bluuebunny/crossref_metadata_2025_split huggingface dataset:
A miniaturized matrix‐assisted laser desorption/ionization time of flight mass spectrometer with mass‐correlated acceleration focusing
Authors: English Robert D. , Cotter Robert J. 
Published: March 2003

AbstractMass correlated acceleration (MCA) has now been integrated into a 4 in (10.2 cm) matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometer to achieve high resolving power across a broader mass range, without sacrificing detection of higher mass ions. The goal was to combine MCA with a custom‐built miniaturized instrument such as those that might be used for field‐portable applications. Unlike other pulsed extraction methods, MCA is not mass dependent and mass spectra can be achieved with a single tuning of instrument parameters. Additionally, the multi‐channel recording advantage is better realized because ions of all masses can be brought into focus simultaneously. The MCA dual‐stage ion source compensates dynamically for the mass dependence by incorporating an extraction pulse region followed by an acceleration region that contains a time‐dependent waveform correlated with mass. The technique was validated with applications in peptide mixtures and protein digestions. Diagnostic studies for the instrument include m/z range and limits of detection. Copyright © 2003 John Wiley & Sons, Ltd.
Toughness Optimization of SBR Elastomers – Use of Fracture Mechanics Methods for Characterization
Authors: Reincke Katrin , Grellmann Wolfgang , Lach Ralf , Heinrich Gert 
Published: March 2003

AbstractElastomer materials are used in a wide application range and subjected to different loading from which failure of the material results. Because this failure is caused by initiation and propagation of cracks, the application of fracture mechanics methods for the assessment of the material is obvious. A short summary of the methods of technical fracture mechanics including possibilities of determination of crack resistance curves is given. Vulcanizates on the basis of SBR 1500 with various sulfur and carbon black contents were investigated. For describing the crack initiation and crack propagation behavior, several fracture mechanics examination methods were applied. Tear‐analyzer results were used to assess the crack propagation behavior under fatigue‐like loading conditions. Furthermore, for the characterization of the crack resistance of the materials under impact‐like loading conditions, instrumented tensile‐impact tests were performed. To obtain information about the initiation and propagation of a stable crack, quasi‐static fracture mechanics tests were applied. The results of the several tests are discussed in dependence on sulfur and carbon black contents. We found a non‐monotonous behavior of the toughness as a function of carbon black loading. An explanation is given in connection with a percolation‐like transition in filler morphology on larger length scales.
Schematic crack propagation curve for characterizing the fatigue behavior of the vulcanizates recorded in a TFA test.magnified imageSchematic crack propagation curve for characterizing the fatigue behavior of the vulcanizates recorded in a TFA test.
Insertion of Copper(II)/Schiff‐Base Complexes with NLO Properties into Commercial Polycarbonates by Thermal Processes
Authors: Scamporrino Emilio , Bazzano Sebastiano , Vitalini Daniele , Mineo Placido 
Published: March 2003

AbstractThe preparation of a bisphenol‐A carbonate copolymer, containing Cu‐diimine units with nonlinear optical (NLO) properties, and its MALDI‐TOF mass spectrometric characterization are reported. Contrary to the usual synthetic method, NLO groups were inserted directly into a commercial polycarbonate by prolonged heating at 250 °C. This innovative procedure allows to obtain a Cu/diimine‐containing polymer of high molecular weight.
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A time‐based reservation scheme for managing handovers in satellite systems
Authors: Boukhatem L. , Gaïti D. , Pujolle G. 
Published: March 2003

AbstractThis paper proposes a Time‐based Channel Reservation Algorithm (TCRA) suitable for managing handover and call admission control procedures in future mobile satellite systems. These systems are characterized by a high rate of handover attempts which can degrade significantly their performance. Therefore, we propose TCRA, a scheme which guarantees a null handover failure probability by managing the channel through a reservation strategy in the cells to be crossed by the user. Based on the feature that the satellite motion is predictable and deterministic, the scheme tries to maximize the channel utilization and enables the system to handle the most important number of users. The performance of the TCRA scheme has been examined by simulations and compared to the Guaranteed Handover (GH) scheme. The results show the behaviour of the algorithm and its performance. Copyright © 2003 John Wiley & Sons, Ltd.
Ligand‐based computer‐aided pesticide design. A review of applications of the CoMFA and CoMSIA methodologies
Authors: Bordás Barna , Kőmíves Tamás , Lopata Antal 
Published: March 2003

AbstractAn overview is given of the CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) methodologies that are established ligand‐based molecular design tools widely used by medicinal and pesticide chemists. In the absence of a three‐dimensional structure of the target biopolymer, CoMFA and CoMSIA often provide a practical solution to an otherwise intractable problem of proper characterization of ligand–receptor interactions. These techniques are especially important in agrochemistry, where the number of known molecular structures of pesticide targets is limited. The use of CoMFA and CoMSIA in the agrochemical field for modelling the interactions of insecticides, fungicides, herbicides and herbicide safeners with their target binding sites is illustrated by using some selected published work. The CoMFA and CoMSIA models developed have been used successfully to map the properties of unknown receptors, construct hypotheses for ligand–receptor interactions, optimize lead structures, design novel active compounds, and predict biological activities. The application of CoMFA by the present authors for deriving a binding site hypothesis for dichloroacetamide‐type herbicide safeners is described in somewhat more detail.© 2003 Society of Chemical Industry
Standard and Swedish variant types of the hybrid alder Phytophthora attacking alder in Hungary
Authors: Nagy Zoltán Á , Bakonyi József , Érsek Tibor 
Published: March 2003

AbstractA new Phytophthora disease of common alder (Alnus glutinosa) similar to that previously reported in several countries in Europe has been observed in Hungary. Based on these earlier studies, the alder Phytophthora was considered likely to be a hybrid between P cambivora and a P fragariae‐like species: across Europe a range of new alder Phytophthora is spreading that comprise a range of heteroploid hybrids including a ‘standard’ hybrid type and several other hybrid types termed ‘variants’. Phenotypic and molecular features of the pathogen in Hungary were characterised and compared with isolates from elsewhere. The morphologies of five isolates from one region (Hévíz) resembled the common, ‘standard’ type, whereas the three isolates from another region (Hanság) exhibited traits similar to those of one of the ‘variant’ types, ie the Swedish ‘variant’. Molecular markers of these two groups of Hungarian isolates also represented a good fit to those of the standard type and the Swedish variant, respectively. Isozyme patterns and profiles of restriction fragments of the entire internal transcribed spacer (ITS) region or mitochondrial DNAs and of RAPD‐PCR products did not differ within a group, but distinct polymorphisms were exhibited between the two groups of isolates. Southern analysis of random amplified polymorphic DNA (RAPD) revealed the homologous nature of co‐migrating bands of P cambivora and the isolates of alder Phytophthora. Furthermore, restriction fragment profiles of the ITS region of ribosomal DNAs and the mtDNAs were consistent with reported biparental origin of alder Phytophthora. The hybrid status of these continuously evolving pathogens raises many issues and challenges concerning efficient control measures.© 2003 Society of Chemical Industry
Adiabatic Intramolecular Hydrogen Atom Transfer in 2-[2-(2-Pyrrolyl)ethenyl]pyridine
Authors: Obi Masaki , Sakuragi Hirochika , Arai Tatsuo 
Published: March 2003

Abstract
2-[2-(2-Pyrrolyl)ethenyl]pyridine (3) forms an intramolecular hydrogen bond between the pyridine and pyrrole ring and undergoes one-way trans→cis isomerization on direct irradiation. Furthermore, cis isomer undergoes intramolecular hydrogen atom transfer to give a tautomer in the excited singlet state. Based on the experimental findings, effects of intramolecular hydrogen bond and the solvent on the photochemical behaviors of 3 were discussed.
Ga2O3/Al2O3 Prepared by Sol-Gel Method as a Highly Active Metal Oxide-Based Catalyst for NO Reduction by Propene in the Presence of Oxygen, H2O and SO2
Authors: Haneda Masaaki , Kintaichi Yoshiaki , Shimada Hiromichi , Hamada Hideaki 
Published: March 2003

Abstract
Ga2O3/Al2O3 prepared by sol-gel method showed excellent activity for the selective reduction of NO with propene in the presence of H2O, compared with Al2O3, Ga2O3 and impregnated Ga2O3/Al2O3. Its high activity was hardly influenced by the presence of SO2. It was suggested from the results of XPS studies that the presence of gallium oxide interacting strongly with alumina is responsible for the catalytic performance of Ga2O3/Al2O3.
Novel Discrete Structure of Oxalate-bridged Heteronuclear Cr(III)-Nd(III) Complex
Authors: Sakagami Narumi , Okamoto Ken-ichi 
Published: March 2003

Abstract
A novel chromium(III)-neodymium(III) heteronuclear complex has been obtained by utilizing unsym-cis-[Cr(eddp)(ox)]− as a building block. From the X-ray analysis, it is revealed that this complex is tetranuclear in which the Nd(III) ion is bridged by three oxalates in the three Cr(III) units and three water molecules forming a nine-coordinate tricapped trigonal-prism geometry.
Conducting Salts Composed of Selenium Analogues of TMET-TTP
Authors: Mori Takehiko , Ashizawa Minoru , Aragaki Masanobu , Murata Kyoji , Misaki Yohji , Tanaka Kazuyoshi 
Published: March 2003

Abstract
Selenium analogues of TMET-TTP (2-(4,5-bisthiomethyl-1,3-dithiol-2-ylidene)-5-(4,5-ethylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) 1b-d have been synthesized. The iodine salt (1b)4I3 exhibits moderately high conductivity (σrt=13S cm−1) with semiconducting temperature dependence, and the donor arrangement is θ-type. The present θ-type salt as well as TMET-TTP salts is located at the insulating limit in the universal phase diagram of θ-phases.
Hydrogen Transfer in Pt-Mo Heterodinuclear Hydride Complexes Promoted by Alkynes
Authors: Yasuda Toshiyuki , Fukuoka Atsushi , Hirano Masafumi , Komiya Sanshiro 
Published: March 2003

Abstract
Reactions of a Pt-Mo heterodinuclear hydride complex, (dpe)HPt-MoCp(CO)3 with alkynes at room temperature lead to facile reductive elimination giving HMoCp(CO)3 accompanied by the formation of Pt(alkyne)(dpe). When terminal alkynes are employed, further Markovnikov addition of HMoCp(CO)3 to the coordinated alkyne takes place to give new heterodinuclear alkenyl complexes (dpe)(μ-H2C=CR)Pt-MoCp(μ-CO)(CO).
Self-Assembly and X-ray Structure Determination of the Novel 2-D Layered Organic–Inorganic Hybrid Pb–X Compound: [PbX2(4,4′-bipy)]n (X = I, Br)
Authors: Shi Yu-Jun , Xu Yan , Zhang Yong , Huang Bin , Zhu Dun-Ru , Jin Chuan-Ming , Zhu Hao-Guo , Yu Zhi , Chen Xue-Tai , You Xiao-Zeng 
Published: March 2003

Abstract
Two novel organic–inorganic hybrid compounds, [PbI2(4,4′-bipy)]n (1) and [PbBr2(4,4′-bipy)]n (2), are synthesized by self-assembly. X-ray crystallography analysis shows that the [PbI2]n chains in 1 are linked by 4,4′-bipyridine to form a layer, via Pb–N bonding along the direction of the ‘b’ axis.
Electrochemically Regulated Iron Uptake and Release for Ferritin Immobilized on Self-Assembled Monolayer-Modified Gold Electrodes
Authors: Tominaga Masato , Taniguchi Isao 
Published: March 2003

Abstract
Horse spleen ferritin was immobilized on self-assembled monolayers (SAMs)-modified gold electrodes by electrostatic interaction. Electrochemically regulated iron uptake and release for the ferritin immobilized on the electrode was demonstrated.
Chemoselective Reduction of α-Imino Carbonyl Compounds into α-Amino Carbonyl Compounds with Titanium Tetraiodide
Authors: Shimizu Makoto , Sahara Tetsuya , Hayakawa Ryuuichirou 
Published: March 2003

Abstract
α-Imino carbonyl compounds are chemoselectively reduced with titanium tetraiodide to give α-amino carbonyl compounds in good to excellent yields
Multiple Fabrications of Crystalline CdS Thin Films from a Single Bath by EICD in Acidic Aqueous Solution of Cd2+ and Thiourea Complex
Authors: Yamaguchi Koichi , Mukherjee Pragati , Yoshida Tsukasa , Minoura Hideki 
Published: March 2003

Abstract
Multiple fabrications of crystalline CdS thin films have been realized by electrochemically induced chemical deposition (EICD) from a single acidic aqueous bath of stable Cd2+–thiourea complexes. Repeated depositions up to five times from the same bath have been proven to yield CdS thin films with essentially the same quality and thickness, owing to the absence of chemical decomposition of the precursor.
Surface-Mediated Solid Phase Reactions: A Simple and New Method for the Synthesis of α-Aminophosphonates under Solvent-Free Conditions
Authors: Kaboudin Babak 
Published: March 2003

Abstract
Alumina-supported ammonium formate was found to be an efficient reagent for the synthesis of 1-aminophosphonates from aldehydes and diethyl phosphite. This method is an easy, rapid and high-yielding reaction for the synthesis of 1-aminophosphonates.
A TiO2-Suspended Continuous Flow Photoreactor System Combined with the Separation of TiO2 Particles by Coagulation for the Photocatalytic Degradation of Dibutyl Phthalate
Authors: Hasegawa Kiyoshi , Ito Tomonori , Maeda Miyoko , Kagaya Shigehiro 
Published: March 2003

Abstract
A TiO2-suspended continuous flow photoreactor system combined with the separation of TiO2 particles by coagulation was applied for the photocatalytic degradation of dibutyl phthalate (DBP). The system enabled the efficient degradation of DBP and the continuous discharge of transparent water.
Mechanistic Study of the Ru(H)2(CO)(PPh3)3-Catalyzed Addition of C–H Bonds in Aromatic Esters to Olefins
Authors: Kakiuchi Fumitoshi , Ohtaki Hisashi , Sonoda Motohiro , Chatani Naoto , Murai Shinji 
Published: March 2003

Abstract
The reaction mechanism of the Ru(H)2(CO)(PPh3)3-catalyzed addition of C–H bonds in aromatic esters to olefins was studied by means of deuterium-labeling experiments and measurement of the 13C kinetic isotope effect. The deuterium-labeling experiment revealed a rapid equilibrium among the intermediates prior to the reductive elimination, and the 13C NMR kinetic isotope effect indicated that C–C bond formation is the rate-determining step in this reaction.
Polynucleotide Can Stabilize Nucleobase-appended Cholesterol Gels
Authors: Numata Munenori , Shinkai Seiji 
Published: March 2003

Abstract
The influence of added poly(A) or poly(C) on the gelation ability of uracil-appended cholesterol gelator was investigated. It was found that RNA-gelator complexes were formed in n-butanol solution. In particular, complementary poly(A) not only stabilized the gel system but also created the helical structure in the original gel phase.
Substituent Effect in Amine-CO2 Interaction Investigated by NMR and IR Spectroscopies
Authors: Yoon Sang Jun , Lee Huen 
Published: March 2003

Abstract
The donor property changes of amines by methyl or hydroxyl substituents were studied by NMR and FT-IR spectroscopies. This fundamental investigation can contribute for identifying CO2 absorption capacity of amine solution mainly due to electron releasing and withdrawing effects of substituents.
Crystallographic report: Bis(O‐methoxyethyldithiocarbonato)(4,7‐dimethyl‐1,10‐phenanthroline)cadmium(II)
Authors: Chen Danlin , Lai Chian Sing , Tiekink Edward R. T. 
Published: March 2003

AbstractThe structure of mononuclear Cd(S2COCH2CH2OCH3)2(4,7‐Me2phen) shows an N2S4 donor set about cadmium that defines a coordination geometry intermediate between octahedral and trigonal prismatic. Copyright © 2003 John Wiley & Sons, Ltd.
Crystallographic report: (2,9‐Dimethyl‐1,10‐phenanthroline)bis‐(N,N‐pyrrolidinedithiocarbamato)zinc(II) chloroform hemihydrate
Authors: Sing Lai Chian , Tiekink Edward R. T. 
Published: March 2003

AbstractThe mononuclear structure of Zn(S2C(N(CH2)2)4)2(2,9‐Me2‐1,10‐phen) shows monodentate coordination by the dithiocarbamate ligands and a distorted tetrahedral geometry for zinc, defined by an N2S2 donor set, results. Copyright © 2003 John Wiley & Sons, Ltd.
A Stereoselective and Short Total Synthesis of the Polyhydroxylated γ‐Amino Acid (−)‐Detoxinine, Based on Stereoselective Preparation of Dihydropyrrole Derivatives from Lithiated Alkoxyallenes
Authors: Flögel Oliver , Okala Amombo Marlyse Ghislaine , Reißig Hans‐Ulrich , Zahn Gernot , Brüdgam Irene , Hartl Hans 
Published: March 2003

AbstractBased on our earlier results employing lithiated methoxyallene 2 as C3 building block and imines 3 for the synthesis of dihydropyrrole derivatives 5, we have investigated chiral imines 6, 10, and 15 as electrophilic components. Combined with lithiated alkoxyallenes, these imines provide the corresponding primary adducts and finally the dihydropyrrole derivatives 8, 12, 17, 20, and 22 in good yields and with high to excellent syn selectivities. This stereochemical outcome is interpreted as a result of α‐chelate control. Treatment with hydrochloric acid converted syn‐8 and syn‐12 into bicyclic compounds 9 and 13, whereas under more mildly acidic conditions adduct syn‐17 was transformed into diol syn‐18. The total synthesis of the uncommon γ‐amino acid (−)‐detoxinine could be achieved by starting from (S)‐malic acid, which was converted into imine 15 in four steps. Lithiated benzyloxyallene added to imine 15 and efficiently furnished the crucial dihydropyrrole derivative syn‐22. The hydrogenolysis of this compound did not directly provide the protected triol 29 as anticipated, but a stepwise protocol made the triol available in a fairly satisfactory manner. A second crucial step of the synthesis was the selective oxidation of 29, which could be achieved by employing platinum dioxide and oxygen. The resulting bicyclic lactone 30 was smoothly transformed into enantiopure (−)‐detoxinine. Thus, a fairly short synthesis of this natural product based on a lithiated alkoxyallene could be performed, demonstrating the potential of these intermediates for syntheses of interesting functionalized heterocyclic compounds.
Cover Picture: Direct Observation of Charge‐Transfer Reactions in Nanoscopic Test Tubes: Self‐Ionization in HNO3 Clusters (ChemPhysChem 3/2003)
Authors: Gebhardt Christoph R. , Witte Thomas , Kompa Karl L. 
Published: March 2003

AbstractThe cover picture shows schematically the release of charge carriers from a molecular cluster via cluster fragmentation caused by a surface collision. In the incoming cluster, which is neutral as a whole, a charge‐transfer reaction has previously generated equal numbers of positive‐ and negative‐charge carriers. The subsequent fragmentation now breaks the cluster apart and forms mass‐spectrometrically observable free charge carriers, represented here by the blue and the red sphere. Thus, surface collisions of large molecular clusters allow the direct observation of bulk‐phase charge‐transfer processes by mass spectrometry. Find out more in the communication by Gebhardt et al. on pp. 308–312.
Palladium‐Catalyzed SN1 Reactions of Secondary Benzylic Alcohols: Etherification, Amination, and Thioetherification
Authors: Miller Kimberly J. , Abu‐Omar Mahdi M. 
Published: March 2003

AbstractThe reaction of various secondary benzylic alcohols in the presence of PdII catalysts provides ethers in good to high yields. Unsymmetric ethers could also be obtained with good selectivity by coupling two different alcohols. Direct amination is observed with electron‐deficient anilines, and thioethers are prepared conveniently in high yields by the direct action of thiols on sec‐phenylethyl alcohol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Transitivity, flexibility, conjunctive representations, and the hippocampus. II. A computational analysis
Authors: Frank Michael J. , Rudy Jerry W. , O'Reilly Randall C. 
Published: March 2003

AbstractA computational neural network model is presented that explains how the hippocampus can contribute to transitive inference performance observed in rats (Dusek and Eichenbaum, 1997. Proc Natl Acad Sci U S A 94:7109–7114; Van Elzakker et al., 2003. Hippocampus 12:this issue). In contrast to existing theories that emphasize the idea that the hippocampus contributes by flexibly relating previously encoded memories, we find that the hippocampus contributes by altering the elemental associative weights of individual stimulus elements during learning. We use this model to account for a range of existing data and to make a number of distinctive predictions that clearly contrast these two views. Hippocampus 2003;13:341–354. © 2003 Wiley‐Liss, Inc.