bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous Formation of Ordered Lateral Patterns in Polymer Thin‐Film Structures
Authors: Okayasu T. , Zhang H.‐L. , Bucknall D. G. , Briggs G. A. D. 
Published: November 2004

AbstractThe understanding of the lateral morphology stability of thin polymer devices is of fundamental importance. In this work, the lateral morphology in a model system consisting of thin polymer films capped with thin metal layers on a Si substrate is investigated. When the model system is heated above a critical temperature, a characteristic surface topographic structure is observed that has a well‐defined periodicity but random orientation. It is shown that the minimum temperature, Tmin, required for the surface pattern to be observed decreases with increasing polymer‐film thickness. Increasing either the metal‐ or polymer‐layer thickness increases the characteristic wavelength of the topography. It is believed that the dominating driving force for the surface corrugated‐pattern formation is the thermal‐expansion‐coefficient mismatch of the capping layer and the substrate. A theoretical model based on local bending of a thin, stiff surface film on a thin, elastic medium is used to provide a quantitative analysis of the surface morphology. The calculated minimum temperature required for the surface morphology and the periodicity of the surface patterns to form are in strong agreement with the experimental results. By contrast, systems with prefabricated topographic patterns within any of the three layers (polymer, metal, substrate) produce highly anisotropic surface topographies aligned perpendicular to the prefabricated topographic structure. It is also found that, in a model system with pre‐patterned polymer films, a much higher critical temperature is required for the surface morphology to be observed. The changes in apparent stability and morphological orientation in the pre‐patterned systems can be understood as a result of the anisotropic release of the lateral surface stress during the heat treatment.
A Biomimetic Artificial Disc with Improved Mechanical Properties Compared to Biological Intervertebral Discs
Authors: Shikinami Y. , Kotani Y. , Cunningham B. W. , Abumi K. , Kaneda K. 
Published: November 2004

AbstractPatients with serious spinal disc disorders will benefit from a novel artificial disc system that is suitable for clinical use in replacement arthroplasty. The disc is composed of a biomimetic three‐dimensional (3D) fabric with a triaxial fiber alignment that has superior mechanical properties when compared to conventional implants. This disc improves on the constitutional imperfections of biological intervertebral discs by eliminating the risk of rupture and delamination. The fabric bonds firmly to disc bodies, and functions in combination with bioactive bioresorbable pins and scaffolds as a stand‐alone system that maintains the position of the disc and promotes bone growth at the interface. The disc has high biocompatibility and can maintain biomimetic “J‐shaped” stress–strain behavior for up to sixty‐three million alternating stresses, which is the equivalent of natural biological movements for a period of more than 30 years. This technology exemplifies how, in the best biomaterials, biological flexibility may occasionally overcome artificial rigidity.
Extracting Parameters from the Current–Voltage Characteristics of Organic Field‐Effect Transistors
Authors: Horowitz G. , Lang P. , Mottaghi M. , Aubin H. 
Published: November 2004

AbstractOrganic field‐effect transistors were fabricated with vapor‐deposited pentacene on aluminum oxide insulating layers. Several methods are used in order to extract the mobility and threshold voltage from the transfer characteristic of the devices. In all cases, the mobility is found to depend on the gate voltage. The first method consists of deriving the drain current as a function of gate voltage (transconductance), leading to the so‐called field‐effect mobility. In the second method, we assume a power‐law dependence of the mobility with gate voltage together with a constant contact resistance. The third method is the so‐called transfer line method, in which several devices with various channel length are used. It is shown that the mobility is significantly enhanced by modifying the aluminum oxide layer with carboxylic acid self‐assembled monolayers prior to pentacene deposition. The methods used to extract parameters yield threshold voltages with an absolute value of less than 2 V. It is also shown that there is a shift of the threshold voltage after modification of the aluminum oxide layer. These features seem to confirm the validity of the parameter‐extraction methods.
Understanding the Origin of the 535 nm Emission Band in Oxidized Poly(9,9‐dioctylfluorene): The Essential Role of Inter‐Chain/Inter‐Segment Interactions (Adv. Funct. Mater. 2004, 14, 765–781)
Authors: Sims M. , Bradley D. D. C. , Ariu M. , Koeberg M. , Asimakis A. , Grell M. , Lidzey D. G. 
Published: November 2004

AbstractTo view the original paper use http://dx.doi.org/10.1002/adfm.200305149">.
Synthetic Approach to Substituted Cyclopropanes Based on the Coupling Reaction of Lithiated Chloroalkyloxazolines with Fischer Carbene Complexes.
Authors: Florio Saverio , Perna Filippo M. , Luisi Renzo , Barluenga Jose , Rodriguez Felix , Fananas Francisco J. 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Electrochemical Partial Fluorination of Organic Compounds. Part 74. Efficient Anodic Synthesis of 2‐Fluoro‐ and 2,3‐Difluoro‐2,3‐dihydrobenzofuran Derivatives.
Authors: Dawood Kamal M. , Fuchigami Toshio 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of Novel Condensed Binuclear Heterocycles Based on 1,3‐ and 1,5‐Dicarbonyl Derivatives of 2,2‐Dimethyltetrahydropyran.
Authors: Zyk N. V. , Vatsadze S. Z. , Kostochka M. L. , Lezina V. P. , Vinokurov V. G. 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis and Study of the Properties of 7,8‐Polymethyleneimidazo[4,5‐d]‐1,3,2‐diazaphosphorin‐2‐thiones.
Authors: Nilov D. B. , Kadushkin A. V. , Solov'eva N. P. , Sheinker Yu. N. , Granik V. G. 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Novel Stereoselective Entry to 2′‐β‐Carbon‐Substituted 2′‐Deoxy‐4′‐thionucleosides from 4‐Thiofuranoid Glycals.
Authors: Haraguchi Kazuhiro , Shiina Noriaki , Yoshimura Yuichi , Shimada Hisashi , Hashimoto Kyoko , Tanaka Hiromichi 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthetic, Structural, and Mechanistic Issues in the Development of a Subtype Selective GABA Partial Agonist Hypnotic Agent
Authors: Ragan John A. , Murry Jerry A. , Castaldi Michael J. , Conrad Alyson K. , Hill Paul D. , Jones Brian P. , Kasthurikrishnan Narasimhan , Li Bryan , Makowski Teresa W. , McDermott Ruth , et al. et al. 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis and Structural Characterization of Three‐Coordinate MnII, FeII, and ZnII Complexes Containing a Bulky Diamide Ligand [DippN(CH2)3NDipp]2− (Dipp = 2,6‐iPr2C6H3)
Authors: Chai Jianfang , Zhu Hongping , Ma Qingjun , Roesky Herbert W. , Schmidt Hans‐Georg , Noltemeyer Mathias 
Published: November 2004

AbstractThe reaction of DippNH(CH2)3NHDipp (1) (Dipp = 2,6‐iPr2C6H3) with 2 equiv. of MeLi in diethyl ether resulted in the formation of the monomeric dilithium salt [(Dipp)N(CH2)3N(Dipp)][Li(OEt2)]2 (2) in high yield. Further reactions of 2 with MnCl2, FeCl2, and ZnCl2, respectively, afforded the complexes [M2{N(Dipp)(CH2)3N(Dipp)}2] [M = Mn (3), Fe (4), Zn (5)] with three‐coordinate metal centers. Complexes 2−5 were characterized by X‐ray structural analysis. The complexes contain a nonplanar MNMN central core. The diamide ligand in complexes 3−5 displays a boat conformation and is both chelating and bridging, so that one of the nitrogen atoms is three‐coordinate and the other four‐coordinate. Complexes 3−5 are the first examples with diamide ligands in such a bonding mode. The magnetic investigations of compounds 3 and 4 reveal an antiferromagnetic exchange between the metal atoms. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Apparent Allyl Rotation and Pd−N Bond Rupture in Allylpalladium Complexes with N‐Donor Ligands − Evidence of an Associative Mechanism
Authors: Jalón Félix A. , Manzano Blanca R. , Moreno‐Lara Belén 
Published: November 2004

AbstractThe new didentate N‐donor ligands 2‐(4‐methyl‐1H‐pyrazol‐1‐yl)pyrimidine (4Me‐pzpm, 1) and 2‐(4‐bromo‐1H‐pyrazol‐1‐yl)pyrimidine (4Br‐pzpm, 2) have been synthesised and used to obtain the allylpalladium derivatives [Pd(η3‐2Me‐C3H4)(NN′)]X [X = BAr′4−, NN′ = 1 (3), NN′ = 2 (4); X = CF3SO3−, NN′ = 1 (5), NN′ = 2 (6)]. In complexes 3−6 two types of fluxional process have been found: apparent allyl rotation that is observed as Hsyn−Hsyn, Hanti−Hanti interconversions and H4−H6 interchange of the pyrimidine protons that must involve Pd−N(pm) bond rupture. The influence of different factors on both processes — such as the nature of the N‐donor ligand, counterion, solvent, complex concentration and addition of water — has been studied. It has been concluded that the apparent allyl rotation has a lower free energy of activation and in both cases the presence of a species with coordinating ability favours the process. Negative entropies of activation have been found. Associative mechanisms involving participation of five‐coordinate intermediates have been proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Hidden Equilibrium in Aqueous Sodium Carbonate Solutions − Evidence for the Formation of the Dicarbonate Anion
Authors: Zeller Klaus‐Peter , Schuler Paul , Haiss Peter 
Published: November 2004

AbstractCrossover 13C NMR experiments between [13C]carbonate and [18O]carbonate in aqueous solution confirm the combined action of two oxygen‐exchange modes. The isotopomeric carbon dioxides formed in the hydrolysis equilibrium of the labeled carbonate anions react with hydroxide with formation of hydrogencarbonate and with isotopomeric carbonate anions yielding the corresponding dicarbonate species, which, in the back reaction, form carbon dioxide and carbonate anions with distributed oxygen. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Columnar Mesomorphism in Hexacatenar Tetrahedral (2,2′‐Bipyridine)zinc Complexes and Homologous Palladium Derivatives
Authors: Barberio Giovanna , Bellusci Anna , Crispini Alessandra , Ghedini Mauro , Golemme Attilio , Prus Piotr , Pucci Daniela 
Published: November 2004

AbstractThe synthesis and characterisation of novel liquid crystals which display columnar mesomorphism induced upon complexation of a series of nonmesomorphic hexacatenar 4,4′‐disubstituted 2,2′‐bipyridines (Ln) are reported. The introduction of different metal centres (Zn, Pd) causes the appearance of mesomorphism in all complexes regardless of the geometry around the metal ion. We therefore report the first examples of mesomorphism in tetrahedral zinc derivatives. The nature of the columnar phases is related to the self‐assembly of the half‐disc shaped [LnMCl2] (M = Zn, Pd) complexes into full disc‐shaped supramolecules. The molecular organisation in the mesophase is mainly driven by intermolecular attractive interactions, as shown by the crystal structure of the model compound [LPdCl2]. Preliminary measurements of photoconductivity have been performed on samples of [LnMCl2] complexes doped with C60 to increase absorption. Promising results were obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Structural and Photophysical Characterisation of fac‐[Tricarbonyl(chloro)(5,6‐epoxy‐1,10‐phenanthroline)rhenium(I)]
Authors: Martí Angel A. , Mezei Gellert , Maldonado Lorena , Paralitici Giovanni , Raptis Raphael G. , Colón Jorge L. 
Published: November 2004

AbstractThe structural and spectroscopic characterisations of fac‐[Re(phen)(CO)3Cl] (1) (phen = 1,10‐phenanthroline), fac‐[Re(ephen)(CO)3Cl] (3) [ephen = 5,6‐epoxy‐1,10‐phenanthroline (2)] and ephen are reported. The appearance of weak hydrogen bond networks in the crystal lattice of [Re(ephen)(CO)3Cl] and ephen are discussed. Two different isomers of [Re(ephen)(CO)3Cl] were identified by IR and NMR spectroscopy. Coincidental resonances were differentiated for these complexes by temperature‐dependent NMR spectroscopy. Recrystallisation of the crude material allowed the separation of the two isomers. The spectroscopic data permitted the calculation of radiative and nonradiative luminescence rate constants which are consistent with the energy gap law. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Fmoc‐Assisted Synthesis of a 29‐Residue Cystine‐Knot Trypsin Inhibitor Containing a Guaninyl Amino Acid at the P1‐Position
Authors: Avrutina Olga , Schmoldt Hans‐Ulrich , Kolmar Harald , Diederichsen Ulf 
Published: November 2004

AbstractAn Fmoc‐assisted synthesis of a 29 amino acid trypsin inhibitor (McoTI‐29) is presented, which contains a non‐natural guaninyl nucleo amino acid as arginine mimetic at the P1 position. This artificial amino acid functions as a conformational restricted arginine isoster with reduced basicity. The folded cyclotide McoTI‐II open‐chain variant McoTI‐29 has been synthesized from a linear precursor by in situ oxidation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Conformational Analysis of Saturated trans‐Fused 1,3,2‐Benzoxazaphosphinine 2‐Oxides − DFT Calculation of NMR J(P,H) Coupling Constants
Authors: Tähtinen Petri , Bagno Alessandro , Koch Andreas , Pihlaja Kalevi 
Published: November 2004

AbstractThe 3JP,H and 4JP,H spin‐spin coupling constants of a selected test set of organophosphorus compounds, calculated by density functional theory (DFT) methods, were found to correlate well with the experimentally measured coupling constants. The contribution of the spin‐dipole (SD) term to the coupling constants was found to be negligible, and the diamagnetic and paramagnetic spin‐orbit (DSO and PSO) terms cancelled each other, as in the case of JH,H. Calculation solely of the Fermi contact (FC) term was found to be sufficient to provide good estimates of the coupling constants. In the second part of the work, the conformational equilibria and coupling constants in 2‐bis(2‐chloroethyl)amino‐trans‐octahydro‐2H‐1,3,2‐benzoxazaphosphinine 2‐oxide and its 3‐methyl derivative were studied. DFT methods failed in predicting the relative stabilities of the conformations but yielded good geometries and coupling constants. Optimization of the conformations at the Møller‐Plesset second‐order perturbation theory (MP2) level resulted in energy differences compatible with previous experimental observations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Linear Fused Pyran‐Dioxane‐Cyclohexane Tricycles: Synthesis of the Five Linkage Isomers and Ensuing Reactions
Authors: Lichtenthaler Frieder W. , Cuny Eckehard 
Published: November 2004

AbstractA systematic investigation of the mono‐O‐glycosylation of meso‐, (S,S)‐, and (R,R)‐cyclohexane‐1,2‐diol with the D‐glucose‐derived 2‐ketohexosyl bromide 5 is presented. In each instance, simple Königs−Knorr conditions not only elicit the exclusive formation of the respective β‐2‐ketoglycosides, but also effect their subsequent intramolecular hemiketalization to provide tricycles with a 1,5,10‐trioxa‐perhydroanthracene framework. The linkage geometries of the products − two each from the meso‐ (→ 10, 12) and (S,S)‐diols (→ 16, 17), and only one from the (R,R)‐isomer (→ 26) − are determined in the hemiketalization step by an interplay of the anomeric effect and steric factors, favoring those isomers in which the pyran ring oxygen and the ketal‐OH are in a trans‐diaxial disposition. The most propitious case with respect to uniformity of reaction and yield (87%) turned out to the (R,R)‐diol‐derived cis‐cisoid‐trans‐fused 26 as steric and stereoelectronic factors operate concertedly in the hemiketalization step. In each of these pyran‐dioxane‐cyclohexane tricycles, the acetalic hydroxyl group could be removed by BF3‐mediated reduction with triethylsilane, the 1H NMR spectroscopic data of the respective products 14, 15, 18 and 28 being instrumental in assigning their linkage geometries. Slightly basic conditions (nBu4NOAc in acetonitrile) elicit highly stereoselective rearrangements in the pyran ring, for example 16 → 23 and 26 → 30; the tricycles have the structurally and stereochemically correct framework of a variety of cardenolides, in which a 2‐ketosugar is doubly linked to a steroidal aglycon‐diol. Thus, the methodology elaborated here shows high promise to provide a first, preparatively satisfactory access to this type of cardiac glycosides as well as to spectinomycin type antibiotics. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Why do Electron‐Deficient Dienes React Rapidly in Diels−Alder Reactions with Electron‐Deficient Ethylenes? A Density Functional Theory Analysis
Authors: Domingo Luis R. 
Published: November 2004

AbstractThe Diels−Alder reaction of the electron‐deficient (ED) dimethyl 2,3‐dimethylenesuccinate with two electron‐rich (ER) and two ED ethylenes has been studied at the B3LYP/6‐31G* level of theory. The analysis of the geometry and electronic structure of the transition state of the reaction with the ED dimethyl 2‐methylenemalonate along with the analysis of the global and local electrophilicity indices of the reagents provide an explanation of the participation of this ED diene as nucleophile against powerful electrophiles in polar Diels−Alder reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Modeling environmental data by functional principal component logistic regression
Authors: Escabias M. , Aguilera A. M. , Valderrama M. J. 
Published: November 2004

AbstractIn recent years, many studies have dealt with predicting a response variable based on the information provided by a functional variable. When the response variable is binary, different problems arise, such as multicollinearity and high dimensionality, which prejudice the estimation of the model and the interpretation of its parameters. In this article we address these problems by using functional logistic regression and principal component analysis. In order to obtain a unique solution for the maximum likelihood estimation of the parameter function, quasi‐natural cubic spline interpolation of sample paths on their discrete time observations is proposed. We also introduce a new interpretation of the relationship between the response variable and the functional predictor where the change in the odds of success is evaluated from the estimated parameter function. An analysis of climatological data is finally presented to illustrate the practical performance of the proposed methodologies. Copyright © 2004 John Wiley & Sons, Ltd.
Mammalian cell delivery via aerosol deposition
Authors: Veazey William. S. , Anusavice Kenneth J. , Moore Karen 
Published: November 2004

AbstractThe objective of this study was to test the hypothesis that bovine dermal fibroblasts can survive aerosol delivery via an airbrush with mean cell survival rates greater than 50%. This technology has great implications for burn and other wound therapies, for delivery of genetically altered cells in gene therapies, and for tissue engineering with tissue scaffolds. Bovine dermal fibroblasts were suspended at a concentration of 200,000 cells/mL in Hank's Balanced Salt Solution, and delivered into six‐well tissue culture plates using a Badger 100G airbrush. Cells were delivered through three nozzle diameters (312, 484, and 746 μm) at five different air pressures (41, 55, 69, 96, and 124 kPa). Nine repetitions were performed for each treatment group, and cell viability was measured using trypan blue exclusion assay. Mean cell viability ranged from 37 to 94%, and depended on the combination of nozzle diameter and delivery pressure (p < 0.0001). Linear regression analysis was used to develop a stochastic model of cell delivery viability as a function of nozzle diameter and delivery air pressure. This study demonstrates the feasibility of using an airbrush to deliver viable cells in an aerosol to a substrate. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 334–338, 2005
Trafficking and localization of platinum complexes in cisplatin‐resistant cell lines monitored by fluorescence‐labeled platinum
Authors: Liang Xing‐Jie , Shen Ding‐Wu , Chen Kevin G. , Wincovitch Stephen M. , Garfield Susan H. , Gottesman Michael M. 
Published: November 2004

AbstractCisplatin is a chemotherapeutic agent commonly used in the treatment of a wide variety of malignant tumors. Resistance to cisplatin represents a major obstacle to effective cancer therapy because clinically significant levels of resistance quickly emerge after treatment. Based on previous studies indicating abnormal plasma membrane protein trafficking in cisplatin‐resistant (CP‐r) cells, Fluorescence (Alexa Fluor)‐labeled cisplatin was used to determine whether this defect altered the trafficking and localization of cisplatin by comparing drug sensitive KB‐3‐1 and KB‐CP‐r cells. Alexa Fluor–cisplatin was readily internalized and localized throughout the KB‐3‐1 cells, but overall fluorescence decreased in KB‐CP‐r cells, as detected by flow cytometry (FACS) and confocal microscopy. Only punctate cytoplasmic staining was observed in KB‐CP‐r cells with less fluorescence observed in the nucleus. Colocalization experiments with a Golgi‐selective stain indicate the involvement of Golgi‐like vesicles in initial intracellular processing of Alexa Fluor conjugated cisplatin complexes. As detected using an antibody to Alexa Fluor–cisplatin, cisplatin complex‐binding proteins (CCBPs) were reduced in membrane fractions of single‐step cisplatin‐resistant KB‐CP.5 cells, and increased in the cytoplasm of KB‐CP.5 cells compared to KB‐3‐1 cells. CCBPs localized to lower density fractions in KB‐CP.5 cells than in KB‐3‐1 cells as determined by iodixanol gradient centrifugation. In summary, inappropriate trafficking of CCBPs might explain resistance to cisplatin in cultured cancer cells, presumably because membrane binding proteins for cisplatin are not properly located on the cell surface in these cells, but are instead trapped in low density vesicles within the cytoplasm. © 2004 Wiley‐Liss, Inc.