bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extracellular metabolites in the cortex and hippocampus of epileptic patients
Authors: Cavus Idil , Kasoff Willard S. , Cassaday Michael P. , Jacob Ralph , Gueorguieva Ralitza , Sherwin Robert S. , Krystal John H. , Spencer Dennis D. , Abi‐Saab Walid M. 
Published: January 2005

AbstractInterictal brain energy metabolism and glutamate–glutamine cycling are impaired in epilepsy and may contribute to seizure generation. We used the zero‐flow microdialysis method to measure the extracellular levels of glutamate, glutamine, and the major energy substrates glucose and lactate in the epileptogenic and the nonepileptogenic cortex and hippocampus of 38 awake epileptic patients during the interictal period. Depth electrodes attached to microdialysis probes were used to identify the epileptogenic and the nonepileptogenic sites. The epileptogenic hippocampus had surprisingly high basal glutamate levels, low glutamine/glutamate ratio, high lactate levels, and indication for poor glucose utilization. The epileptogenic cortex had only marginally increased glutamate levels. We propose that interictal energetic deficiency in the epileptogenic hippocampus could contribute to impaired glutamate reuptake and glutamate–glutamine cycling, resulting in persistently increased extracellular glutamate, glial and neuronal toxicity, increased lactate production together with poor lactate and glucose utilization, and ultimately worsening energy metabolism. Our data suggest that a different neurometabolic process underlies the neocortical epilepsies. Ann Neurol 2005;57:226–235
Three‐centre RhHSn bonds: an NMR study of the effects of varying the electron density on rhodium
Authors: Carlton Laurence 
Published: January 2005

AbstractThe complexes [Rh(X)(H)(SnPh3)(PPh3)(L)] (X = NCBPh3 (a), N(CN)2 (b), NCS (c), NCO (d), N3 (e); L = 1‐methylimidazole) (1) show systematic changes in δ(119Sn), δ(103Rh), J(119Sn–1H) and J(119Sn–103Rh) that are related to the electron‐donating properties of X. As X becomes more electron‐rich, δ(103Rh), J(119Sn–1H) and J(119Sn–103Rh) increase and δ119Sn) decreases. The related complexes trans‐[Rh(X)(H)(SnPh3)(PPh3)2(L)] (X = N(CN)2, NCO; L = 4‐carboxymethylpyridine (x), pyridine (y) and 4‐dimethylaminopyridine (z)) (2), show a continuation of the trends in δ(119Sn) and J(119Sn–1H), but not δ(103Rh) or J(119Sn–103Rh). Data for 1 and 2 show that within certain limits of type of ligand varied (X = N‐donor, L = a pyridine) and coordination geometry, the response of δ(119Sn) and J(119Sn–1H) to changes in electron density on rhodium is largely independent of the means by which the change is effected.Copyright © 2001 John Wiley & Sons, Ltd.
Catalytic activity of some organolanthanoid derivatives in styrene and propene polymerization
Authors: Kirillov Evgueni N. , Fedorova Elena A. , Trifonov Alexander A. , Bochkarev Mikhail N. 
Published: January 2005

AbstractOrganolanthanoids of several classes were examined as potential styrene and propene polymerization catalysts. They are: molecular hydrides of divalent lanthanoids (samarium, europium, ytterbium); naphthalene and stilbene complexes of neodymium(III), samarium(II), europium(II), ytterbium(II), lutetium(III); amides and alkoxides (including heterobifunctional derivatives) of praseodymium(III), neodymium(III), samarium(II), europium(II), thulium(III), ytterbium(II, III); thiolate of samarium(III); phenyl and phenylethinyl derivatives of europium(II), thulium(III), ytterbium(II); methylytterbium cluster Yb8 (μ‐CH3)14(μ‐CH2)(THF)6; heterobimetallic samarium(II), ytterbium(II, III) complexes; diazabutadiene ytterbium(III) derivatives; metallic praseodymium and ytterbium, activated by iodine. The highest activity in styrene polymerization revealed hydrides, naphthalene and stilbene complexes of samarium(II), europium(II) and ytterbium(II). In the propene polymerization only [(η5‐C5H4)CH2CH­(CH2OBu)(η1‐O)]YbMe(THF) displayed noticeable activity.Copyright © 2001 John Wiley & Sons, Ltd.
Organometallic complexes with biological molecules. XV. Effects of tributyltin(IV)chloride on enzyme activity, Ca2+, and biomolecule and synthesis in Ciona intestinalis (Urochordata) ovary
Authors: Puccia E. , Mansueto C. , Cangialosi M. V. , Fiore T. , Di Stefano R. , Pellerito C. , Triolo F. , Pellerito L. 
Published: January 2005

AbstractConsiderable attention has been given in recent years to the possibility that xenobiotics in the environment may affect reproduction in animals. In this study, the relative impact of tributyltin(IV) (TBT) chloride, one of the most toxic environmental pollutants, was investigated using Ciona intestinalis ovary as a model system. The pleiotropic effects of TBT exposure are concentration dependent and include a decrease of ATP levels, lipid content and nucleic acid content and synthesis. In contrast, a marked increase in calcium (Ca2+) and glucose content is observed. Furthermore, TBT alters enzymatic activity, inhibiting creatine kinase and stimulating alkaline phosphatase and cholinesterase (at concentrations higher than 10−5M in sterile sea water solution). The implications of these effects on reproduction and embryonal development are discussed, along with the possibility that they reflect an extreme cellular defence mechanism triggered to avoid deleterious consequences for the survival of the species.Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis, antitumor activity and crystal structure of the triphenyltin derivative of exo‐7‐oxa‐bicyclo[2,2,1]hept‐5‐ene‐3‐N‐p‐tolylamide‐2‐acid
Authors: Li Jinshan , Ma Yongqiang , Liu Runchang , Li Jing 
Published: January 2005

AbstractThe synthesis and crystal structure of­Ph3SnO2CCHCHCH:CHCH(O)CHCONHC6H4­CH3·CH2Cl2 are reported. The monomer units­are bridged by the carbonyl oxygen of the amide group, thus forming a polymer in which each tin atom is best described as having a distorted five‐coordinate geometry. There is a relatively strong intramolecular hydrogen bond between the amide hydrogen and the ether oxygen. The in vitro antitumor activities of the title compound against HL‐60, BGC‐823, Bel‐7402, SKOV3, KB and Hela tumor lines are reported. The title compound shows a distinct advantage when the metal (tin) is introduced into the acid.Copyright © 2001 John Wiley & Sons, Ltd.
Rhodium‐ and ruthenium‐complex‐catalyzed condensation of ferrocene‐containing dithiols and diols with diarylsilanes to give silaferrocenophanes and ferrocene polymers
Authors: Yamaguchi Isao , Ishii Hidetake , Sakano Tatsuaki , Osakada Kohtaro , Yamamoto Takakazu 
Published: January 2005

Abstract1,1′‐Ferrocenedithiol reacts with di(4‐methoxyphenyl)silane, diphenylsilane, and di(4‐fluorophenyl)silane in the presence of RhCl(PPh3)3 catalyst to give mixtures of 2,2‐diaryl‐1,3‐dithia‐2‐sila[3]ferrocenophanes (1a–3a) and (FcSSiAr2S)
n (Fc = 1,1′‐ferrocenylene; 1b: Ar = C6H4OMe‐4; 2b: Ar = Ph; 3b: Ar = C6H4F‐4). The products are isolated and characterized by NMR spectroscopy and elemental analyses. The polymers 1b–3b, obtained from a toluene‐soluble fraction of the products, show GPC elution patterns corresponding to Mn values of 2700–4600 (polystyrene standards). The UV–vis spectra of the ferrocenophanes and polymers exhibit a d–d transition peak at about 440 nm, while the polymers show a π–π* transition peak at 320–330 nm. The cyclic voltammograms of 3a (Ar = C6H4F − 4) and 3b show a reversible redox of the iron center at 0.27 V and 0.35 V (Ag+/Ag) respectively. Reaction of 1,1′‐ferrocenedimethanol with diphenylsilane in the presence of RuCl2(PPh3)3 catalyst results in selective formation of 3,3‐diphenyl‐2,4‐dioxa‐3‐sila[5]ferrocenophane (4), whose structure was determined by X‐ray crystallography. Copyright © 2001 John Wiley & Sons, Ltd.
Various ligand‐stabilized metal nanoclusters as homogeneous and heterogeneous catalysts in the liquid phase
Authors: Toshima Naoki , Shiraishi Yukihide , Teranishi Toshiharu , Miyake Mikio , Tominaga Toshihiro , Watanabe Hiroshi , Brijoux Werner , Bönnemann Helmut , Schmid Günter 
Published: January 2005

AbstractLigand‐stabilized noble metal nanoclusters, prepared by various chemical methods by different research groups in Japan and Germany, were characterized and examined by a common method for application to the catalysis for hydrogenation of olefins in homogeneous and heterogeneous systems in the liquid phase. The mean diameters of palladium, platinum, rhodium and Pd/Pt nanoclusters stabilized by various ligands range from 1.3 to 3.2 nm if prepared by a single reaction, and from 2.2 to 4.0 nm if prepared by a stepwise growth method. The Stokes radii of metal nanoclusters stabilized by surfactants range from 1.7 to 2.1 nm, suggesting a thickness of the protective layer from 1.1 to 1.4 nm, whereas those stabilized by polymers give much larger values, suggesting the formation of aggregates. The catalytic activities of the metal nanoclusters, evaluated by hydrogenation of 1,3‐cyclooctadiene and methyl acrylate, depend mainly upon the particle size, i.e. the smaller the size, the higher the activity. However, a strongly interacting ligand like tetraoctylammonium halide and 1,10‐phenanthroline can disturb the hydrogenation. In contrast, the activities of heterogeneous catalysts supported on charcoal depend strongly on the covering strength of the stabilizer. Copyright © 2001 John Wiley & Sons, Ltd.
The effect of phenyltin chlorides on the phase polymorphism of dipalmitoylphosphatidylcholine
Authors: Różycka‐Roszak Bożenna , Pruchnik Hanna 
Published: January 2005

AbstractThe effects of diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT) on polymorphic phase behaviour of aqueous dispersions of a dipalmitoylphosphatidylcholine (DPPC) bilayer were investigated by means of
31P NMR. It is suggested that DPhT induces interdigitated gel phase formation and TPhT induces hexagonal phase formation. The toxic activities of DPhT and TPhT seem to be connected with their ability to induce changes in the membrane structure. Copyright © 2001 John Wiley & Sons, Ltd.
Di‐n‐butyltin(IV) derivatives of bis(carboxymethyl)benzylamines: synthesis, NMR and X‐ray structure characterization and in vitro antitumour properties
Authors: Mancilla Teresa , Carrillo Lourdes , Zamudio Rivera Luis S. , Camacho Camacho Carlos , Vos Dick de , Kiss Robert , Darro Francis , Mahieu Bernard , Tiekink Edward R. T. , Rahier Hubert , Gielen Marcel , Kemmer Martine , Biesemans Monique , Willem Rudolph 
Published: January 2005

AbstractFour di‐n‐butyltin(IV) derivatives of bis(carboxymethyl)benzylamines were synthesized and their structure characterized by 1H,13C and ­117/119Sn NMR, Mössbauer spectroscopy and mass spectrometry. The derivative substituted in the meta position by a methyl group has been further characterized by X‐ray crystallography. This compound exhibits a distorted trigonal bipyramidal geometry at tin. The NMR data in solution, as well as other spectroscopic results in the solid state, confirm this structure for all the compounds. Evidence is provided to show that the compounds are more highly associated in concentrated solution than in the solid state. Their in vitro antitumour activity is reported. Copyright © 2001 John Wiley & Sons, Ltd.
Development of a bio‐based composite material from soybean oil and keratin fibers
Authors: Hong Chang K. , Wool Richard P. 
Published: January 2005

AbstractA novel bio‐based composite material, suitable for electronic as well as automotive and aeronautical applications, was developed from soybean oils and keratin feather fibers (KF). This environmentally friendly, low‐cost composite can be a substitute for petroleum‐based composite materials. Keratin fibers are a hollow, light, and tough material and are compatible with several soybean (S) resins, such as acrylated epoxidized soybean oil (AESO). The new KFS lightweight composites have a density ρ ≈ 1 g/cm3, when the KF volume fraction is 30%. The hollow keratin fibers were not filled by resin infusion and the composite retained a significant volume of air in the hollow structure of the fibers. Due to the retained air, the dielectric constant, k, of the composite material was in the range of 1.7–2.7, depending on the fiber volume fraction, and these values are significantly lower than the conventional silicon dioxide or epoxy, or polymer dielectric insulators. The coefficient of thermal expansion (CTE) of the 30 wt % composite was 67.4 ppm/°C; this value is low enough for electronic application and similar to the value of silicon materials or polyimides used in printed circuit boards. The water absorption of the AESO polymer was 0.5 wt % at equilibrium and the diffusion coefficient in the KFS composites was dependent on the keratin fiber content. The incorporation of keratin fibers in the soy oil polymer enhanced the mechanical properties such as storage modulus, fracture toughness, and flexural properties, ca. 100% increase at 30 vol %. The fracture energy of a single keratin fiber in the composite was determined to be about 3 kJ/m2 with a fracture stress of about 100–200 MPa. Considerable improvements in the KFS composite properties should be possible by optimization of the resin structure and fiber selection. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1524–1538, 2005
New melamine‐formaldehyde‐ketone polymers: I. Synthesis of reactive solvents of melamine from selected ketones
Authors: Głowacz‐Czerwonka Dorota , Kucharski Mieczysław 
Published: January 2005

AbstractReactive solvents of melamine were prepared by reacting ketones with an excess of formaldehyde in the presence of triethylamine catalyst. The ketones used were cyclohexanone, cyclopentanone, acetophenone, benzoylacetone, biacetyl, or ethyl‐methyl ketone. The structures of the resulting reactive solvents were studied by 1H‐NMR. The best solubility of melamine was observed for the solvent derived from ethyl‐methyl ketone. Preliminary attempts at curing the melamine solutions yielded melamine‐formaldehyde‐ketone polymers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95:1319–1332, 2005
Effect of AgNO3–MnCl2 mixed fillers on the physical properties of polystyrene films
Authors: Tawansi A. , El‐Khodary A. , Oraby A. H. , Youssef A. E. 
Published: January 2005

AbstractThis study deals with the effects of various filling levels of a mixture of two transition compounds [(X)AgNO3(10 − X)MnCl2] on the structural, electrical, and magnetic properties of atactic polystyrene (PS) films. X‐ray diffraction (XRD) scans showed two main peaks for unfilled PS films. Crystalline peaks were unexpectedly detected with the filling and could be correlated to the formation of clusters. The IR transmission spectra revealed characteristic PS peaks. Certain IR peaks could be taken as evidence for the formation of polaron and bipolaron bound states in the polymeric matrix. The direct‐current (DC) electrical conduction measurements suggested that the conduction mechanism could be attributed to phonon‐assisted charge carrier hopping according to the interpolaron hopping model. The DC magnetic susceptibility results at 90–235 K obeyed the Curie–Weiss law. The negative values of the paramagnetic Curie temperature (θp) indicated the possibility of an antiferromagnetic exchange interaction, whereas the positive values of θp suggested a ferromagnetic exchange interaction at low temperatures. An electron spin resonance (ESR) spectrum at X = 0% revealed a broad Lorentzian signal. This suggested the presence of aggregated Mn2+ and was confirmation of cluster formation found in XRD studies. On the other hand, ESR spectra at higher values of X depicted hyperfine structures characterized by the six unresolved lines of the manganese nucleus, indicating the existence of isolated Mn2+. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95:1333–1341, 2005
Preparation of novel syndiotactic poly(vinyl alcohol) microspheres through the low‐temperature suspension copolymerization of vinyl pivalate and vinyl acetate and heterogeneous saponification
Authors: Lee Se Geun , Kim Jae Pil , Lyoo Won Seok , Kwak Jin Woo , Noh Seok Kyun , Park Chan Sik , Kim Jae Hyun 
Published: January 2005

AbstractSyndiotactic poly(vinyl alcohol) (PVA)/poly(vinyl pivalate/vinyl acetate) [P(VPi/VAc)] microspheres, with a skin–core structure, were prepared through the heterogeneous saponification of copolymers of vinyl pivalate (VPi) and vinyl acetate (VAc). For the preparation of P(VPi/VAc) microspheres with various particle sizes and a uniform particle size distribution (which are promising precursors of syndiotactic PVA embolic materials to be introduced through catheters for the management of gastrointestinal bleeders, arteriovenous malformations, hemangiomas, and traumatic rupture of blood vessels), VPi and VAc were suspension‐copolymerized at 30°C with a room‐temperature initiator, 2,2′‐azobis(2,4‐dimethylvaleronitrile). The effects of the polymerization conditions were investigated in terms of the size and size distribution of the suspension particles. P(VPi/VAc) microspheres, with various syndiotactic dyad (s‐dyad) contents, were produced through the control of the monomer feed ratio. In addition, monodisperse P(VPi/VAc) particles of various particle diameters were obtained by the separation and sieving of the polymerization product. Monodisperse P(VPi/VAc) microspheres of various particle sizes were partially saponified in the heterogeneous system, and the effects of the particle size and particle size distribution on the saponification rate were investigated in terms of the tacticity and the saponification time and temperature. Novel skin–core PVA/P(VPi/VAc) microspheres of various s‐dyad contents and degrees of saponification were successfully produced through the control of the various polymerization and saponification parameters. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1539–1548, 2005
Polysiloxane resins modified by bisglycidyl calix[4]arene: Preparation, characterization, and adsorption behavior toward metal ions
Authors: Li Cheng , Gong Shu‐Ling , Meng Ling‐Zhi , Hu Ling , Huang Huang , He Yong‐Bing 
Published: January 2005

AbstractTwo porous polysiloxane resins were prepared by the ring‐opening polycondensation of epoxy groups of bisglycidyl calix[4]arene with amino groups of polysiloxane microparticles that were prepared by the sol–gel method of cohydrolysis and condensation from γ‐aminopropyltriethoxysilane (RSC‐I) or 4‐aza‐6‐aminohexyltriethoxysilane (RSC‐II) with tetraethylorthosilicate. The resins were characterized by elemental analysis, DR–Fourier transform infrared spectra, Raman scattering spectra, scanning electron micrographs, and thermogravimetric analysis. The porous polysiloxane resins exhibited high thermostability and preconcentration potential for divalent Cu, Pb, and Hg ions, especially for the trivalent auric ion, relative to both the special cavity and the network structure of polysiloxane resins. The nitrogen atoms in resins also exert some auxiliary action. The enthalpy of the adsorption of two resins toward trivalent auric ion was evaluated to be 6.83 and 8.04 kJ/mol for RSC‐I and RSC‐II, respectively. © 2005 Wiley Periodicals,Inc. J Appl Polym Sci 95: 1310–1318, 2005
Relaxation phenomenon of poly(vinyl alcohol)/sodium carboxy methyl cellulose blend by thermally stimulated depolarization currents and thermal sample technique
Authors: Abd El‐Kader F. H. , Shehap A. M. , Abo‐Ellil M. S. , Mahmoud K. H. 
Published: January 2005

AbstractThe dipolar relaxation in poly(vinyl alcohol) (PVA), sodium carboxy methyl cellulose (NaCMCs), and their blends were studied using a thermally stimulated depolarization current (TSDC) technique. The mutual effects of polarization conditions such as heating rate, poling temperature, time, and field on the properties of TSDC were investigated. Quantitative analysis of the experimental data is given in terms of dipolar and space charge polarization. A thermal sampling (TS) technique was applied to decompose the complex relaxations in individual polymers and their blend of 0.5/0.5 wt/wt into its normal distribution components. The activation energy of TS‐formed electrets was determined by fitting the experimental curve to Bucci and Fieschi equations. Peak parameters such as activation energy and preexponential factor τ0 were obtained. A linear relationship between the activation energy and logarithm of the preexponential factor was found, thus confirming operation of the compensation law. In addition, by using the Eyring equation of the rate theory, the activation enthalpy ΔH≠ and the activation entropy ΔS≠ were calculated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1342–1353, 2005
Effects of maleated styrene–(ethylene‐co‐butene)–styrene on the morphology and mechanical and thermal properties of polystyrene/polyamide 1212 blends
Authors: Li Yulin , Xie Tingxiu , Yang Guisheng 
Published: January 2005

AbstractPolystyrene (PS)/polyamide 1212 (PA 1212) blends were compatibilized with a maleated triblock copolymer of styrene–(ethylene‐co‐butene)–styrene (SEBS‐g‐MA). Scanning electron microscopy revealed that the addition of SEBS‐g‐MA was beneficial to the dispersion of PA 1212 in the PS matrix because of the reaction between them. The variation of the fraction of SEBS‐g‐MA in the blends allowed the manipulation of the phase structure, which first formed a sheetlike structure and then formed a cocontinuous phase containing PA 1212/SEBS‐g‐MA core–shell morphologies. As a result, the mechanical properties, especially the Charpy notched impact resistance, were significantly improved with the addition of SEBS‐g‐MA. Differential scanning calorimetry (DSC) data indicated that the strong interaction between SEBS‐g‐MA and PA 1212 in the blends retarded the crystallization of PA 1212. The heat distortion temperature of the compatibilized blends was improved in comparison with that of the unmodified blend, probably because of the apparent increase in the glass‐transition temperature with an increasing concentration of SEBS‐g‐MA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1354–1360, 2005
Influence of the synthesis conditions on the curing behavior of phenol–urea–formaldehyde resol resins
Authors: He Guangbo , Yan Ning 
Published: January 2005

AbstractThe curing behavior of synthesized phenol–urea–formaldehyde (PUF) resol resins with various formaldehyde/urea/phenol ratios was studied with differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The results indicated that the synthesis parameters, including the urea content, formaldehyde/phenol ratio, and pH value, had a combined effect on the curing behavior. The pH value played an important role in affecting the shape of the DSC curing curves, the activation energy, and the reaction rate constant. Depending on the pH value, one or two peaks could appear in the DSC curve. The activation energy was lower when pH was below 11. The reaction rate constant increased with an increase in the pH value at both low and high temperatures. The urea content and formaldehyde/phenol ratio had no significant influence on the activation energy and rate constant. DMA showed that both the gel point and tan δ peak temperature (Ttanδ) had the lowest values in the mid‐pH range for the PUF resins. A different trend was observed for the phenol–formaldehyde resin without the urea component. Instead, the gel point and Ttanδ decreased monotonically with an increase in the pH value. For the PUF resins, a high urea content or a low formaldehyde/phenol ratio resulted in a high gel point. The effect of the urea content on Ttanδ was bigger than that on the gel point because of the reversible reaction associated with the urea component. Too much formaldehyde could lead to more reversible reactions and a higher Ttanδ value. The effects of the synthesis conditions on the rigidity of the cured network were complex for the PUF resins. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1368–1375, 2005