bluuebunny/crossref_metadata_2025 huggingface dataset:
Homogeneous N,O-Acylation of Chitosan in Dimethyl Sulfoxide with Cyclic Acid Anhydrides
Authors: Sashiwa Hitoshi , Shigemasa Yoshihiro , Roy René
Published: May 2005

By using soluble chitosan (1R)-(−)-10-camphorsulfonate salt (chitosan-CSA), N,O-acylated chitosans were prepared in dimethyl sulfoxide (DMSO) with cyclic acid anhydride under homogeneous conditions.
Redox Behavior of Human Serum Albumin–Heme Hybrid on Graphite Electrode Modified with Didodecyldimethylammonium Bromide
Authors: Wu Yuping , Komatsu Teruyuki , Tsuchida Eishun
Published: May 2005

The redox behavior of a synthetic hemoprotein, the recombinant human serum albumin (rHSA), incorporating a tetraphenylporphinatoiron derivative (FeP) [rHSA-FeP] was first evaluated using a graphite electrode modified with didodecyldimethylammonium bromide as a promoter. Compared to that of the naked FeP, the redox potential of the Fe(III)/Fe(II) couple in rHSA-FeP shifts in the positive direction, indicating that the central ferrous ion of FeP becomes more difficult to be oxidized by incorporation into the albumin structure.
Indium-Mediated Facile Dehydration and Beckmann Rearrangement of Oximes
Authors: Barman Dhiren C , Thakur Ashim J , Prajapati Dipak , Sandhu Jagir S
Published: May 2005

Indium chloride has been developed as an efficient reagent for the conversion of aldoximes to nitriles and the Beckmann rearrangement of ketoximes to anilides.
Synthesis of Manganite Perovskites by Reverse Homogeneous Precipitation Method in the Presence of Alkylammonium Cations
Authors: Teraoka Yasutake , Nanri Shinichi , Moriguchi Isamu , Kagawa Shuichi , Shimanoe Kengo , Yamazoe Noboru
Published: May 2005

A single-phase LaMnO3+δ perovskite with high surface area could be synthesized after air-calcining the hydroxide precursor at 650 °C and above. The precursor was easily obtained by dropping a mixed aqueous solution of La and Mn nitrates into highly basic aq. NH3 with and without the presence of N(CH3)4Br. The addition of N(CH3)4Br was effective in increasing the specific surface area of the products as well as in stabilizing the colloidal solution of the hydroxide precursor.
Photocatalytic Water Splitting into H2 and O2 over K2LnTa5O15 Powder
Authors: Kudo Akihiko , Okutomi Hiroaki , Kato Hideki
Published: May 2005

K2LnTa5O15 (Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, and Tm) loaded with NiO co-catalysts showed photocatalytic activities for water splitting into H2 and O2 in stoichiometric amounts under UV light irradiation (hν > 3.9-4.1 eV). The photocatalytic activities strongly depended on the lanthanide ions. Among them, K2PrTa5O15 and K2SmTa5O15 showed relatively high activities.
Artificial Urushi: Design, Synthesis, and Enzymatic Curing of New Urushiol Analogues
Authors: Kobayashi Shiro , Ikeda Ryohei , Oyabu Hiroshi , Tanaka Hozumi , Uyama Hiroshi
Published: May 2005

“Artificial urushi” was prepared by laccase-catalyzed curing of new urushiol analogues. The curing of the catechol derivative having a linolenoyl group proceeded in the presence of acetone powder, yielding the crosslinked film (artificial urushi) with high hardness and gloss surface, which are comparable with those of natural urushi coating.
Stereoselective Formation of Cyclopropylsilane through Intramolecular Rearrangement of [(Allyloxy)dimesitylsilyl]lithiums
Authors: Kawachi Atsushi , Maeda Hirofumi , Tamao Kohei
Published: May 2005

A [(sec-allyloxy)dimesitylsilyl]stannane bearing a phenyl group on the olefin part reacts with n-BuLi in THF to give a cyclopropylsilane as a single diastereomer, in contrast to the [2,3]-sila-Wittig rearrangement affording an allylsilane, previously observed for a substrate bearing an alkyl group on the olefin part. The striking substituent effect is revealed by ab initio calculations in terms of the regioselectivity in the reaction of silyllithiums with an olefin.
Removal of Palladium(II) from Aqueous and Organic Solutions by Polystyrene-bound Trimercaptotriazine
Authors: Ishihara Kazuaki , Nakayama Masaya , Kurihara Hideki , Itoh Akihide , Haraguchi Hiroki
Published: May 2005

Polystyrene-bound 2,4,6-trimercapto-s-triazine was prepared from 2,4,6-trimercapto-s-triazine (TMT) and Merrifield resin in a single step. Treatment with polymer-bound TMT was highly effective for reducing the concentration of residual Pd(II) in aqueous and organic solutions.
Electronic Structure and Chemical Bonding of Li and Protons in Spinel Type Manganese Oxides by Cluster Calculation
Authors: Kim Yang-Soo , Kanoh Hirofumi , Chitrakar Ramesh , Hirotsu Takahiro , Ooi Kenta
Published: May 2005

A study of the electronic structure and chemical bonding of the Li and proton exchange in spinel-type manganese oxides is performed by a first-principles molecular-orbital method using model clusters composing of 57 atoms. The discrete-variational (DV)-Xα method was employed and Mulliken’s population analyses were thoroughly conducted. We found that Li and proton in manganese oxides is highly ionized. Strong covalent interactions between Mn and O can be noted.
Ring Contraction of 1,2-Digermacyclohexa-3,5-dienes Initiated by Electron Transfer Reactions with TCNE
Authors: Mochida Kunio , Shimizu Hiromi , Nanjo Masato
Published: May 2005

The thermal reaction of 1,2-digermacyclohexa-3,5-dienes with tetracyanoethylene (TCNE) gave 1-germacyclopenta-2,4-diene as a germylene extrusion compound through a charge-transfer complex. The 1-germacyclopenta-2,4-diene was trapped with TCNE to give 5,5,6,6-tetracyano-7-germanorbornene.
Stereoselective (2π + 2π) Photocycloaddition of Arylalkenes to Chrysene
Authors: Maeda Hajime , Waseda Shigeyuki , Mizuno Kazuhiko
Published: May 2005

Photocycloaddition of electron-deficient arylalkenes to chrysene stereoselectively occurred at 5,6-position of chrysene ring to give two (2π + 2π) photocycloadducts through sandwich-type singlet exciplexes. Photocycloreversion took place via the excited singlet states of the photocycloadducts.
Infrared Photodissociation Spectra of Halomethane Halide Cluster Anions and Their Solvation Structures
Authors: Ichihashi Masahiko , Sadanaga Yasuhiro , Lisy James M , Kondow Tamotsu
Published: May 2005

Solvation structures of X−(CH3X)n (X = Cl and Br) were studied by use of infrared photodissociation spectroscopy (925–1090 cm−1) together with mass spectroscopy. The cluster anion, X−(CH3X)n (n ≥ 13) was found to have an absorption peak at a vibrational wavenumber, which is comparable to that of the X–C–H bending mode of a free CH3X molecule. On the other hand, X−(CH3X)12 did not exhibit any detectable absorption at the wavenumbers studied. It was concluded that the first solvation shell of the cluster anion is completed at n = 12 (icosahedral structure), and that with a sub-shell is completed at n = 18 (capped icosahedral structure).
Preparation of a New Class of Inner Salts by Formal Addition of Tosyl Nitrene to the Sulfur Atom of Inner Salts, α-Carbeniodithiocarboxylates
Authors: Nakayama Juzo , Zhao Liting , Otani Takashi , Sugihara Yoshiaki , Ishii Akihiko
Published: May 2005

2,2-Bis(diethylamino)-2-ethylium-1-dithiocarboxylate (1a) was S-iminated by [N-(p-tolylsulfonyl)imino]phenyliodinane to provide a novel inner salt (4a) that formally possesses a thione-S-imide structure (>C=S=NR) as one of the canonical structures.
A New and One-Pot Synthesis of α,β-Unsaturated Ketones by Dehydrogenation of Various Ketones with N-tert-Butyl Phenylsulfinimidoyl Chloride
Authors: Mukaiyama Teruaki , Matsuo Jun-ichi , Kitagawa Hideo
Published: May 2005

α,β-Unsaturated ketones were synthesized by one-pot procedure from various ketones in good to excellent yields on treatment of their lithium enolates with N-tert-butyl phenylsulfinimidoyl chloride (1) under mild conditions.
Synthesis and Characterization of Amorphous Phosphorus Nitride
Authors: Meng Zhaoyu , Peng Yiya , Yang Zhiping , Qian Yitai
Published: May 2005

Amorphous phosphorus nitride (P3N5) has been synthesized from the reaction of PCl5 and NaN3 in an autoclave at 190–300 °C. XPS, IR and TEM revealed that the product was amorphous P3N5 with flake-like morphology. The influences of experimental conditions were discussed.
IR Evidence for the Generation of (C5H5)Mn(CO)2(N2O) in Near-Critical N2O at Room Temperature and in Polyethylene Matrices at Low Temperature
Authors: Molvinger Karine , Childs Gavin I , Jobling Margaret , Roper Mark , George Michael W , Poliakoff Martyn
Published: May 2005

UV photolysis of CpMn(CO)3 (Cp = C5H5) in near critical liquid N2O at room temperature in both static and flow reactors leads to the formation of CpMn(CO)2(N2O) identified via ν(C–O) and ν(N2O) IR bands, the latter being recorded in low temperature polyethylene (PE) experiments. CpMn(CO)2(N2O) has a lifetime of ca. 5 min at room temperature in near-critical N2O and appears to have two decay pathways one of which leads to CpMn(CO)2(N2), possibly via O-transfer.
Mordenite-Supported Noble Metal Catalysts for Selective Oxidation of Carbon Monoxide in a Reformed Gas
Authors: Igarashi Hiroshi , Uchida Hiroyuki , Watanabe Masahiro
Published: May 2005

Selective oxidation of carbon monoxide in high excess of H2 was examined on noble metal catalysts (Pt, Ru, Pd, Co, and Pt-Ru) supported on mordenite. Pt-Ru/mordenite exhibited fairly high selectivity over a wide flow rate condition even at 150 °C. Thus, it seems to be a promising catalyst for polymer electrolyte fuel cells operated with reformed gas.
Remarkable Temperature Dependence of Two-Photon Absorption Spectrum of Poly(dihexylsilylene) in Solution
Authors: Miyazawa Takashi , Saeki Titao , Liu Chengyou , Kira Mitsuo
Published: May 2005

The nonresonant two-photon absorption spectrum of poly(dihexylsilylene) (1) in 3-methylpentane solution showed an abrupt thermochromism with a similar transition temperature to the one-photon absorption spectrum of 1. The parallel temperature dependence between the one-photon and two-photon absorption spectra suggests that the two-photon excited state involves an important contribution of the σ–σ* excited electronic configurations.
Suppression of Methanol Crossover in Pt-Dispersed Polymer Electrolyte Membrane for Direct Methanol Fuel Cells
Authors: Uchida Hiroyuki , Mizuno Yohsuke , Watanabe Masahiro
Published: May 2005

Suppression of methanol crossover in polymer electrolyte membranes is a key technology for direct methanol fuel cells (DMFCs). We have prepared a Nafion® 117 wherein platinum nanocrystals are highly dispersed and subsequently used it in a DMFC. This is expected to suppress the short-circuit reaction by oxidizing methanol at the Pt catalysts. Indeed, this is observed by the appreciable increase in the cathode potential, resulting from the reduced amount of methanol reaching the cathode.
Post-Metallocenes: New Bis(pyrrolyl-2-aldiminato) Titanium Complexes for Ethylene Polymerization
Authors: Yoshida Yasunori , Matsui Shigekazu , Takagi Yukihiro , Mitani Makoto , Nitabaru Masatoshi , Nakano Takashi , Tanaka Hidetsugu , Fujita Terunori
Published: May 2005

Two new bis(pyrrolyl-2-aldiminato) titanium complexes were synthesized and their structures determined by X-ray analyses. These complexes displayed high ethylene polymerization activity using MAO or Ph3C+B−(C6F5)4/iBu3Al as a cocatalyst. One of the complexes exhibited very high ethylene polymerization activity (14100 kg-polymer·mol-Ti−1·h−1) with very high molecular weight (Mv: 260.1 × 104) using MAO as a cocatalyst.
1,2-Cis Selective Glycosylation with Glycosyl Fluoride by Using a Catalytic Amount of Trifluoromethanesulfonic Acid (TfOH) in the Coexistence of Molecular Sieve 5Å (MS5Å)
Authors: Jona Hideki , Takeuchi Kazuya , Mukaiyama Teruaki
Published: May 2005

Stereoselective glycosylation of several glycosyl acceptors with 2,3,4,6-tetra-O-benzyl-β-d-glucopyranosyl fluoride was successfully carried out in diethyl ether by using a catalytic amount of trifluoromethanesulfonic acid (TfOH) in the coexistence of molecular sieve 5Å (MS5Å) to afford predominantly the corresponding α-linked disaccharides in high yields, which was applied to one-pot sequential syntheses of trisaccharides.
Photoreaction of Methyl (p-Nitrophenyl)diazoacetate in the Presence of an Electron-Donating Amine: Evidence for Intermediacy of the Carbene Radical Anion
Authors: Mizushima Tadashi , Ikeda Shingo , Murata Shigeru , Ishii Kunihiko , Hamaguchi Hiro-o
Published: May 2005

The product distribution in the photolysis of methyl (p-nitrophenyl)diazoacetate in MeCN–MeOH (9:1) was dramatically changed by the addition of an electron-donating amine, where the formation of the products derived from the carbene was quenched completely. On the basis of the direct observation of transient species and the dependence of the products on amine concentration, the reaction scheme involving a single electron transfer to afford the carbene radical anion is proposed.
Submicroscopic Morphological Changes of Laser Induced Surface Structure of Collagen, Tendon, and Gelatin Films
Authors: Sugiura Masaru , Tsunoda Katsunori , Yajima Hirofumi , Ishii Tadahiro , Ito Hiroshi , Nagai Yutaka
Published: May 2005

The formation of nap-type or wall-type structures on laser irradiated collagen related biopolymers films is reported. An atomic force microscope (AFM) allows a highly sensitive surface characterization of the same area of the irradiated sample between subsequent laser pulses. A change in surface topography was found to be dependent on the fluence and number of applied pulses. A successive measurement technique of AFM gave significant information on the mechanism of surface structure formation.
A New Reagent to Evaluate Optical Purity of Organic Amines by FAB Mass Spectrometry
Authors: Shizuma Motohiro , Imamura Hiroyuki , Takai Yoshio , Yamada Hitoshi , Takeda Tokuji , Takahashi Shigetoshi , Sawada Masami
Published: May 2005

Optical purity (enantiomeric excess: ee) of organic amine salts such as 1-(1-naphthyl)ethylamine hydrochloride was determined by FAB mass spectrometry using a deuterium-labeled/unlabeled enantiomer pair of a newly synthesized saccharide derivative (Dd-Gal2deg/Ll-Gal2deg-d24), podands.
Separation of Solid Polymers by Magneto-Archimedes Levitation
Authors: Kimura Tsunehisa , Mamada Shogo , Yamato Masafumi
Published: May 2005

Solid polymers, including polystyrene, poly(ethylene terephthalate), poly(methyl methacrylate), and so forth, suspended in a paramagnetic aqueous solution were levitated in different vertical positions under a magnetic field gradient. This phenomenon will be used for separating solid polymers.
Synthesis of Hole-Transporting Hydrazone Dendrimers
Authors: Nam Haehyun , Kang Dae Ho , Kim Jai Kyeong , Park Soo Young
Published: May 2005

Hole-transporting aromatic hydrazone dendrimers were synthesized by convergent method. Structures of dendrimers were characterized by NMR, IR, GC/MS (FAB+), and elemental analysis.
Efficient Method to Analyze NMR Spectra of Solutes in Liquid Crystals: The Use of Genetic Algorithm and Integral Curves
Authors: Takeuchi Hiroshi , Inoue Kaori , Ando Yuta , Konaka Shigehiro
Published: May 2005

A new approach is proposed for the analysis of complex NMR spectra of solutes in liquid crystals. In the analysis, NMR spectra are transformed to integral curves and spectral parameters are refined by means of genetic algorithm. The 1H-NMR spectra of ethanol, trans-azobenzene and tolan in ZLI 1132 were successfully analyzed by this method.
Novel Layered Silica/Organic Polymer Hybrid Films with the Interface Linked by Si–C Bonds
Authors: Shimojima Atsushi , Kuroda Kazuyuki
Published: May 2005

Inorganic-organic hybrids films composed of alternating layers of siloxane network and organic polymer assemblies linked by Si–C bonds have been prepared via co-hydrolysis and polycondensation of alkenyltriethoxysilane-tetraethoxysilane mixtures followed by organic polymerization, providing a new methodology for the design and construction of inorganic-organic nanostructured materials.
Preparation of Proton Conductive Phosphosilicate Gels Derived from 2-(Diethoxyphosphoryl)ethyltriethoxysilane
Authors: Kanzaki Takao , Matsuda Atsunori , Kotani Yoshinori , Tatsumisago Masahiro , Minami Tsutomu
Published: May 2005

The phosphosilicate gels derived from the mixture of 2-(diethoxyphosphoryl)ethyltriethoxysilane (DPTS) and tetraethoxysilane (TEOS) showed a high proton conductivity after a heat treatment at 450 °C. The high conductivity was brought by the generation of large amounts of isolated orthophosphoric acid in the gels due to the thermal decomposition of DPTS.
Synthesis and Charge Transfer Complexation of Chiral Polynitrohelicenes
Authors: Okubo Hitoshi , Nakano Daisuke , Yamaguchi Masahiko , Kabuto Chizuko
Published: May 2005

1,12-Dimethylbenzo[c]phenanthrene-5,8-dinitrile is nitrated at symmetrical positions giving 2,11-dinitro-, 4,9-dinitro, and 2,4,9,11-tetranitrohelicenes depending on the reaction conditions. The electron-deficient helicenes form charge-transfer (CT) complexes with pyrene in the solution as well as in the solid state. Crystal of the CT complex obtained from either (P)- or (±)-tetranitrohelicene possesses columnar structure but with different helicity, diameter, and pitch.
Copper-Catalyzed Oxidative Coupling of 2,4,6-Trimethylphenol with Oxygen
Authors: Oyaizu Kenichi , Saito Kei , Tsuchida Eishun
Published: May 2005

2,4,6-Trimethylphenol was oxidized with oxygen in the presence of (1,4,7-tribenzyl-1,4,7-triazacyclononane)copper(II) chloride as a catalyst to produce exclusively a coupled product stilbenequinone, without the formation of oxygenated products.
A Unique Concentration Dependence of NMR Longitudinal Relaxation Time of Water in Supercritical Carbon Dioxide
Authors: Kanakubo Mitsuhiro , Liew Chee C , Aizawa Takafumi , Kawakami Takanori , Sato Osamu , Ikushima Yutaka , Hatakeda Kiyotaka , Saito Norio
Published: May 2005

1H NMR longitudinal relaxation times (T1obs) of water in supercritical carbon dioxide were precisely measured as a function of water concentration (c) at 313.3 K and at 10 and 20 Mpa. 1/T1obs linearly decreased with increasing c up to ∼12 mol m−3, and then was less sensitive to c. Because the spin-rotation interaction is the predominant mechanism in T1obs, the concentration dependence reflects a change in the hydrogen bonding structure between water molecules in the solutions.
Crystallization of Calcium Phosphate Templated by α-Amino Acids Depending on Their Composition, Chain Length, and Enantiomerism
Authors: Kijima Tsuyoshi , Yamaguchi Keisuke , Miyata Akira , Yada Mitsunori , Machida Masato , Tanaka Junzo
Published: May 2005

α-Amino acids showed a characteristic templating effect on the crystallization of calcium phosphate at pH 7.0. Neutral but polar or basic group bearing amino acids yielded hydroxyapatite predominantly, whereas n-alkyl amino acids produced octacalcium phosphate (OCP) leading to an increase in crystallinity, expansion in cell volume and/or interlayer contraction depending on their chain length and enantiomerism. Aspartic acid, a short chain acidic amino acid, formed an amino acid complexed OCP with a significant increase of its crystallinity in the order of d ≈ l < Dl, in contrast to the partial formation of a similar composite for glutamic acid.
Electrochemiluminescence of Luminol Generated at Self-Assembled Monolayer of Ferrocenylalkanethiol on Gold Electrode
Authors: Sato Yukari , Yabuki Soichi , Mizutani Fumio
Published: May 2005

Self-assembled monolayer of ferrocenylundecanethiol on gold electrode catalyzed electro-oxidative chemiluminescence from a luminol/hydrogen peroxide system.
Synthesis and Photochromic Property of cis-Azobenzene Complex with a Binuclear η6-Areneruthenium(II) Unit
Authors: Miyaki Yoshiharu , Onishi Takafumi , Kurosawa Hideo
Published: May 2005

A cis-azobenzene complex with a binuclear ruthenium(II) unit bridged by alkoxo ligands which are tethered to η6-arene donors (4) was synthesized from corresponding binuclear acetonitrile complex (3) and trans-azobenzene irradiated by UV light (300 nm < λ < 400 nm). On irradiation with visible light (λ > 510 nm) in acetonitrile, 4 mostly dissociated to trans-azobenzene and 3 with the photostationary ratio 3/4 = 92/8.
Photochromism of Diarylethenes Having Isopropyl Groups at the Reactive Carbons. Thermal Cycloreversion of the Closed-Ring Isomers
Authors: Kobatake Seiya , Uchida Kingo , Tsuchida Eriko , Irie Masahiro
Published: May 2005

Diarylperfluorocyclopentenes having 2-isopropyl-5-phenylthiophene and 2-isopropyl-1-benzothiophene aryl groups underwent thermally reversible photochromism in solution. The photogenerated colored closed-ring isomers returned to the initial colorless open-ring isomers above 60 °C. The activation energies of the thermal cycloreversion were estimated to be 118 and 132 kJ/mol for the thiophene and benzothiophene derivatives, respectively.
Synthesis and X-ray Analysis of Mn–Mo Mixed Metal Oxide Cluster with Cubic Framework
Authors: Nishikawa Koji , Kinoshita Isamu , Nishioka Takanori , Isobe Kiyoshi
Published: May 2005

A reaction of the dinuclear oxometalate [Bun4N]2[Mo2O7] and (tacn)MnCl3 (tacn = 1,4,7-triazacyclononane) in water afforded a new cubic type Mn–Mo mixed metal oxide cluster of [{(tacn)Mn}2Mo4O16]·4H2O which has a moderate bleaching ability towards pinacyanol chloride dye.
Hydrogen Transfer in a Hydrogen-Bonded 1:2 Complex of Chloranilic Acid with 1,2-Diazine Studied by 35Cl NQR
Authors: Nihei Taka-aki , Ishimaru Shin’ichi , Ishida Hiroyuki , Ishihara Hideta , Ikeda Ryuichi
Published: May 2005

35Cl NQR frequencies and spin–lattice relaxation time, and 1H NMR spin–lattice relaxation time were measured on (chloranilic acid)-(1,2-diazine) 1:2 molecular complex to detect H-transfer motions in the H-bonded three molecular system. Only a single H-jump mode was observed by 1H NMR, whereas three kinds of H-transfer modes were obtained in 35Cl NQR in good agreement with the prediction.
The Chemistry of Alkylstrontium Halide Analogues: Barbier-type Alkylation of Imines with Alkyl Halides
Authors: Miyoshi Norikazu , Ikehara Daitetsu , Kohno Tadashi , Matsui Aki , Wada Makoto
Published: May 2005

The chemistry of alkylstrontium halide analogues was examined. In the presence of metallic strontium, the Barbier-type alkylation of imines with alkyl iodides proceeded smoothly at room temperature under an argon atmosphere to afford the corresponding alkylated amines in good yields.
Greatly Enhanced Photovoltaic Performance by Introducing Hydroxyl or Benzene Ring into D–π–A Dye Framework: Dye Sensitized Solar Cells Based on Rhodanine Dyes
Authors: Chen Yousheng , Li Chao , Zeng Zhanghua , Wang Weibo , Wang Xuesong , Zhang Baowen
Published: May 2005

The introduction of hydroxyl group into aniline moiety (electron donor, D) or benzene ring into the conjugation chain (π bridge) of D–π–A dye framework with rhodanine-3-acetic acid as electron acceptor (A) improved remarkably the monochromatic incident photon-to-current conversion efficiencies (IPCEs) and overall power conversion efficiencies (η), fully demonstrating the potential of molecular design in developing efficient D–π–A dyes for dye-sensitized solar cell applications.
A Remarkable CoIIIMnIIAgI Heterometallic Aggregate with l-Cysteinate That Accommodates Chiral Cobalt(III) Octahedra in a 1D Channel
Authors: Aridomi Takashi , Hirotsu Masakazu , Yoshimura Takashi , Kawamoto Tatsuya , Konno Takumi
Published: May 2005

Treatment of an aqueous solution of Δl-[Co(l-Hcys-N,S)(en)2](ClO4)2 (l-cys = l-cysteinate) with AgNO3 under a neutral condition, followed by the addition of excess Mn(NO3)2, led to the formation of a CoIIIMnIIAgI coordination polymer, {(Δl)5-[Ag2Mn3(NO3)2(H2O)10{Co(l-cys-N,S)(en)2}5](NO3)6.5(ClO4)4.5}n (1). The crystal structure of 1, which accommodates Δl-[Co(l-cys-N,S)(en)2]+ molecules in a 1D channel, was determined by X-ray crystallography.
Human mitochondrial tRNAMet is exported to the cytoplasm and associates with the Argonaute 2 protein
Authors: MANIATAKI ELISAVET , MOURELATOS ZISSIMOS
Published: May 2005

Argonaute (Ago) proteins are the effector proteins of RNA interference (RNAi) and related silencing mechanisms that are mediated by small RNAs. Ago proteins bind directly to microRNAs (miRNAs) and to short interfering RNAs and are the core protein components of RNA induced silencing complexes (RISCs) and microRNPs (miRNPs). Here we report that an ~70-nt RNA associates specifically with immunopurified Ago2 expressed in human 293 cells. By directional cloning we identified this RNA as the mitochondrial tRNAMet (mt tRNAMet). Various exported (mt) tRNAs were detected in the cytosol of 293 cells, but Ago2 was found selectively bound to (mt) tRNAMet. The association in the cytosol of exported (mt) tRNAMet with Ago2 complements genetic and microscopic data that link mitochondria with RNAi-related components and events.
Characterization of conserved sequence elements in eukaryotic RNase P RNA reveals roles in holoenzyme assembly and tRNA processing
Authors: XIAO SHAOHUA , DAY-STORMS JEREMY J. , SRISAWAT CHATCHAWAN , FIERKE CAROL A. , ENGELKE DAVID R.
Published: May 2005

RNase P is a ubiquitous endoribonuclease responsible for cleavage of the 5′ leader of precursor tRNAs (pre-tRNAs). Although the protein composition of RNase P holoenzymes varies significantly among Bacteria, Archaea, and Eukarya, the holoenzymes have essential RNA subunits with several sequences and structural features that are common to all three kingdoms of life. Additional structural elements of the RNA subunits have been found that are conserved in eukaryotes, but not in bacteria, and might have functions specifically required by the more complex eukaryotic holoenzymes. In this study, we have mutated four eukaryotic-specific conserved regions in Saccharomyces cerevisiae nuclear RNase P RNA and characterized the effects of the mutations on cell growth, enzyme function, and biogenesis of RNase P. RNase P with mutations in each of the four regions tested is sufficiently functional to support life although growth of the resulting yeast strains was compromised to varying extents. Further analysis revealed that mutations in three different regions cause differential defects in holoenzyme assembly, localization, and pre-tRNA processing in vivo and in vitro. These data suggest that most, but not all, eukaryotic-specific conserved regions of RNase P RNA are important for the maturation and function of the holoenzyme.
Inducible Nitric Oxide Synthase Immunoreactivity in the Granulomatous Intestinal Lesions of Naturally Occurring Bovine Johne's Disease
Authors: Hostetter J. , Huffman E. , Byl K. , Steadham E.
Published: May 2005

Inducible nitric oxide synthase (iNOS) is important in the control of a number of intracellular pathogens, including mycobacteria, and is a marker of classic macrophage activation. In human granulomatous diseases such as leprosy, a spectrum of granulomatous lesions is described, ranging from the tuberculoid to lepromatous types. Tuberculoid granulomas are associated with enhanced iNOS production and improved clinical outcomes over the lepromatous types. The aim of this study is to determine whether an association exists between morphology of bovine Johne's disease granulomas and lesion macrophage effector functions. To accomplish this, we retrospectively evaluated 24 cases of bovine Johne's disease. In each case, we recorded the predominant granuloma morphology and evaluated iNOS immunoreactivity and bacterial burden by acid-fast stains and mycobacterial immunolabeling. The results of this study demonstrate that all cases had granulomas with features most similar to the lepromatous type. This morphology correlated with heavy bacterial burdens demonstrated by acid-fast staining and mycobacterial immunoreactivity. None of the cases had high expression of iNOS in mycobacterial-positive granulomas. When iNOS immunoreactivity was identified, it was usually located near the crypts and was distinct from the granulomatous foci.
Mapping PrPSc Propagation in Experimental and Natural Scrapie in Sheep with Different PrP Genotypes
Authors: Ersdal C. , Ulvund M. J. , Espenes A. , Benestad S. L. , Sarradin P. , Landsverk T.
Published: May 2005

Twenty-one orally inoculated and seven naturally infected sheep with scrapie were examined for PrPSc in peripheral tissues and in the central nervous system (CNS), using immunohistochemistry. In the inoculated group, VRQ (valine at codon 136, arginine at codon 154 and glutamine at codon 171)/VRQ sheep generally had a greater accumulation of the pathologic form of prion protein (PrPSc) in peripheral tissues, as compared with VRQ/ARQ (alanine at codon 136, arginine at codon 154, and glutamine at codon 171) animals at corresponding time points after inoculation. PrPSc was not detected in the ileal Peyer's patch, the spleen, the superficial cervical lymph node, and peripheral nervous tissues of several inoculated VRQ/ARQ animals. All inoculated VRQ/VRQ sheep, but only one of eight inoculated VRQ/ARQ animals, were PrPSc-positive in the CNS. Thus, the propagation of PrPSc seemed slower and more limited in VRQ/ARQ animals. Tissue and cellular localization of PrPSc suggested that PrPSc was disseminated through three different routes. PrPSc-positive cells in lymph node sinuses and in lymphatics indicated spreading by lymph. The sequential appearance of PrPSc in the peripheral nervous system and the CNS, with satellite cells as early targets, suggested the periaxonal transportation of PrPSc through supportive cells. Focal areas of vascular amyloid-like PrPSc in the brain of five sheep, suggested the hematogenous dissemination of PrPSc. There was a poor correlation between the amount of PrPSc in the CNS and clinical signs. One subclinically affected sheep showed widespread PrPSc accumulation in the CNS, whereas three sheep had early clinical signs without detectable PrPSc in the CNS. A VV136 (homozygous for valine at codon 136) sheep inoculated with ARQ/ARR (alanine at codon 136, arginine at codon 154, and arginine at codon 171) tissue succumbed to disease, demonstrating successful heterologous transmission. Less susceptible sheep receiving VRQ/VRQ or ARQ/ARR material were PrPSc-negative by immunohistochemistry, enzyme-linked immunosorbent assay, and western blot.
The Avian Major Histocompatibility Complex Influences Bacterial Skeletal Disease in Broiler Breeder Chickens
Authors: Joiner K. S. , Hoerr F. J. , van Santen E. , Ewald S. J.
Published: May 2005

This study evaluated bacterial skeletal disease in conjunction with the major histocompatibility complex (MHC) in a genetically pure line of broiler breeder chickens. Chickens from six broiler breeder flocks were examined for skeletal lesions, bacterial pathogens, and MHC genotype. During a 10-week period, eighty-eight, 9- to 21-week-old lame chickens and 34 normal, age-matched controls were selected. Tenosynovitis, arthritis, and femoral or tibiotarsal (or both) osteomyelitis occurred in 86 of 88 (97.7%) lame chickens. Ninety-five bacterial isolates were obtained from 83 of 88 (94.3%) lame birds and 4 of 34 (11.8%) controls. Staphylococcus spp. was isolated from 72.6% of the skeletal lesions, predominantly Staphylococcus aureus (38.9%). MHC B complex genotypes were determined by hemagglutination for 88 lame birds, 34 controls, and 200 randomly selected birds from each of the six flocks (1,200 total). Combined chi-square analysis revealed that the homozygous MHC genotypes BA4/A4 (x2 = 14.54, P = 0.0063) and BA12/A12 (x2 = 42.77, P = 0.0001) were overrepresented in the sample of symptomatic birds compared with random samples from the same flocks. The homozygous A4 and A12 MHC genotypes influenced flock chi-square values more than the corresponding heterozygotes. An MHC B complex influence on bacterial skeletal disease was apparent in this line of broiler breeders.
Uterine Mast Cells and Immunoglobulin-E Antibody Responses During Clearance of Tritrichomonas foetus
Authors: Corbeil L. B. , Campero C. M. , Rhyan J. C. , Anderson M. L. , Gershwin L. J. , Agnew D. W. , Munson L. , BonDurant R. H.
Published: May 2005

We showed earlier that Tritrichomonas foetus-specific bovine immunoglobulin (Ig)G1 and IgA antibodies in uterine and vaginal secretions are correlated with clearance of this sexually transmitted infection. Eosinophils have been noted in previous studies of bovine trichomoniasis but the role of mast cells and IgE responses have not been reported. The hypothesis that IgE and mast cell degranulation play a role in clearance was tested in 25 virgin heifers inseminated experimentally and infected intravaginally with T. foetus strain D1 at estrus and cultured weekly. Groups were euthanatized at 3, 6, 9, or 12 weeks, when tissues were fixed and secretions were collected for culture and antibody analysis. Immunohistochemistry using a monoclonal antibody to a soluble lipophosphoglycan (LPG)-containing surface antigen (TF1.17) demonstrated antigen uptake by uterine epithelial cells. Lymphoid nodules were detected below antigen-positive epithelium. Little IgG2 antibody was detected but IgG1, IgA, IgM, and IgE T. foetus-specific antibodies increased in uterine secretions at weeks 6 and 9 after infection. This was inversely proportional to subepithelial mast cells numbers and most animals cleared the infection by the sampling time after the lowest mast cell count. Furthermore, soluble antigen was found in uterine epithelium above inductive sites (lymphoid nodules). Cross-linking of IgE on mast cells by antigen and perhaps LPG triggering appears to have resulted in degranulation. Released cytokines may account for production of predominantly Th2 (IgG1 and IgE) and IgA antibody responses, which are related to clearance of the infection.
Usefulness of Thyroid Transcription Factor-1 Immunohistochemical Staining in the Differential Diagnosis of Primary Pulmonary Tumors of Dogs
Authors: Ramos-Vara J. A. , Miller M. A. , Johnson G. C.
Published: May 2005

In a previous study, we characterized the reactivity of monoclonal antibody (MoAb) 8G7G3/1 to thyroid transcription factor-1 (TTF-1) in canine thyroid tumors. In this study, we have examined the reactivity of this antibody in 120 canine pulmonary tumors, including 78 primary epithelial tumors. Tissues had been fixed in formalin and routinely processed for histopathology. Nuclear staining for TTF-1 was detected in 64.2% of primary pulmonary epithelial tumors. The most common TTF-1-reactive tumor types were bronchioloalveolar carcinomas and bronchogenic carcinomas. Staining was diffuse, heterogeneous, or patchy. Nonpulmonary, metastatic epithelial tumors, except two of two thyroid carcinomas, did not react with antibody 8G7G3/1. Mesotheliomas and other mesenchymal tumors were also negative for this marker. A reduction or loss of reactivity was apparent in pulmonary epithelial tumors archived in paraffin blocks for 7-8 years. There was slight reduction in the number of positive cells or the intensity of the reaction in control tissues fixed longer than 1 week. On the basis of our limited studies and the human literature, it appears that MoAb 8G7G3/1 to TTF-1 is a highly specific (with the exception of thyroid tumors) and moderately sensitive marker for canine pulmonary epithelial tumors.
Morphologic Features and Development of Granulomatous Vasculitis in Feline Infectious Peritonitis
Authors: Kipar A. , May H. , Menger S. , Weber M. , Leukert W. , Reinacher M.
Published: May 2005

Feline infectious peritonitis (FIP) is a fatal, Coronavirus (CoV)-induced systemic disease in cats, characterized by granulomas in organs and granulomatous vasculitis. This study describes the morphologic features of granulomatous vasculitis in FIP as well as its development in the course of monocyte-associated feline CoV (FCoV) viremia in five naturally infected Domestic Shorthair cats with FIP. Monocyte-associated FCoV viremia was demonstrated by immunohistology, RNA in situ hybridization, and electron micropscopy. Granulomatous phlebitis at different stages of development was observed. Vasculitic processes ranged from attachment and emigration of FCoV-infected monocytes to vascular/perivascular granulomatous infiltrates with destruction of the vascular basal lamina. Monocytes as well as perivascular macrophages were activated because they were strongly positive for CD18 and expressed cytokines (tumor necrosis factor-α and interleukin-1β) and matrix metalloproteinase-9. In addition, general activation of endothelial cells, represented by major histocompatibility complex II upregulation, was observed in all cases. These results confirm FIP as a monocyte-triggered systemic disease and demonstrate the central role of activated monocytes in FIP vasculitis.
Hepatobiliary Neuroendocrine Carcinoma in Cats: A Clinicopathologic, Immunohistochemical, and Ultrastructural Study of 17 Cases
Authors: Patnaik A. K. , Lieberman P. H. , Erlandson R. A. , Antonescu C.
Published: May 2005

Hepatobiliary neuroendocrine carcinoma was diagnosed in 17 cats in a period of 10 years. Seven tumors were of intrahepatic origin, one of which was a composite containing components of epithelial and neuroendocrine carcinoma. Nine tumors were of extrahepatic origin, and one tumor was located in the gallbladder The cats were adult and geriatric, and the male: female ratio varied according to tumor group. Hepatomegaly, anorexia, weight loss, and vomiting were the most common clinical signs observed in the cats with hepatic neuroendocrine carcinoma. The cats with extrahepatic neuroendocrine carcinoma showed these signs plus icterus (5/9) and high concentrations of hepatic enzymes. Histologically, the hepatic neuroendocrine carcinomas had two patterns, one with acinar structures separated by vascular stroma lined by cuboidal or columnar cells and the other solid with groups of anaplastic cells separated by vascular stroma. The composite tumor consisted of both bile duct carcinoma and neuroendocrine carcinoma. The extrahepatic neuroendocrine carcinomas and the gallbladder neuroendocrine carcinoma were characterized by solid sheets or groups of round to oval cells with vascular or fibrovascular stroma. Immunohistochemical examination of 10 of the neuroendocrine carcinomas revealed that all 10 stained with neuron-specific enolase; one bile duct carcinoma and the gallbladder carcinoma stained with chromogranin; four of five bile duct carcinomas and the gall bladder carcinoma stained with synaptophysin; and one bile duct carcinoma stained with gastrin. one cat with hepatic carcinoma had duodenal ulcer; in this cat, ultrastructural studies showed neurosecretory granules leading to the diagnosis of Zollinger-Ellison syndrome. In four cats in which necropsy was permitted, carcinomatosis (4/4), lymph nodes (4/4), lungs (2/4), and intestines (1/4) were the metastatic sites. Fourteen of the 17 cats were euthanatized during or immediately after surgery.
Correlation of Virus Replication in Tissues with Histologic Lesions in Atlantic Salmon Experimentally Infected with Infectious Salmon Anemia Virus
Authors: Moneke E. , Groman D. B. , Wright G. M. , Stryhn H. , Johnson G. R. , Ikede B. O. , Kibenge F. S. B.
Published: May 2005

We have studied the replication of virus in tissues and development of lesions associated with infectious salmon anemia virus (ISAV) infection in Atlantic salmon using in situ hybridization (ISH) with a riboprobe targeting ISAV RNA segment 7 messenger RNA. Fish were infected with three ISAV isolates (U55751, RPC-01-0593-1, Norway 810/9/99) and then euthanatized sequentially at 3, 6, 10, and 13 days postinoculation (dpi) and thereafter once a week for 8 weeks. Severe histopathologic lesions were observed in tissues from all groups beginning at the onset of mortality. The severe histopathologic lesions correlated with maximum intensity and frequency of ISH signals ( P < 0.001). There was a strong association between the hybridization signals and severity of lesions in the liver, kidney, and heart ( R = 0.81, 0.70, and 0.78, respectively; P < 0.001). The distribution of ISH signals indicated the presence of a viremia because signals were observed predominantly in individual blood cells and endothelial cells, and possibly hematopoietic cells of head kidney, but not in the necrotic hepatocytes and renal epithelium. Of the organs sampled, the heart was the first and last to show ISH signals, possibly because of increased activity of the endocardial endothelial cells and the underlining macrophages, which continuously trap and remove circulating virus, and therefore represents the best tissue sample for screening of suspected infected fish. On the basis of mortality, severity of lesions, and intensity and frequency of ISH signals, ISAV isolate Norway 810/9/99 was the most virulent and U5575-1 the least virulent isolate studied.
Assessment of Cyclooxygenase-2 Expression in Canine Hemangiosarcoma, Histiocytic Sarcoma, and Mast Cell Tumor
Authors: Heller D. A. , Clifford C. A. , Goldschmidt M. H. , Holt D. E. , Manfredi M. J. , Sorenmo K. U.
Published: May 2005

To determine whether cyclooxygenase-2 (COX-2) is expressed in canine hemangiosarcoma (HsA), histiocytic sarcoma (Hs), and grade-II mast cell tumor (MCT), we performed immunohistochemistry using COX-2 antibodies in the aforementioned tumors. Twenty cases of each tumor type were selected initially from the Laboratory of Pathology archives of cases submitted through the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania. Immunohistochemistry was performed, using a polyclonal antiprostaglandin endoperoxide synthase immunoglobulin G COX-2 antibody. Sections from the kidneys of young dogs, in which the macula densa stains positive for COX-2, served as positive controls. Slides were reviewed by a single pathologist (M. H. Goldschmidt) and graded for COX-2 expression according to previously established scales.18 Descriptive data is given for each tumor type. COX-2 expression was identified in 0 of 19 HSA, 1 of 20 HS, and 1 of 17 grade-II MCT. Although COX-2 has been shown to be overexpressed in selected human sarcomas and hematopoeitic tumors, these results indicate that canine HSA, HS, and MCT do not express COX-2 in any appreciable fashion.
Unilateral Limb Enlargement in a Dog with a Malignant Peripheral Nerve Sheath Tumor
Authors: Brower A. , Salamat S. , Crawford J. , Manley P.
Published: May 2005

A 3- to 4-month-old female Golden Retriever dog presented with right hind limb enlargement. Physical examination of the limb and radiographic findings initially included soft tissue swelling with elongation, bowing, and cortical irregularity of the femur and tibia. During a period of approximately 7 months, pathology in the limb progressed to include tarsal laxity, muscle atrophy, avulsion of the gastrocnemius muscle, and luxation of the patella. During surgical intervention to shorten the limb and repair the patellar luxation, a large soft tissue cyst was identified along the caudal aspect of the femur and stifle. The limb was later amputated, and a final diagnosis of malignant peripheral nerve sheath (PNS) tumor of the sciatic nerve and surrounding soft tissues was made. The unilateral limb enlargement in this dog appears to have been because of the development and progression of a malignant PNS tumor. The presentation and associated pathologic changes in the limb are unusual for canine PNS tumor but have similarities with neurofibromatosis in the limbs of humans.
Lipid-rich Carcinoma of the Mammary Gland in a Cat
Authors: Kamstock D. A. , Fredrickson R. , Ehrhart E. J.
Published: May 2005

A 1.5-year-old female, intact, clinically healthy cat presented for a subcutaneous mass of the ventral abdomen. surgical excision and microscopic examination of the mass were performed. Histologically, this was a discrete, unencapsulated, multilobular, expansile mass, which compressed the surrounding normal mammary tissue. Lobules were composed of tubuloacinar structures formed by atypical round to polygonal cells, which contained foamy to microvacuolated cytoplasm and variably sized, intracytoplasmic, distinct vacuoles causing nuclear peripheralization. Neoplastic cells demonstrated intense and diffuse immunoreactivity for cytokeratin and lacked immunoreactivity for vimentin. The vacuolar contents stained positively with oil RedO and negatively with periodic acid-Schiff and Alcian blue stains. Histomorphologic, histochemical, and immunohistochemial analysis support a diagnosis of lipid-rich mammary carcinoma. This is the first report of a cat with a lipid-rich variant of mammary carcinoma.
KIT-positive Gastrointestinal Stromal Tumor in a 22-year-old Male Chimpanzee (Pan troglodites)
Authors: Saturday G. A. , Lasota J. , Frost D. , Brasky K. B. , Hubbard G. , Miettinen M.
Published: May 2005

Gastrointestinal stromal tumors (GIST), KIT-positive and KIT signaling driven or platelet-derived growth factor receptor α (PDGFRA) signaling driven mesenchymal tumors, are poorly known in nonhuman primates. Availability of KIT- and PDGFRA-inhibitor drug imatinib mesylate has greatly raised the interest for these tumors. At necropsy of a 22-year-old male chimpanzee, a round, firm 2-cm intramural tumor was incidentally found in the midbody of the stomach and diagnosed as a GIST. Histologically, the mass was composed of spindle to polygonal epithelioid cells arranged in short to intermediate-length, interlacing streams, bundles, and nodular whorls often separated by hyalinized eosinophilic matrix. The mitotic rate was a maximum 1/50 high-power field. Immunohistochemically, the tumor cells were diffusely positive for KIT and CD34, focally positive for α-smooth muscle actin, and negative for muscle specific actin, desmin, S-100 protein, synaptophy-sin, and glial fibrillary acidic protein. Because the majority of human GISTs have gain-of-function KIT or PDGFRA mutations, genomic sequences of KIT exons 9, 11, 13, and 17 and PDGFRA exons 12 and 18 from this chimpanzee GIST were polymerase chain reaction amplified and sequenced. However, no mutation was identified in the analyzed “mutational hot spots.” This study is the first extensive histomorphologic, immunohistochemical, and molecular genetic analysis of a chimpanzee GIST. More cases of nonhuman primate GISTs should be analyzed to discover the clinicopathologic spectrum of GISTs in these species.
Pathology of Bartonella Endocarditis in Six Dogs
Authors: Pesavento P. A. , Chomel B. B. , Kasten R. W. , McDonald K. A. , Mohr F. C.
Published: May 2005

In a 5-year retrospective study of dogs presenting to the Veterinary Medical Teaching Hospital at the University of California, Davis, there were 31 histologic diagnoses of valvular endocarditis. By polymerase chain reaction (PCR) amplification of embedded valvular tissue, Bartonella organisms were exclusively associated with 6 out of 31 cases (19%). Confirmed Bartonella cases involved the aortic valve alone (five out of six) or in combination with the mitral valve (one of six). Microscopic features of Bartonella endocarditis were compared with valves from non -Bartonella endocarditis and with valvular change unrelated to infectious agents (endocardiosis). Features of Bartonella endocarditis included a combination of fibrosis, mineralization, endothelial proliferation, and neovascularization with variable inflammation. None of these features is specific; however, the combination is distinct both from endocarditis caused by culturable bacteria and from endocardiosis. Ultrastructural analyses revealed both extracellular and intraendothelial bacteria. Clinical history, serology, and PCR are currently necessary to establish an etiologic diagnosis of Bartonella endocarditis.
Combined-type Osteosarcoma in a Rhesus Macaque
Authors: Beam S. L.
Published: May 2005

A femoral mass from a 15-year-old rhesus macaque was evaluated. Grossly, the mass consisted of a large, osteolytic focus in the distal femur, a gelatinous core of neoplastic tissue in the medullary cavity, and an invasive mass-obliterating musculature of the thigh. On histopathologic evaluation, three neoplastic mesenchymal cell populations, osteoblasts, fibroblasts, and primitive mesenchymal cells were identified. The mass was diagnosed as a combined type osteosarcoma. To our knowledge, this is the first osteosarcoma in a rhesus macaque with this subclassification.