bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Structures and Catalytic Properties of Bis(2‐pyridylimino)‐ isoindolatopalladium Complexes
Authors: Siggelkow Bettina , Meder Markus B. , Galka Christian H. , Gade Lutz H. 
Published: June 2004

AbstractReaction of the bis(2‐pyridylimino)isoindole derivatives (10‐Me)‐BPI (1a), (11‐Me)‐BPI (1b), (11‐Br)‐BPI (1c), (4‐Me)‐BPI (1d) and 4‐Me‐10‐tBuBPI (1e) with [PdCl2(PhCN)2] and triethylamine in benzene gave the square‐planar palladium(II) complexes [PdCl{(10‐Me)‐BPI}] (2a), [PdCl{(11‐Me)‐BPI}] (2b), [PdCl{(11‐Br)‐BPI}] (2c), [PdCl(4‐MeBPI)] (2d) and [PdCl(4‐Me‐10‐tBuBPI)] (2e), respectively. Extraction of the crude product 2b with aqueous sodium carbonate solution led to the formation of the dinuclear carbonato‐bridged complex [{(11‐Me‐BPI)Pd}2(μ‐CO3)] (3) which was characterized by an X‐ray structure analysis. Reaction of 11‐Br‐BPI (1c) with a large excess (6 equiv.) of the acetylenes Me3SiCCH, Ph3SiCCH and PhCCH under Sonogashira conditions gave the alkynylated derivatives 11‐(Me3SiCC)‐BPI (4a), 11‐(Ph3SiCC)‐BPI (4b) and 11‐(PhCC)‐BPI (4c), which were metallated with bis(benzonitrile)dichloropalladium(II) to yield the PdII complexes [PdCl{11‐(Me3SiCC)‐BPI}] (5a), [PdCl{11‐(Ph3SiCC)‐BPI}] (5b) and [PdCl{11‐(PhCC)‐BPI}] (5c), respectively. The activity of 2b in the catalytic hydrogenation of C=C double bonds was tested for the reaction with styrene, 1‐octene and cyclohexene. The stability of the palladium complex, the reproducibility of the reaction kinetics, the different behaviour towards the three olefins chosen as substrates, as well as the possibility of isolating the non‐decomposed catalyst after several catalytic runs, provides circumstantial evidence for molecular catalysis with the BPI‐palladium complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Cover Picture: Cobalt‐Mediated Cyclooligomerization Reactions of Borylacetylenes (Eur. J. Inorg. Chem. 13/2004)
Authors: Goswami Avijit , Maier Claus‐Jürgen , Pritzkow Hans , Siebert Walter 
Published: June 2004

AbstractThe cover picture shows the molecular structure of a (1,3‐diboryl‐2,4‐diphenylcyclobutadiene)(cyclopentadienyl)cobalt complex obtained in an attempt to trimerize 1‐(dithiocatecholboryl)‐2‐phenylacetylene with CpCo(CO)2. Details are discussed in the article by W. Siebert et al. on p. 2635 ff.
A 4‐year epidemiological study of typical and atypical eating disorders: preliminary evidence for subgroups of atypical eating disorders with different natural outcomes
Authors: Cotrufo P. , Monteleone P. , Castaldo E. , Maj M. 
Published: June 2004

AbstractBackgroundsWe designed a two‐step prospective study aiming to detect cases with full and atypical eating disorders (EDs) in a population of female high‐school students (first step) and to assess their natural outcome after a 4‐year time period (second step).MethodsIn the first step, we screened female students in their first year of high school by means of the EDI‐2 and GHQ‐28 questionnaires. Those students identified as being at risk for an ED underwent a psychiatric interview. In the second step, 4 years later, we tested schoolgirls in their last year of high school by adopting the same procedure as the first step.Results140 subjects participated in both steps. In the first step, we identified one subject with full‐blown bulimia nervosa (BN), one with partial‐syndrome BN, two with subclinical BN and eight with subclinical anorexia nervosa (AN). At the reassessment 4 years later, none of the girls had received any form of help. The full‐blown BN case, the partial‐syndrome BN case and one of the subclinical AN cases persisted unchanged; one of the subclinical BN cases shifted to subclinical AN; the remaining subclinical cases remitted spontaneously. Moreover, we identified 12 new cases of EDs.ConclusionsPresent findings provide the first evidence that subclinical AN and subclinical BN represent unstable states that can spontaneously remit over time. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Anorectic symptomatology as a prodrome of schizophrenia: four case reports
Authors: Kelly Lisa , Kamali Moayyad , Brennan Thomas 
Published: June 2004

AbstractWe describe four patients who originally presented with a diagnosis of adolescent anorexia nervosa and were subsequently diagnosed with schizophrenia. Overt positive symptoms of schizophrenia emerged during the course of treatment for the eating disorder. Symptoms such as social withdrawal and reduced work or academic performance, which had previously been attributed to the eating disorder, we considered to be negative symptoms of schizophrenia. We hypothesize that anorectic symptomatology may have represented prodromal features of schizophrenia in these patients. The clinical implications are discussed. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Enhanced inhibitive effects of combination of rofecoxib and octreotide on the growth of human gastric cancer
Authors: Tang Chengwei , Liu Chunlun , Zhou Xuchun , Wang Chunhui 
Published: June 2004

AbstractOur previous studies indicated that cyclooxygenase‐2 inhibitor or octreotide could suppress the proliferation of gastric adenocarcinoma in vitro or in vivo. The present study was aimed to find whether rofecoxib combined with octreotide could enhance the inhibitive effects on the growth of gastric cancer. The effect of rofecoxib or octreotide on proliferation of gastric cancer cell line was determined by 3H‐thymidine ribotide incorporation. The TdT‐mediated dUTP nick end‐labeling assay was used to detect the apopotosis. To determine their synergic antineoplastic effects, the interaction between rofecoxib and octreotide on SGC‐7901 cell was evaluated by the median effect plot. After orthotopical implantion of xenografts of human gastric cancer in stomach, nude mice were given rofecoxib plus octreotide for 8 weeks. Cyclooxygenase‐2 in gastric cancer tissues was measured by immunohistochemistry. Combination of rofecoxib and octreotide presented synergistic effect (combination index < 1) in the majority of responses. The inhibitory rate for xenografts in nude mice was 89.7% in rofecoxib group. Combination of rofecoxib and octreotide enhanced inhibitory rate to 98.8%. The combination greatly increased the apoptotic index (78.20% ± 6.45%) of the xenografts as compared with that of using rofecoxib alone (46.60% ± 3.42%); the difference was very significant (p < 0.001). Rofecoxib could inhibit the activity of cyclooxygenase‐2 in the tissue of gastric adenocarcinomas of nude mice. Our results indicate that combination of rofecoxib and octreotide significantly enhances the antiproliferative effect in gastric adenocarcinoma, which might have potential therapeutic value. © 2004 Wiley‐Liss, Inc.
Multiple mechanisms of action of ZR2002 in human breast cancer cells: A novel combi‐molecule designed to block signaling mediated by the ERB family of oncogenes and to damage genomic DNA
Authors: Brahimi Fouad , Rachid Zakaria , Qiu Qiyu , McNamee James P. , Li Yu‐Jiang , Tari Ana M. , Jean‐Claude Bertrand J. 
Published: June 2004

AbstractThe mechanism of action of ZR2002, a chimeric amino quinazoline designed to possess mixed EGFR tyrosine kinase (TK) inhibitory and DNA targeting properties, was compared to those of ZR01, a reversible inhibitor of the same class and PD168393, a known irreversible inhibitor of EGFR. ZR2002 exhibited 4‐fold stronger EGFR TK inhibitory activity than its structural homologue ZR01 but was approximately 3‐fold less active than the 6‐acrylamidoquinazoline PD168393. It preferentially blocked EGF and TGFα‐induced cell growth over PDGF and serum. It also inhibited signal transduction in heregulin‐stimulated breast tumour cells, indicating that it does not only block EGFR but also its closely related erbB2 gene product. In contrast to its structural homologues, ZR2002 was capable of inducing significant levels of DNA strand breaks in MDA‐MB‐468 cells after a short 2 hr drug exposure at a concentration as low as 10 μM. Reversibility studies using whole cell autophosphorylation and growth assays in human breast cell lines showed that in contrast to its reversible inhibitor counterpart ZR01, ZR2002 induced irreversible inhibition of EGF‐stimulated autophosphorylation in MDA‐MB‐468 cells and irreversible inhibition of cell growth. Moreover despite possessing a weaker binding affinity than PD168393, it induced a significantly more sustained antiproliferative effect than the latter after a pulse 2 hr exposure. More importantly, in contrast to ZR01 and PD168393, ZR2002 was capable of inducing significant levels of cell death by apoptosis in MDA‐MB‐468 cells. The results in toto suggest that the superior antiproliferative potency of ZR2002 may be due to its ability to induce a protracted blockade of receptor tyrosine kinase‐mediated signaling while damaging cellular DNA, a combination of events that may trigger cell‐killing by apoptosis. © 2004 Wiley‐Liss, Inc.
Synthesis of low‐shrinkage polymerizable liquid‐crystal monomers
Authors: Satsangi Neera , Rawls H. Ralph , Norling Barry K. 
Published: June 2004

AbstractPolymerization shrinkage remains a major barrier to the universal use of resin restorative in large posterior cavity preparations. A new bifunctional liquid crystal (LC) monomer, 2‐(t‐butyl), 1,4‐bis‐[4‐(6‐acryloxy‐hexane‐1‐oxy)‐benzoyloxy] benzene, with exceptionally low polymerization shrinkage, has recently been discovered. The purpose of this communication is to report a new, easy, high‐yield synthetic route to synthesize this compound in comfortable larger batches. Synthetic and isolation details, chemical characteristics, and the polymerizable properties of a new structurally related by‐product monomer, namely, 2‐(t‐butyl),1‐[4‐(6‐acryloxy‐hexane‐1‐oxy)‐benzoyloxy], 4‐[4‐{6‐(3‐acryl oxy‐propionoxy)‐hexane‐1‐oxy}‐benzoyloxy]‐benzene, is also reported. The structural confirmation of this by‐product indicates that it resulted from the Michael‐type addition of acrylate ion on one of the terminal acryloxy groups of 2‐(t‐butyl), 1,4‐bis‐[4‐(6‐acryloxy‐hexane‐1‐oxy)‐benzoyloxy] benzene. The by‐product itself, as well as the natural blend of the aforesaid both products as formed in the reaction mixture, also polymerized at room temperature with lesser volume shrinkage as compared to the conventional control (GTE) at similar degrees of conversion. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 153–158, 2004
Denitrification in aqueous FeEDTA solutions
Authors: van der Maas Peter , Harmsen Loes , Weelink Sander , Klapwijk Bram , Lens Piet 
Published: June 2004

AbstractThe biological reduction of nitric oxide (NO) in aqueous solutions of FeEDTA is an important key reaction within the BioDeNOx process, a combined physico‐chemical and biological technique for the removal of NOx from industrial flue gasses. To explore the reduction of nitrogen oxide analogues, this study investigated the full denitrification pathway in aqueous FeEDTA solutions, ie the reduction of NO3−, NO2−, NO via N2O to N2 in this unusual medium. This was done in batch experiments at 30 °C with 25 mmol dm−3 FeEDTA solutions (pH 7.2 ± 0.2). Also Ca2+ (2 and 10 mmol dm−3) and Mg2+ (2 mmol dm−3) were added in excess to prevent free, uncomplexed EDTA. Nitrate reduction in aqueous solutions of Fe(III)EDTA is accompanied by the biological reduction of Fe(III) to Fe(II), for which ethanol, methanol and also acetate are suitable electron donors. Fe(II)EDTA can serve as electron donor for the biological reduction of nitrate to nitrite, with the concomitant oxidation of Fe(II)EDTA to Fe(III)EDTA. Moreover, Fe(II)EDTA can also serve as electron donor for the chemical reduction of nitrite to NO, with the concomitant formation of the nitrosyl‐complex Fe(II)EDTA–NO. The reduction of NO in Fe(II)EDTA was found to be catalysed biologically and occurred about three times faster at 55 °C than NO reduction at 30 °C. This study showed that the nitrogen and iron cycles are strongly coupled and that FeEDTA has an electron‐mediating role during the subsequent reduction of nitrate, nitrite, nitric oxide and nitrous oxide to dinitrogen gas. Copyright © 2004 Society of Chemical Industry
Reliable production of highly concentrated bioethanol by a conjunction of pervaporation using a silicone rubber sheet‐covered silicalite membrane with adsorption process
Authors: Ikegami Toru , Kitamoto Dai , Negishi Hideyuki , Iwakabe Koichi , Imura Tomohiro , Sano Tsuneji , Haraya Kenji , Yanagishita Hiroshi 
Published: June 2004

AbstractFor the production of highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, pervaporation performance was investigated using a silicalite membrane entirely covered with a silicone rubber sheet to prevent direct contact with acidic compounds. By using a resistance model for membrane permeation, the separation factor of the covered silicalite membrane towards ethanol can be estimated from the individual pervaporation performances of the silicalite membrane and the silicone rubber sheet. No decrease in the ethanol concentration through the silicone rubber sheet‐covered membrane was caused when ethanol solutions containing succinic acid were supplied. By directly passing the permeate‐enriched ethanol vapor mixed with water vapor through a dehydration column packed with a molecular sieve of pore size 0.3 nm, highly concentrated bioethanol up to 97% (w/w), greater than the azeotropic point in the ethanol/water binary systems, can be obtained from 9% (w/w) fermentation broth. Copyright © 2004 Society of Chemical Industry
The probabilistic key‐group method
Authors: Yarahmadi Bafghi A. R. , Verdel T. 
Published: June 2004

AbstractKey‐block approaches are widely used in the analysis of rock slopes. The key‐group method improves such analyses by taking into account groups of blocks instead of single blocks. Nevertheless, these stability analyses are usually carried out within a context where uncertainty may be a difficult problem to overcome. In the present paper, we propose introducing probabilistic approaches into the key‐group method in order to account for uncertainty in the mechanical parameters of the problem to be solved. Both the first‐order, second‐moment method (FOSM) and the advanced second‐moment method (ASMM) are considered herein and compared with Monte‐Carlo simulations through the use of five theoretical case studies. Lastly, the probabilistic key‐group method (PKGM) is qualified. Copyright © 2004 John Wiley & Sons, Ltd.
Modified modal methods for calculating eigenpair sensitivity of asymmetric damped system
Authors: Moon Yeong‐Jong , Kim Byoung‐Wan , Ko Man‐Gi , Lee In‐Won 
Published: June 2004

AbstractMany real systems such as moving vehicles on roads, missiles following trajectories and ships in sea water have asymmetric mass, damping and stiffness matrices. Eigen‐sensitivity analysis methods for the symmetric damped system cannot be used in the asymmetric damped case. Therefore, a method for calculating eigenpair sensitivity of the asymmetric damped system is needed. To do this, a modal method employing a modal superposition idea was recently developed. Since the accuracy of the modal method is dependent on the number of modes used in calculation, the modal method needs higher eigenvectors to guarantee the accuracy. In large‐scale systems, however, only a few lower modes are generally considered for the dynamic analysis. Hence, if the modal method is used to obtain the eigen‐sensitivity of the large‐scale system, the significant errors could not be avoided due to the lack of the information of higher modes. In this paper, the modified modal methods for computing the sensitivities of the eigenpairs of asymmetric damped system using a few lowest sets of modes are proposed. Numerical example shows that the proposed methods achieve better calculating efficiency than the previous modal method. Copyright © 2004 John Wiley Sons, Ltd.
Polymerization of pyrrole by isopolymetallates of vanadium/molybdenum and preparation of a polypyrrole–molybdenum blues nanocomposite
Authors: Ballav Nirmalya , Biswas Mukul 
Published: June 2004

AbstractOxidative polymerization of pyrrole (PY) was achieved in high yield (>90 %) by adding the monomer directly to isopolyvanadate (IPV) and isopolymolybdate (IPMo) solutions at selected pH. In the case of the IPV solution instantaneous precipitation of a black mass was obtained while in the IPMo solution in situ precipitation of polypyrrole (PPY) onto molybdenum blues (MB) formed through reduction of IPMo by PY resulting in a PPY‐encapsulated MB nanocomposite (PPY–MB). Formation of PPY was confirmed from Fourier‐transform infrared (FTIR) and thermogravimetric (TG) analyses. Transmission electron microscope (TEM) photographs for the composite revealed the formation of spherical particles of average size ≈75 nm. Scanning electron microscope (SEM) analyses showed the distinctive morphological patterns for PPY and PPY–MB composite. The direct current conductivity values for PPY prepared by IPV, IPMo and PPY–MB were of the order of 10−2, 10−4 and 10−6 S cm−1, respectively. Copyright © 2004 Society of Chemical Industry
Synthesis and characterization of acetylated syndiotactic polystyrene
Authors: Gao Yong , Li Hua‐Ming 
Published: June 2004

AbstractAcetylation of highly stereoregular syndiotactic polystyrene has been accomplished in a heterogeneous process by using carbon disulfide as the dispersing medium, and acetyl chloride and anhydrous aluminium chloride as acetylating agent and catalyst, respectively. The acetylation reaction can be well controlled and carried out to a high degree of acetylation. The resultant polymer was characterized by FTIR and NMR spectroscopy. The incorporation of acetyl groups into syndiotactic polystyrene was found to have an effect on the thermal properties of these new materials. The degree of crystallinity was decreased by the presence of acetyl groups, while the glass transition temperature increased. Copyright © 2004 Society of Chemical Industry
Homogeneous graft copolymerization of chitosan with methyl methacrylate by γ‐irradiation via a phthaloylchitosan intermediate
Authors: Liu Li , Li Yu , Zhang Wei‐an , Zhang Guoqing , Fang Yue‐e 
Published: June 2004

AbstractThe graft copolymerization of methyl methacrylate (MMA) onto chitosan was tried via a new protection‐graft‐deprotection procedure. Because the intermediate phthaloylchitosan was soluble in organic solvents, the graft copolymerization was carried out in a homogeneous system. Grafting was initiated by γ‐irradiation. The graft percentage extent was dependent on the irradiation dose and the concentration of MMA monomer, and copolymers with grafting above 100 % were readily prepared. The graft copolymers exhibited a high affinity not only for aqueous acid but also for some organic solvents. Differential scanning calorimetry measurements revealed the presence of a glass transition phenomenon, which could be ascribed to the poly(methyl methacrylate) side‐chains. Copyright © 2004 Society of Chemical Industry
Nanocomposites of polymer gel electrolyte based on poly(ethylene glycol diacrylate) and Mg–Al layered double hydroxides
Authors: Cho Mi Suk , Shin Bora , Nam Jae Do , Lee Youngkwan , Song Kigook 
Published: June 2004

AbstractThe present paper describes the synthesis and characterization of nanocomposite materials composed of the polymer gel electrolyte and a layered double hydroxide (LDH) inorganic filler. Mg–Al LDHs were prepared with various ratios of Mg/Al. It was observed that the layered structure of Mg–Al LDH was totally exfoliated by the PEGDA. The ionic conductivity and mechanical strength were highly improved in the nanocomposite systems. In the case of the composite films having 4.5 wt% of the Mg–Al LDH, the ionic conductivity reached 1.6 × 10−3 S cm−1 at room temperature. The incorporation of nanoparticles into the gel resulted in a two‐ or threefold increase in the tensile modulus. Copyright © 2004 Society of Chemical Industry
Epoxy/clay nanocomposites: further exfoliation of newly modified clay induced by shearing force of ball milling
Authors: Lu Hai‐jun , Liang Guo‐Zheng , Ma Xiao‐yan , Zhang Bao‐yan , Chen Xiang‐bao 
Published: June 2004

AbstractTo induce montmorillonite (MMT) to be further exfoliated and homogeneously dispersed in epoxy matrix (diglycidyl ether of bisphenol A) curing in the presence of diaminodiphenyl sulfone and obtain improved mechanical properties, a promising new method has been developed to prepare highly reinforced epoxy/MMT nanocomposites through exerting shearing force on epoxy/MMT solution by ball milling. Modifying agents, being combined with dodecylbenzyldimethylammonium chloride and meta‐xylylenediamine, were used to organically modify the clay (MMTII). Different resultant products were characterized by Fourier‐transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, etc, and the fracture surface of the mechanically tested specimens was also observed by scanning electronic microscopy. Results show that the novel MMTII possess a reactive interaction surface with the epoxy matrix. Exfoliation of the retained sandwich structure (being intercalated) or large agglomerates (undispersed MMTII) can be promoted by external shearing force of ball milling, and homogeneously dispersed MMTII nano‐sheets in epoxy matrix nanocomposites are typically observed. Mechanical properties, especially impact toughness, can be increasingly enhanced by the newly structured MMTII and ball milling. Impact strength is increased up to 48.1 kJ m−2 from 32.1 kJ m−2 at 3 wt% MMTII content, which is about 50 % higher than that of pristine matrix, and the flexural strength can also be enhanced by about 8 % higher. Copyright © 2004 Society of Chemical Industry
Influence of lanthanide triflate compounds on formation of networks from DGEBA and γ‐butyrolactone
Authors: Mas Cristina , Mantecón Ana , Serra Angels , Ramis Xavier , Salla Josep Maria 
Published: June 2004

AbstractDiglycidylether of bisphenol A (DGEBA) was cured with γ‐butyrolactone (γ‐BL) using different lanthanide triflates as catalysts. Fourier transform infrared spectroscopy was used to study the different evolutions of the four elemental processes that took place during curing with lanthanum and ytterbium triflates. The greatest differences among the lanthanides were in oxophilicity and Lewis acidity. Differences in the coordination ability of the metal to the monomers were shown and according to the Pearson theory, were related to their different characteristics. Differences in the reactivity of the systems were related to the differences in the Lewis acidity of the initiators. The evolution of the contraction during curing using different lanthanide triflates was monitored by thermomechanical analysis. All systems showed that contraction took place in two stages and that there was an intermediate region, associated with gelation, with no contraction. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3782–3791, 2004