Stabilized by d10–d10 Heterometallic Bonding (Angew. Chem. Int. Ed. 19/2003)
Authors: Schuh Walter , Braunstein Pierre , Bénard Marc , Rohmer Marie‐Madeleine , Welter Richard
Published: May 2003

What goes around comes around. The cover picture describes how a Pd center undergoes an oscillating motion along the Fe‐Hg‐Fe metal chain of a cluster that exhibits helically arranged diphenylphosphanylmethane ligands. The Pd0 fragment was “captured” by a trimetallaphosphane that can easily adapt its conformation through rotation about a HgFe bond. For more details of this unusual cluster, which exhibits an unprecedented PdHg d10–d10 interaction, see the Communication by P. Braunstein et al. on page 2161ff.
Nanoporous Lanthanide–Copper(II) Coordination Polymers: Syntheses and Crystal Structures of [{M2(Cu3(iminodiacetate)6)}⋅8 H2O]n (M=La, Nd, Eu)
Authors: Ren Yan‐Ping , Long La‐Sheng , Mao Bing‐Wei , Yuan You‐Zhu , Huang Rong‐Bin , Zheng Lan‐Sun
Published: May 2003

In the Communication “Nanoporous Lanthanide–Copper(II) Coordination Polymers: Syntheses and Crystal Structures of [{M2(Cu3(iminodiacetate)6)}⋅8 H2O]n (M=La, Nd, Eu)” by Y.‐P. Ren, L.‐S. Long, et al. (1) the authors missed important references: “Synthesis, Crystal Structure and Magnetic Properties of a Series of Polymeric Lanthanoid–Copper Complexes [Ln2Cu3{O(CH2CO2)2}6]⋅n H2O (Ln=La, Nd, n=9; Ln=Er, n=6)” (J. G. Mao, J. S. Huang, J. F. Ma, J. Z. Ni, Trans. Met. Chem. 1997, 22, 277–280), “Synthesis and Crystal Structure of a Novel Lanthanide–Copper Mixed Metal Complex: Gd2Cu3{O(CH2COO)2}6⋅9 H2O” (J. G. Mao, L. Song, X. Y. Huang, J. S. Huang, Polyhedron 1997, 16, 963–966), “Synthesis and Structural Characterization of a Novel Polymeric Gadolinium(III)–Copper(II) Complex of Iminodiacetic Acid” (J. G. Mao, L. Song, J. S. Huang, J. Chem. Crystallogr. 1998, 28, 475–479), and “Synthesis and Crystal Structure of a New Praseodymiun(III)–Copper(II) Polymeric Complex: [Pr2(Cu3(L1)6)n] (H2L1=NH{CH2COOH}2)” (J. G. Mao, L Song, J. S. Huang, Chinese J. Struct. Chem. 1999, 18, 4–8). The authors apologize for this oversight and thank Qinde Liu of Queen's University, Canada, and Prof. J. G. Mao, Fuzhou, China, for bringing it to their attention.
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

Poly(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

Graft 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

To 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

Two 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

A 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

The 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

The 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

Poly(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

There 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

2,2′‐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

Ground 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

Structure‐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

Four 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.
Activities of Prenylphenol Derivatives from Fruitbodies of Albatrellus spp. on the Human and Rat Vanilloid Receptor 1 (VR1) and Characterisation of the Novel Natural Product, Confluentin
Authors: Hellwig Veronika , Nopper Reilinde , Mauler Frank , Freitag Joachim , Ji‐Kai Liu , Zhi‐Hui Ding , Stadler Marc
Published: May 2003

Several prenylphenols from basidiocarps of European and Chinese Albatrellus spp., namely grifolin (1), neogrifolin (2), confluentin (3), scutigeral (4), and albaconol (5) were investigated concerning their activities in test models for vanilloid receptor modulation. The isolation of these compounds from A. confluens and structure elucidation of the novel natural product confluentin (3) are described. The effects of scutigeral and neogrifolin on vanilloid receptors were studied by means of electrophysiological methodology on rat dorsal root ganglion neurons as well as on recombinant cell lines expressing the rat VR1 receptor. Concurrently, the effects of compounds 1—5 on a reporter cell line expressing the human vanilloid receptor VR1 were measured. In contrast to previous studies reported in the literature, the results of these investigations suggest that fungal prenylphenols act as weak antagonists (activity in the μM range), rather than exhibiting agonistic activities.
The Structure and Ion Channel Activity of 6‐Benzylamino‐3‐hydroxyhexa‐cyclo[6.5.0.03, 7.04, 12.05, 10.09, 13]tridecane
Authors: Malan Sarel F. , Dyason Karin , Wagenaar Bianca , van der Walt J. Jurgens , Van der Schyf Cornelis J.
Published: May 2003

A novel compound, 6‐benzylamino‐3‐hydroxyhexacyclo [6.5.0.03, 7.04, 12.05, 10.09, 13]‐tridecane, was synthesized as part of an ongoing study to explore the ion channel activity of polycyclic cage amines. The known polycyclic calcium channel antagonist, 8‐benzylamino‐8, 11‐oxapentacyclo [5.4.0.02, 6.03, 10.05, 9]undecane (NGP 1‐01) served as the lead compound and as a positive control for channel activity. The title compound inhibited calcium currents at test concentrations of 10 μM at depolarized membrane potentials (in the potential range where the L‐type calcium channel inactivates). At the test concentrations modulating effects were also observed for sodium and the delayed rectifier potassium currents. Due to its activity at both Ca2+ and Na+ channels, this compound may offer utility as a cardiovascular and/or neuroprotecting agent.
Synthesis and Pharmacological Investigations of Some 4‐Hydroxycoumarin Derivatives
Authors: Manolov Ilia , Danchev Nicolay D.
Published: May 2003

The synthesis of ten coumarin derivatives of 4‐hydroxycoumarin and various unsaturated ketones and aldehydes is described. The structures of the synthesized compounds were confirmed by IR, 1H‐NMR, and mass‐spectral data. Acute toxicity studies of the compounds were performed on mice by oral and intraperitoneal administration. A comparative pharmacological study of the in vivo anticoagulant effects of the derivatives with respect to warfarin, showed that the compounds have anticoagulant activity. Compounds 4‐hydroxy‐3‐[1‐phenyl‐2‐(4′‐chlorobenzoyl)ethyl]‐2H‐1‐benzopyran‐2‐one 2b, 4‐hydroxy‐3‐[1‐(4‐fluorophenyl)‐3‐oxobutyl]‐2H‐1‐benzopyran‐2‐one 3a, and 3, 3′‐p‐bromobenzylidene‐bis‐(4‐hydroxy‐2H‐1‐benzopyran‐2‐one) 4b showed slight acute toxicity and a greater anticoagulant effect than warfarin.
Substituted Quinazolines, Part 2. Synthesis and In‐Vitro Anticancer Evaluation of New 2‐Substituted Mercapto‐3H‐quinazoline Analogs
Authors: Khalil Ashraf A. , Hamide Sami G. Abdel , Al‐Obaid Abdulrahman M. , El‐Subbagh Hussein I.
Published: May 2003

A new series of 2‐substituted mercapto‐3H‐quinozolines bearing 6‐iodo and 2‐heteroarylthio functions was synthesized and screened for their in vitro antitumor activity. Eighteen compounds were identified as active anticancer agents. N′‐[(3‐Benzyl‐4‐oxo‐6‐iodo‐3H‐quinazoline‐2‐yl)thioacetyl]‐N3‐ethylthiosemicarbazide (10), N‐benzoyl‐N′‐[2‐(3‐benzyl‐4‐oxo‐6‐iodo‐3H‐quinozolin‐2‐yl)thioacetyl]hydrazine (12), and 2‐[(3, 6‐dioxo‐pyridazin‐4‐yl)thio]‐3‐benzyl‐4‐oxo‐6‐iodo‐3H‐quinazoline (20) proved to be the most active members in this study. They showed MG‐MID, GI50 values of 12.8, 11.3, and 13.8 μM, respectively. The detailed synthesis and biological screening data are reported.
A Test for the Number of Coupled Spins I=1/2 in Magic‐Angle‐Spinning Solids: Zero‐Quantum Recoupling of Multiple‐Quantum Coherences
Authors: Hughes Colan E. , Schmedt auf der Günne Jörn , Levitt Malcolm H.
Published: May 2003

Current methodologies for estimating the number of coupled spins I=1/2 in solids are based upon the maximum multiple‐quantum order that can be observed. This strategy establishes a clear lower bound on the number of coupled spins I=1/2. However, it is difficult to ascertain the exact number of coupled spins, since the absence of a peak could be due either to the limited size of the spin system or to the experimental difficulty of exciting high‐quantum orders and recovering those coherences into detectable signals. Herein, a supplementary test is proposed that allows one to determine whether a given coherence has the highest possible order in the spin system. The sample is subjected to magic‐angle spinning and the behaviour of the coherence under a rotor‐synchronised spin‐echo sequence is compared to its behaviour under a zero‐quantum recoupling sequence. A similar decay of the coherence in these two experiments is strong evidence for the coherence order being the maximum possible. We propose applications to biomolecular solid‐state NMR spectroscopy.
Adsorption of CO2 and Coadsorption of H and CO2 on Potassium‐Promoted Cu(115)
Authors: Onsgaard Jens , Hoffmann Søren V. , Møller Palle , Godowski P. Jan , Wagner Jacob B. , Paolucci Giorgio , Baraldi Alessandro , Comelli Giovanni , Groso Amela
Published: May 2003

The influence of potassium, in the submonolayer regime, on the adsorption and coadsorption of CO2 and H on a stepped copper surface, Cu(115), has been studied by photoelectron spectroscopy, temperature‐programmed desorption, and work‐function measurements. Based on the fast recording of C 1s and O 1s core‐level spectra, the uptake of CO2 on K/Cu(115) surfaces at 120 K has been followed in real time, and the different reaction products have been identified. The K 2p3/2 peak exhibits a chemical shift of −0.4 eV with CO2 saturation, the C 1s peaks of the CO3 and the CO species show shifts of −0.8 and −0.5 eV, respectively, and the C 1s peak of the physisorbed CO2 exhibits no shift. The effects of gradually heating the CO2/K/Cu(115) surface include the desorption of physisorbed CO2 at 143 K; the desorption of CO at 193 K; the ordering of the CO3 species, and subsequently the dissociation of the carbonate with desorption at 520–700 K. Formate, HCOO−, was synthesized by the coadsorption of H and CO2 on the K/Cu(115) surface at 125 K. Formate formed exclusively for potassium coverages of less than 0.4 monolayer, whereas both formate and carbonate were formed at higher coverages. The desorption of formate‐derived CO2 took place in the temperature range 410–425 K and carbonate‐derived CO2 desorbed at 645–660 K, depending on the potassium coverage.
Studies on Intra‐Supramolecular and Intermolecular Electron‐Transfer Processes between Zinc Naphthalocyanine and Imidazole‐Appended Fullerene
Authors: El‐Khouly Mohamed E. , Rogers Lisa M. , Zandler Melvin E. , Suresh Gadde , Fujitsuka Mamoru , Ito Osamu , D'Souza Francis
Published: May 2003

Spectroscopic, computational, redox, and photochemical behavior of a self‐assembled donor‐acceptor dyad formed by axial coordination of zinc naphthalocyanine, ZnNc, and fulleropyrrolidine bearing an imidazole coordinating ligand (2‐(4′‐imidazolylphenyl)fulleropyrrolidine, C60Im) was investigated in noncoordinating solvents, toluene and o‐dichlorobenzene, and the results were compared to the intermolecular electron transfer processes in a coordinating solvent, benzonitrile. The optical absorption and ab initio B3 LYP/3–21G(*) computational studies revealed self‐assembled supramolecular 1:1 dyad formation between the ZnNc and C60Im entities. In the optimized structure, the HOMO was found to be entirely located on the ZnNc entity while the LUMO was found to be entirely on the fullerene entity. Cyclic voltammetry studies of the dyad exhibited a total of seven one‐electron redox processes in o‐dichlorobenzene, with 0.1 M tetrabutylammonium perchlorate. The excited‐state electron‐transfer processes were monitored by both optical‐emission and transient‐absorption techniques. Direct evidence for the radical‐ion‐pair (C60Im.−:ZnNc.+) formation was obtained from picosecond transient‐absorption spectral studies, which indicated charge separation from the singlet‐excited ZnNc to the C60Im moiety. The calculated rates of charge separation and charge recombination were 1.4×1010 s−1 and 5.3×107 s−1 in toluene and 8.9×109 s−1 and 9.2×107 s−1 in o‐dichlorobenzene, respectively. In benzonitrile, intermolecular electron transfer from the excited triplet state of ZnNc to C60Im occurs and the second‐order rate constant (kqtriplet) for this quenching process was 5.3×108 M−1 s−1.
Femtochemistry of trans‐Azomethane: A Combined Experimental and Theoretical Study
Authors: Diau Eric W.‐G. , Zewail Ahmed H.
Published: May 2003

The dissociation dynamics of trans‐azomethane upon excitation to the S1(n,π*) state with a total energy of 93 kcal mol−1 is investigated using femtosecond‐resolved mass spectrometry in a molecular beam. The transient signal shows an opposite pump–probe excitation feature for the UV (307 nm) and the visible (615 nm) pulses at the perpendicular polarization in comparison with the signal obtained at the parallel polarization: The one‐photon symmetry‐forbidden process excited by the UV pulse is dominant at the perpendicular polarization, whereas the two‐photon symmetry‐allowed process initiated by the visible pulse prevails at the parallel polarization. At the perpendicular polarization, we found that the two CN bonds of the molecule break in a stepwise manner, that is, the first CN bond breaks in ≈70 fs followed by the second one in ≈100 fs, with the intermediate characterized. At the parallel polarization, the first CN bond cleavage was found to occur in 100 fs with the intensity of the symmetry‐allowed transition being one order of magnitude greater than the intensity of the symmetry‐forbidden transition at the perpendicular polarization. Theoretical calculations using time‐dependent density functional theory (TDDFT) and the complete active space self‐consistent field (CASSCF) method have been carried out to characterize the potential energy surface for the ground state, the low‐lying excited states, and the cationic ground state at various levels of theory. Combining the experimental and theoretical results, we identified the elementary steps in the mechanism: The initial driving force of the ultrafast bond‐breaking process of trans‐azomethane (at the perpendicular polarization) is due to the CNNC torsional motion initiated by the vibronic coupling through an intensity‐borrowing mechanism for the symmetry‐forbidden n–π* transition. Following this torsional motion and the associated molecular symmetry breaking, an S0/S1 conical intersection (CI) can be reached at a torsional angle of 93.1° (predicted at the CASSCF(8,7)/cc‐pVDZ level of theory). Funneling through the S0/S1 CI could activate the asymmetric CN stretching motion, which is the key motion for the consecutive CN bond breakages on the femtosecond time scale.
Quantum Control of Gas‐Phase and Liquid‐Phase Femtochemistry
Authors: Brixner Tobias , Gerber Gustav
Published: May 2003

Active control of chemical reactions on a microscopic (molecular) level, that is, the selective breaking or making of chemical bonds, is an old dream. However, conventional control agents used in chemical synthesis are macroscopic variables such as temperature, pressure or concentration, which gives no direct access to the quantum‐mechanical reaction pathway. In quantum control, by contrast, molecular dynamics are guided with specifically designed light fields. Thus it is possible to efficiently and selectively reach user‐defined reaction channels. In the last years, experimental techniques were developed by which many breakthroughs in this field were achieved. Femtosecond laser pulses are manipulated in so‐called pulse shapers to generate electric field profiles which are specifically adapted to a given quantum system and control objective. The search for optimal fields is guided by an automated learning loop, which employs direct feedback from experimental output. Thereby quantum control over gas‐phase as well as liquid‐phase femtochemical processes has become possible. In this review, we first discuss the theoretical and experimental background for many of the recent experiments treated in the literature. Examples from our own research are then used to illustrate several fundamental and practical aspects in gas‐phase as well as liquid‐phase quantum control. Some additional technological applications and developments are also described, such as the automated optimization of the output from commercial femtosecond laser systems, or the control over the polarization state of light on an ultrashort timescale. The increasing number of successful implementations of adaptive learning techniques points at the great versatility of computer‐guided optimization methods. The general approach to active control of light–matter interaction has also applications in many other areas of modern physics and related disciplines.
Cover Picture: Electrosurface Phenomena at Polymer Films for Biosensor Applications (ChemPhysChem 5/2003)
Authors: Zimmermann Ralf , Birkert Oliver , Gauglitz Günter , Werner Carsten
Published: May 2003

The cover picture summarizes the principle of the Microslit Electrokinetic Set‐Up, which has been applied for the combined determination of zeta potential and surface conductivity of polymer films for biosensor applications. The method is based on streaming potential and streaming current measurements across rectangular channels formed by two planar sample carriers (20 mm×10 mm) at varied distances in the range of 1 to 60 μm. Combined determination of zeta potential and surface conductivity was advantageous for the analysis of interfacial charge distributions at swelling and reorganizing solid surfaces. The high sensitivity of the surface conductivity for structural variations of layered substrates may even allow the use of this parameter for detection in future biosensors. Find out more in the article by Zimmermann et al. on pages 509–514.
Promising effects of adenosine triphosphate infusion on nutritional status and quality of life in advanced non‐small‐cell lung cancer: a randomized clinical trial
Authors: Dagnelie Pieter C. , Agteresch Hendrik J.
Published: May 2003

Previous studies animal and phase I/II studies suggested that regular ATP infusions may inhibit loss of body weight in cancer. In this report, we summarize data from a recent trial (Agteresch et al. [2000a] J Natl Cancer Inst 92:321–328; Agteresch et al. [2000b] Eur J Clin Pbarmacol 56:49–55) in 58 patients with non‐small‐cell lung cancer, stage IIIB or IV. Patients were randomized to receive either 10 intravenous 30‐h ATP infusions every 2 to 4 weeks (n=28), or no ATP (n=30). Body weight, body composition (anthropometry, isotope dilution), muscle strength (elbow flexor and knee extensor), energy intake (3‐day food record), and quality of life (validated Rotterdam Symptom Checklist, RSCL) were assessed at 4‐week intervals during 28 weeks. Between‐group differences were tested for statistical significance (P < 0.05) by repeated‐measures analysis of covariance. Over the 28‐week follow‐up period, the control group showed progressive deterioration in body weight, fat mass, body cell mass, arm muscle area, and elbow flexor and knee extensor muscle strength. In contrast, in the ATP group, complete stabilization of these parameters was observed. Energy intake decreased significantly in the control group, but remained stable in the ATP group. ATP also inhibited the progressive rise in plasma values of C‐reactive protein seen in control patients. All mentioned between‐group differences were statistically significant. Significant favorable effects of ATP were also found for different domains of quality of life as assessed by the RSCL, i.e., physical, functional, and overall quality of life, whereas no significant effect of ATP on the psychological subscale of the RSCL was detected. In conclusion, ATP is the first agent that has been shown, in a randomized clinical trial, to counteract the loss of both metabolically active tissues (skeletal muscle and body cell mass) and fat mass, and improve muscle strength and quality of life (including functional status and fatigue) in patients with advanced cancer. Maintenance of energy intake and inhibition of chronic inflammation are likely to contribute to these effects of ATP. These results warrant further studies in patients with cancer and inflammatory diseases. Drug Dev. Res. 59:146–151, 2003. © 2003 Wiley‐Liss, Inc.
Modulation of the A3 adenosine receptor by low agonist concentration induces antitumor and myelostimulatory effects
Authors: Merimsky Ofer , Bar‐Yehuda Sara , Madi Lea , Fishman Pnina
Published: May 2003

The A3 adenosine receptor (A3AR) agonists IB‐MECA and Cl‐IB‐MECA act as anticancer agents by inhibiting the growth of melanoma and colon carcinoma cells both in vitro and in vivo. The A3AR is highly expressed in these tumor cells and upon agonist binding receptor internalization and recycling occurs. The downstream signaling pathways that follow these events include a decrease in the expression level of protein kinase A (PKA) and protein kinase B/Akt (PKB/Akt) leading to the deregulation of the Wnt and the NF‐κB signaling pathways. Interestingly, IB‐MECA and Cl‐IB‐MECA generate the opposite, beneficial effect on myeloid cells. These agonists induce the production of granulocyte colony‐stimulating factor (G‐CSF) by murine splenocytes. The molecular mechanisms underlying the events prior to G‐CSF production include the upregulation of NF‐κB and the upstream kinases phosphoinositide 3‐kinase (PI3K), PKB/Akt, and IKK. In addition, a myeloprotective effect is noted upon administration of IB‐MECA and Cl‐IB‐MECA to chemotherapy‐treated mice. This was expressed by accelerated recovery of white blood cells and neutrophil counts in cyclophosphamide‐treated mice following agonist administration. Taken together, activation of the A3AR on tumor and normal cells generates opposing responses: in tumor cells, NF‐κB expression level decreases, resulting in tumor growth inhibition, while in normal cells it is upregulated, leading to G‐CSF production and the induction of myelostimulation. It thus appears that A3AR agonists act as tumor growth inhibitors, simultaneously maintaining the myeloid system, capable of preventing the damage of chemotherapeutic agents. Drug Dev. Res. 58:386–389, 2003. © 2003 Wiley‐Liss, Inc.
Effects of adenosine on prostate adenocarcinoma PC‐3 and bladder carcinoma J82 cell lines
Authors: Nucciarelli Fabio , Mearini Ettore , Minelli Alba
Published: May 2003

Prostate adenocarcinoma PC‐3 and bladder carcinoma J82 cell lines were used to investigate the role of adenosine in the modulation of cell growth. Our results show that adenosine inhibited cell proliferation in both cell lines and markedly induced apoptosis only in J82 cells. PC‐3 and J82 cells showed typical sigmoid growth curves. Only the J82 growth curve was modified by the addition of adenosine deaminase, indicating that this cell line is sensitive to the presence of endogenous extracellular adenosine. Exogenous extracellular adenosine induced a dose‐dependent decrease of cell growth in both cell lines. 2′‐Deoxyadenosine and dipyridamole were used to investigate whether the growth inhibitory effect of adenosine was related to cellular uptake or to receptor‐mediated action. Our results show that 2′‐deoxyadenosine was a less effective inhibitor for J82 than PC‐3 cells. Dipyridamole reduced the inhibitory effect of adenosine in both cell lines. The determination of viability associated with Hoechst staining showed that adenosine clearly induced apoptosis in J82 cell lines but was less effective in PC‐3 cell lines. In conclusion, we have shown that the growth of prostate adenocarcinoma PC‐3 and bladder carcinoma J82 cell lines is inhibited by adenosine and that adenosine is capable of inducing apoptosis, although to a different extent in both cell lines. Drug Dev. Res. 58:390–395, 2003. © 2003 Wiley‐Liss, Inc.
Adenosine downregulates cytokine‐induced expression of intercellular adhesion molecule‐1 on rheumatoid synovial fibroblasts independently of adenosine receptor signaling
Authors: Nakazawa Takashi , Koshiba Masahiro , Kosaka Hidekazu , Tsuji Goh , Nakamachi Yuji , Saura Ryuichi , Kurosaka Masahiro , Tanaka Yoshiya , Kumagai Shunichi
Published: May 2003

Adhesion of fibroblast‐like synoviocytes (FLSs) to T cells through the interaction of lymphocyte function‐associated antigen‐1 (LFA‐1) and intercellular adhesion molecule‐1 (ICAM‐1) plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA). We therefore used flow cytometry and quantitative polymerase chain reaction (PCR) to examine the effect of adenosine and its derivatives on expression of ICAM‐1 induced by tumor necrosis factor‐alpha and interferon‐gamma in primary rheumatoid FLSs (RA‐FLSs) and E11 cells, an RA‐FLS line. Exposing cells to adenosine (5–500 µM) for 24 h in the presence of coformycin, an adenosine deaminase inhibitor, concentration‐dependently inhibited cytokine‐induced transcription of ICAM‐1 mRNA, as well as subsequent surface expression of the protein. Although transcription of all four adenosine receptor isoforms has been detected in FLSs, neither the A1 receptor agonist R‐PIA, the A2A receptor agonist CGS21680 nor the A3 agonist Cl‐IB‐MECA had any effect on cytokine‐induced ICAM‐1 expression. Conversely, A1/A2 receptor antagonist xanthine amine congener and A2A antagonist ZM240385 both failed to suppress the effect of adenosine. Adenosine appears to inhibit cytokine‐induced ICAM‐1 expression in FLSs independently of adenosine receptor‐mediated signaling. By contrast, the effect of adenosine was neutralized by nitrobenzylmercaptopurin, a nucleoside transporter inhibitor, or by ABT702, an adenosine kinase inhibitor. This suggests that adenosine taken up via the nucleoside transporter is phosphorylated by adenosine kinase, and the resultant phospho‐adenosine interferes with the ICAM‐1 transcription and cell surface expression. Downregulation of T cell–FLS interaction by adenosine may thus represent a novel approach to the treatment of RA. Drug Dev. Res. 58:368–376, 2003. © 2003 Wiley‐Liss, Inc.
A3receptors in cortical neurons: Pharmacological aspects and neuroprotection during hypoxia
Authors: Lewerenz A. , Hentschel S. , Vissiennon Z. , Michael S. , Nieber K.
Published: May 2003

Adenosine, which is released under pathophysiological conditions such as hypoxia or ischemia, is involved in a variety of regulatory processes related to neuroprotection. Major advances in the research on neuronal adenosine receptors have provided a better understanding of the mechanisms underlying the neuroprotective effects during hypoxia. The therapeutic potential of adenosine was recognized several years ago, but only the development of stable and selective adenosine receptor agonists and antagonists has offered novel approaches for the pharmacological manipulation of the receptor activity. To date, four G protein coupled receptors have been cloned and identified in the central nervous system: A1, A2A, A2B, and A3.The neuroprotective effects of adenosine are mediated primarily by the activation of A1receptors. Knowledge of the physiological role of A3receptors in the brain is still limited. This article focuses on new evidences referring to possible functions of A3receptors in the CNS, especially the role during hypoxia. Electrophysiological investigations on brain slices give us new insights concerning mechanisms of synaptic modulation. The data from pyramidal cells of the rat cingulate cortex show that a high level of endogenous adenosine (occuring during hypoxia) activates A3receptors, which mediates a depression of the synaptic transmission. The A3receptors inhibit the glutamate release additionally to and independently from the A1receptors. The two distinct mechanisms of synaptic modulation contribute to the neuroprotective action of adenosine during hypoxia and offer new approaches for therapeutic strategies. Drug Dev. Res. 58:420–427, 2003. © 2003 Wiley‐Liss, Inc. © 2003 Wiley‐Liss, Inc.
Mechanisms of cardiac protection with Overexpression of A1 adenosine receptors
Authors: Lankford Amy R. , Cerniway Rachael J. , Regan Sara E. , Crawford Marguerite M. , Byford Anne M. , Matherne G. Paul
Published: May 2003

Myocardial damage from ischemia/reperfusion injury can be minimized through endogenous protective mechanisms, including activation of A1 adenosine receptors. Transgenic mice with cardiac‐specific A1 adenosine receptor overexpression (A1AR Trans) have demonstrated functional and metabolic tolerance to in vitro and in vivo myocardial ischemia/reperfusion injury. The purpose of this investigation is to examine the role of p38 MAP kinase in A1 receptor‐mediated cardioprotection. Activation of p38 MAPK by A1 adenosine receptor stimulation was evaluated in neonatal rat cardiomyocytes subjected to simulated ischemia. A1 activation by cyclopentyladenosine decreased cell death and simultaneously enhanced p38 phosphorylation by simulated ischemia. The role of p38 MAP kinase activation in cardioprotection with A1 adenosine receptor overexpression was evaluated in isolated perfused hearts from A1AR Trans mice subjected to 20 min ischemia and 30 min reperfusion. Inhibition of p38 MAPK activity with 10 μM SB‐203580 prior to ischemia and during reperfusion decreased postischemic total functional recovery in A1AR Trans hearts from 54 ± 1 to 27±7% of maximal and increased final EDP from 10±3 mmHg to 34±8 mmHg. A1 adenosine receptor‐mediated activation of p38 MAP kinase in cardiomyocytes is involved in the protection of cells from ischemic death. Tolerance to ischemic injury by A1 receptor overexpression is dependent upon activation of p38 MAPK. These findings suggest that adenosine A1 mediated cardioprotection in transgenic mice involves activation of the p38 MAP kinase cascade. Drug Dev. Res. 58:439–446, 2003. © 2003 Wiley‐Liss, Inc.