bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Crystalline Behavior of α-Substituted Oligothiophenes
Authors: Yamada Takashi , Azumi Reiko , Tachibana Hiroaki , Sakai Hideki , Abe Masahiko , Bäuerle Peter , Matsumoto Mutsuyoshi 
Published: April 2003

Abstract
Thermal behaviors of α-disubstituted oligothiophenes were investigated. 5,5″-Dicyanoterthiophene having thiophene rings as the rigid core exhibited a nematic liquid crystalline phase at 205 °C on cooling. It should be emphasized that this molecule lacks in a flexible substituent such as a long alkyl chain.
NO Reduction by CH4 over Well-Structured Pt Nanocrystal Supported on γ-Al2O3
Authors: Balint Ioan , Miyazaki Akane , Aika Ken-ichi 
Published: April 2003

Abstract
Platinum nanocrystals, having mainly (100) structure, have been prepared by a colloid method and then supported on γ-Al2O3. The catalytic test of Pt(100)/Al2O3 for the NO/CH4 reaction showed that the formation of NH3 and CO side products was prevented in contrast to the conventional Pt/γ-Al2O3 catalyst that gives relatively high selectivity to NH3 and CO.
Hybrid Inorganic–Organic Material Containing 12-Molybdophosphate Bulk-Modified Carbon Paste Electrode
Authors: Wang Xiuli , Wang Enbo , Hu Changwen 
Published: April 2003

Abstract
The hybrid inorganic–organic electroactive material containing 12-molybdophosphate was synthesized and firstly used as a bulk-modifier to fabricate a chemically modified carbon paste electrode (CPE). The hybrid material bulk-modified CPE (HM-CPE) exhibits stable electrochemical behavior and good electrocatalytic activity. The remarkable advantage of the HM-CPE is its excellent reproducibility of surface renewal.
Histidine and Thermal Copolymers of Amino Acids Containing Histidine as Prebiotic Inhibitor for the Template-Directed Formation of Oligoguanylate on a Poly(C) Template
Authors: Kawamura Kunio , Kuranoue Kazuhiro 
Published: April 2003

Abstract
Possibility of the cooperative chemical evolution of nucleic acids and proteins has been investigated using the template-directed formation of oligoguanylate with amino acids and thermal copolymers of amino acids, in which strong inhibition by histidine containing thermal copolymer and histidine itself was observed. The inhibition is regarded as prebiotic enzymatic activities for the hydrolysis of activated nucleotide monomer and the formation of pyrophospho-capped oligoguanylate.
Synthesis of a New Tridentate Anthracene Ligand Bearing (i-Pr)2P Group at 1,8-Positions: Facile Bond Switch on Tetracoordinate Boron Atom
Authors: Yamashita Makoto , Watanabe Kentaro , Yamamoto Yohsuke , Akiba Kin-ya 
Published: April 2003

Abstract
9-Borylanthracene 12 was prepared from 1,8-bis(diisopropylphosphino)-9-bromoanthracene (5) and the X-ray structure of 12 shows a tetrahedral boron atom coordinated by only one of the two (i-Pr)2P groups. However, anthracene protons were observed symmetrically in 1H NMR even at −80 °C, clearly indicating that the intramolecular bond-switching process is taking place very rapidly in solution.
A Novel Self-Assembled Porphyrin Polymer Constructed by a Pd(II)–Pyridine Interaction
Authors: Ikeda Atsushi , Ayabe Masatsugu , Shinkai Seiji 
Published: April 2003

Abstract
A novel self-assembled polymer, which has a fibrous structure with enough long and many large inside cavities, was constructed by a pyridine–Pd(II) interaction from one mole of pyridine-containing porphyrin derivative and four moles of Pd(II) complex.
Synthesis and Characterization of a New Layered Zinc Phosphate: (C3H4N2)3Zn4(HPO4)(PO4)2 with Imidazole Coordinating to Zn Atoms
Authors: Cui Aili , Yao Youwei 
Published: April 2003

Abstract
A new two-dimensional hybrid zinc phosphate with electro-neutral open-framework has been hydrothermally synthesized by using imidazole as a structure-directing agent, whose structure is characterized with 3-, 4-, 5-, and 12-ring layers and coordination bonds between imidazole groups and zinc atoms, resulting in primary building units of ZnO2N2 and ZnO3N.
Surface Modification of Aluminosilicate Nanofiber “Imogolite”
Authors: Yamamoto Kazuya , Otsuka Hideyuki , Wada Shin-Ichiro , Takahara Atsushi 
Published: April 2003

Abstract
The nanostructure of natural aluminosilicate nanofiber “imogolite” under acidic conditions was directly confirmed by observation with atomic force microscope (AFM) for the first time. The outer surface of imogolite was successfully hydrophobidized by chemisorption of a phosphonic acid derivative with an alkyl chain.
New Insulinomimetic Zinc(II) Complexes of Nicotinamide and its Derivatives: X-ray Structure and Biochemical Activity
Authors: Ueda Eriko , Yoshikawa Yutaka , Kishimoto Noriko , Tadokoro Makoto , Yanagihara Naohisa , Sakurai Hiromu , Kojima Yoshitane 
Published: April 2003

Abstract
Three Zn(II) complexes with nicotinamide(na), nicotinemethylamide(nma), and nicotineethylamide(nea) were found to have in vitro insulinomimetic activities. X-ray structure analysis of [Zn(nea)2(H2O)2(SO4)]n showed that each nitrogen atom of two nea molecules locates trans, and the two water molecules and each oxygen atom of the two sulfates coordinate to a Zn(II) ion, forming an octahedral geometry of Zn(N2O4) unit in an inorganic polymer crystal. The Zn(II) complexes with na, nma, and nea exhibited higher insulinomimetic activities, respective IC50 values (50% inhibition concentration of the complex in the free fatty acids release from rat adipocytes) being 1.34, 1.12, and 0.96 mM, than that of ZnSO4 (IC50 = 1.52 mM).
Solid-State Specific and Unidirectional Photoisomerization of 3-Substituted Propyl to 1-Substituted Propyl Cobaloxime Complexes via 2-Substituted Propyl Complexes
Authors: Ohgo Yoshiaki , Kurashima Futoshi , Hiraga Yoshito , Ishida Kanako , Takatsu Naoko , Arai Yoshifusa , Takeuchi Seiji 
Published: April 2003

Abstract
Solid state-specific (γ→β→α)photoisomerization of 3-cyanopropyl and 3-(methoxycarbonyl)propyl cobaloxime complexes were found to occur on visible-light irradiation. There exist considerable differences in the reaction rates, which have no relation to the basicity of the axial ligand. In the former series of complexes, the rate constant (k2) for the second step (β→α) is much faster than that (k1) for the first step. However, in the latter series of complexes, the rate constant (k2) for the second step tends to decrease extremely, and thus, k2 become smaller than k1.
Selective Si–Si Bond Cleavage of Decaisopropylbicyclo[2.2.0]hexasilane with Hydrobromic Acid and Hydrochloric Acid
Authors: Meguro Akira , Sakurai Haruaki , Kato Kei , Kyushin Soichiro , Matsumoto Hideyuki 
Published: April 2003

Abstract
In the reactions of decaisopropylbicyclo[2.2.0]hexasilane (1) with hydrobromic acid and hydrochloric acid, the bridgehead Si–Si bond of 1 was selectively cleaved to give 1-halo-1,2,2,3,3,4,5,5,6,6-decaisopropylcyclohexasilanes. The X-ray crystallographic analysis of the products indicates that the cis-addition of the acids to the Si–Si bond is preferable.
A New Screw-Sense Switchable Polysilylene with Quantized and Superposed Helicities
Authors: Fujiki Michiya , Motonaga Masao , Tang Hong-Zhi , Torimitsu Keiichi , Zhang Zhong-Biao , Koe Julian R , Watanabe Junji , Terao Ken , Sato Takahiro , Teramoto Akio 
Published: April 2003

Abstract
A new rod-like polysilylene bearing a β-branched alkyl group, poly[(S)-3,7-dimethyloctyl(2-ethylbutyl)silylene], was found to undergo a thermo-driven, helix–helix transition at −7 °C in isooctane associated with the discontinuous changes in the singlet σ–σ* excitation energy in the silicon backbone in the switching temperature region.
Estimation of the Emission of Volatile Organic Compounds (VOCs) in Tokyo from Their Observed Increments of the Atmospheric Averaged Concentrations above the Background Concentrations
Authors: Miyoshi Takao , Makide Yoshihiro 
Published: April 2003

Abstract
Emissions of 21 VOCs in the Tokyo area were estimated from the increments of the averaged concentrations on weekdays above the background concentrations. Their relative data were converted to actual emissions per capita based on statistical information of several compounds. The correlation with CFC substitutes was indicated to be most useful.
Origin of Microporosity of Ammonium Dodecatungstophosphate Unveiled by Single Crystal Structure Analysis
Authors: Ito Takeru , Hashimoto Masato , Uchida Sayaka , Mizuno Noritaka 
Published: April 2003

Abstract
The single crystals of ammonium dodecatungstophosphate were successfully synthesized and the structure was analyzed. The intrinsic crystal structure (cubic, Pn3- m) had no cavity. It follows that the microporosity observed for the powdery sample originated from narrow spaces surrounded by the fine nanocrystallites.
Selective Synthesis of Methanol from CO + H2 over Pd Sulfide in the Presence of H2S
Authors: Koizumi Naoto , Miyazawa Akihiro , Furukawa Takuro , Yamada Muneyoshi 
Published: April 2003

Abstract
Both bulk and SiO2-supported Pd sulfides were found to show methanol synthesis activity from CO + H2 (syngas). SiO2-supported Pd sulfide yielded 120 g kg-cat−1 h−1 of methanol at 613 K, 5.1 Mpa and 20 m3 (STP) kg-cat−1 h−1. In the presence of H2S 120 ppm in concentration, it preserved 40% of the activity that was obtained under the sulfur-free conditions.
Palladium-Catalyzed Cyclizations of 1,6-Dienes in the Presence of Lewis Acids
Authors: Oh Chang Ho , Kim Jung Duk , Han Je Wook 
Published: April 2003

Abstract
Palladium-catalyzed cyclizations of several 1,6-dienes were accomplished by utilizing a catalytic amount of additives. Use of Lewis acids gave the endocyclic compounds, while use of silver(I) salts gave the exocyclic compounds.
Potentiometric SCN− Selectivity of Polymer Membranes with Fixed Organotin Compounds
Authors: Moriuchi-Kawakami Takayo , Aoto Hiroshi , Fujimori Keiichi , Shibutani Yasuhiko 
Published: April 2003

Abstract
Novel polymer liquid membrane electrodes, in which the organotin compounds were fixed, were obtained by the reaction of PVC (poly(vinyl chloride)) with di-n-butyltin halide hydrides (nBu2SnYH, Y = F, Cl, I, Ome). The improved liquid membrane electrodes displayed good potential stability and non-Hofmeister selectivity patterns. Furthermore, the highest degree of selectivity for the SCN− ion was achieved.
Production of Acetic Acid Directly from Methane and Carbon Dioxide Using Dielectric-Barrier Discharges
Authors: Liu Chang-jun , Li Yang , Zhang Yue-ping , Wang Yu , Zou Jijun , Eliasson Baldur , Xue Bingzhang 
Published: April 2003

Abstract
The atomic economic reaction of acetic acid formation from methane and carbon dioxide via dielectric-barrier discharges at ambient conditions was investigated in this work. A significantly high selectivity of acetic acid (up to 5.3%) has been achieved with high conversions of methane (more than 54.1%) and carbon dioxide (more than 37.4%).
Enantioselective Radical Cross-Coupling Reactions of Silyl Enol Ethers Using Chiral Oxovanadium
Authors: Kurihara Masaaki , Hayashi Taeko , Miyata Naoki 
Published: April 2003

Abstract
Asymmetric induction was observed in radical cross-coupling reactions of silyl enol ethers using chiral oxovanadium generated in situ from 8-phenylmenthol and vanadium oxytrichloride in the presence of MS4A (molecular sieves-4A).
Synthesis and Crystal Structure of a Chloro-Bridged Dinuclear Germanium(IV) Heterocoordinate Complex with 5,14-Dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine
Authors: Shen Xuan , Sakata Kazunori , Hashimoto Mamoru 
Published: April 2003

Abstract
A novel chloro-bridged dinuclear germanium(IV) complex with 5,14-dihydro-6,8,15,17-tetramethyldibenzo[b,i]-[1,4,8,11]tetraazacyclotetradecine has been synthesized and its crystal structure shows an unsymmetrical heterocoordinate dimer which has a five-coordinate square pyramid and a six-coordinate octahedron.
Synthesis of Binuclear Ligands Possessing Two Discrete Multidentate N-Heterocyclic Podand Coordination Sites and Their Bimetallic Nickel(II) Complexes
Authors: Moriuchi Toshiyuki , Nakayama Isao , Nishimura Kouichirou , Nishiyama Masahito , Mochizuki Eiko , Kai Yasushi , Hirao Toshikazu 
Published: April 2003

Abstract
Binuclear ligands possessing two discrete multidentate N-heterocyclic podand coordination sites connected by a flexible propylene spacer and a rigid m-xylene spacer were synthesized. Treatment of the binuclear ligands with Ni(Oac)2 afforded the bimetallic nickel(II) complexes with two discrete nickel centers. The single-crystal X-ray structure determination of the bimetallic nickel(II) complex with a propylene spacer revealed a little distorted square planar geometry at each nickel center.
The First Alkali Metal Selenothioates: Synthesis and Molecular Structure
Authors: Niyomura Osamu , Sakai Kiyotaka , Murai Toshiaki , Kato Shinzi , Yamaguchi Shigehiro , Tamao Kohei 
Published: April 2003

Abstract
The reaction of S-2-(trimethylsilyl)ethyl selenothioates with KF, CsF, and RbF gave the corresponding alkali metal selenothioates in moderate to good yields. The use of 18-crown-6 ether gave the products in higher yields. The molecular structure analyses of some of metal salts were carried out.
Quantitative Evaluation of Lewis Acidity of Organotin Compounds and the Catalytic Reactivity in Electron Transfer
Authors: Ohkubo Kei , Suenobu Tomoyoshi , Imahori Hiroshi , Orita Akihiro , Otera Junzo , Fukuzumi Shunichi 
Published: April 2003

Abstract
The g-values of ESR spectra of superoxide (O2•−) complexes with various organotin compounds acting as Lewis acids were determined in acetonitrile at 143 K. The binding energies (ΔE) in the complexes between organotins and O2•− have been evaluated from deviation of the gzz-values from the free spin value. The ΔE values are well correlated with the catalytic reactivity of organotins as well as a series of metal ions acting as Lewis acids to promote electron transfer from cobalt(II) tetraphenylporphyrin to O2, which would not occur in the absence of Lewis acids under otherwise the same experimental conditions.
Lewis Acid Mediated Intermolecular Vinylsilylation of Alkynes
Authors: Asao Naoki , Nabatame Kazuyuki , Yamamoto Yoshinori 
Published: April 2003

Abstract
Intermolecular vinylsilylation of the alkynes 1b–c, having an alkoxy group at the homopropargylic position, with the vinylsilane 2 proceeded in the presence of AlBr3 to give the corresponding dienylsilanes 3b–c in moderate to good yields. In contrast, no product was obtained in the reaction of 1-octyne. The AlBr3 mediated vinylsilylation of the phenylacetylene 9c, bearing methoxy group at the ortho position, also proceeded in good yield.
Regioselective Ring Opening of 1-Methyl-1-(1-naphthyl)-2,3-benzosilacyclobut-2-ene by Carbanion and Silyl Anion
Authors: Uenishi Kazuya , Imae Ichiro , Shirakawa Eiji , Kawakami Yusuke 
Published: April 2003

Abstract
Ring opening of 1-methyl-1-(1-naphthyl)-2,3-benzosilacyclobut-2-ene by carbanion and silyl anion was found to proceed regioselectively.
A Novel Photochromic Amorphous Molecular Material Based on Bisthienylethene with a Spiro-linker
Authors: Tian He , Chen Bingzhi , Liu Pei-Hua 
Published: April 2003

Abstract
A novel photochromic amorphous molecule (Spiro-BTE) based on bisthienylethene with a spirobifluorene linker has been synthesized. The relative high photochromic quantum yields were obtained for the Spiro-BTE and the switching stability was observed for more than 200 photochromic cycles. The introduction of the spiro center for photochromic molecules provides a new guideline for the exploring new amorphous photochromic materials with high Tg, good photostability.
Organic aerosols in the air of Milan, Italy. The IIA‐CNR measurement campaign of 2000–2001
Authors: Cecinato Angelo , Scianò Maria Concetta Tomasi , di Menno di Bucchianico Alessandro 
Published: April 2003

AbstractInhalable aerosols collected in downtown Milan during a whole‐year field campaign (from November 2000 to October 2001) were investigated to determine amounts of n‐alkanes, polynuclear aromatic hydrocarbons (PAH), including benzo[a]pyrene (BaP), nitrated PAH (NPAH), and monocarboxylic n‐alkanoic acids. Combustion processes including vehicle emission were confirmed as the most important sources affecting air quality, whereas release of organic material from biota contributed a few percent. The occurrence of in‐situ reactions in the atmosphere promoted by oxidants modified, to some extent, the composition of both PAH and NPAH fractions, by reducing the amount of BaP present in the aerosols and increasing that of NPAH.
Analysis by liquid chromatography‐tandem mass spectrometry of biophenolic compounds in olives and vegetation waters, Part I
Authors: Bianco Armandodoriano , Buiarelli Francesca , Cartoni Giampaolo , Coccioli Franco , Jasionowska Renata , Margherita Pamela 
Published: April 2003

AbstractBiophenolic compounds constitute a complex mixture in olives and derived products. In this work, ion‐spray tandem mass spectrometry coupled with liquid chromatography is applied to the identification and quantification of biophenols present in complex matrices such as olives and vegetation waters. The extraction and purification method for the biophenol present in both the matrices is reported. Using this approach the main biophenols found, in three different variety of olives, were: tyrosol, hydroxytyrosol, oleoside methyl ester, oleoside dimethyl ester, and oleuropein. In vegetation water the biophenols are present in lower amounts than in olives.
Analysis by liquid chromatography‐tandem mass spectrometry of biophenolic compounds in virgin olive oil, Part II
Authors: Bianco Armandodoriano , Buiarelli Francesca , Cartoni Giampaolo , Coccioli Franco , Jasionowska Renata , Margherita Pamela 
Published: April 2003

AbstractIn this study the qualitative and quantitative content of the biophenolics in virgin olive oils is evaluated by liquid chromatography‐tandem mass spectrometry. The extraction and purification method for these compounds from virgin oils was optimised. After liquid‐liquid and solid‐phase extraction the separation of 35 of these compounds was achieved on reversed phase in gradient mode. The detection was preliminarily by UV and fluorescence, but then the final choice was ion‐spray tandem mass spectrometry in multiple reaction monitoring mode in negative ionization, acquiring two diagnostic product ions from the chosen precursor [M—H]–. Using this last approach we obtained the best sensitivity, selectivity, and specificity. The recovery of the method ranged from 70–90% and detection limits were less than 1 ng for all the analyzed compounds.
Capillary Zone Electrophoresis of some organic acids in milk whey
Authors: Buiarelli Francesca , Cartoni Giampaolo , Coccioli Franco , Jasionowska Renata 
Published: April 2003

AbstractThis paper describes a method for analysing some acids of milk whey by Capillary Zone Electrophoresis. After eliminating the whey proteins by ultrafiltration, the whey underwent electrophoretic separation in the presence of anodic electroosmotic flow. The following analytes were detected: citric, orotic, uric, and hippuric acids. A procedure is described for sample preparation and the operating conditions for electrophoretic capillary separation established. Finally, orotic acid is quantitatively determined.
CO/Alkene Copolymers as a Promising Class of Biocompatible Materials, 2. Bone Growth Directed Performance of Bone Marrow Cell Spreading
Authors: Röhlke W. , Fuhrmann R. , Franke R.‐P. , Mücke A. , Voegele J. , Rieger B. 
Published: April 2003

AbstractThe influence of polymer polarity of three different CO/alkene copolymers on the production of bone materials by human bone marrow cells was demonstrated. The effects were measured by a specific immunohistochemical glycoprotein (osteonectin, osteopontin) test. Von Kossa staining, as an integral indicator for the formation of hard tissue on the biomaterial surfaces, visualized the obtained findings. The results clearly demonstrated an increase in mineralization activities with decreasing polarity of the tested polymers.Von Kossa staining of octadecene‐propene‐carbonmonoxide matrix (OdPCO).magnified imageVon Kossa staining of octadecene‐propene‐carbonmonoxide matrix (OdPCO).
A novel approach to spot detection for two‐dimensional gel electrophoresis images using pixel value collection
Authors: Cutler Paul , Heald Geoffrey , White Ian R. , Ruan Jason 
Published: April 2003

AbstractSeparation of complex mixtures of proteins by two‐dimensional gel electrophoresis (2‐DE) is a fundamental component of current proteomic technology. Quantitative analysis of the images generated by digitization of such gels is critical for the identification of alterations in protein expression within a given biological system. Despite the availability of several commercially available software packages designed for this purpose, image analysis is extremely resource intensive, subjective and remains a major bottleneck. In addition to reducing throughput, the requirement for manual intervention results in the introduction of operator subjectivity, which can limit the statistical significance of the numerical data generated. A key requirement of image analysis is the accurate definition of protein spot boundaries using a suitable method of image segmentation. We describe a method of spot detection applicable to 2‐DE image files using a segmentation method involving pixel value collection via serial analysis of the image through its range of density levels. This algorithm is reproducible, sensitive, accurate and primarily designed to be automatic, removing operator subjectivity. Furthermore, it is believed that this method may offer the potential for improved spot detection over currently available software.
Proteomic analysis of eIF‐5A in lung adenocarcinomas
Authors: Chen Guoan , Gharib Tarek G. , Thomas Dafydd G. , Huang Chiang‐Ching , Misek David E. , Kuick Rork D. , Giordano Thomas J. , Iannettoni Mark D. , Orringer Mark B. , Hanash Samir M. , Beer David G. 
Published: April 2003

AbstractWe examined the eIF‐5A protein expression in 93 lung adenocarcinomas and 10 uninvolved lung samples using quantitative two‐dimensional polyacrylamide gel electrophoresis (2‐D PAGE) analysis with identification by mass spectrometry and 2‐D Western blots. The same tissue samples were examined for the eIF‐5A mRNA expression using oligonucleotide microarrays, and the cellular localization of the eIF‐5A protein was examined using immunohistochemical analysis on tissue arrays. Higher eIF‐5A protein expression was present in tumors showing poor differentiation, 12/13th codon K‐ras mutations, p53 nuclear accumulation, and tumors with positive lymphocytic response. The eIF‐5A mRNA was also significantly increased in lung adenocarcinomas compared to normal lung, but the eIF‐5A protein expression was not correlated to its mRNA levels indicating that the increase in the eIF‐5A protein expression in lung tumors is post‐transcriptionally/translationally/post‐translationally regulated. Patients having a higher eIF‐5A protein expression showed a relatively poorer survival suggesting the use of eIF‐5A as prognostic marker in lung adenocarcinoma. Moreover, the investigation on agents that inhibit eIF‐5A function is encouraged.