bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictors of infusion reactions during infliximab treatment in patients with arthritis
Authors: Kapetanovic Meliha C , Larsson Lotta , Truedsson Lennart , Sturfelt Gunnar , Saxne Tore , Geborek Pierre
Published: July 2006

In the present study we evaluated the impact of baseline antinuclear antibody (ANA) status and use of methotrexate on development of infliximab-related infusion reactions in patients with rheumatoid arthritis (RA) or spondylarthropathies (SpAs), including psoriatic arthritis. All patients with RA (n = 213) or SpA (n = 76) treated with infliximab during the period 1999–2005 at the Department of Rheumatology in Lund, Sweden were included. ANAs were present in 28% and 25% of RA and SpA patients, respectively. Because of differences in baseline characteristics, we used a binary logistic regression model to calculate odds ratios (ORs), adjusting for age, sex and prednisolone dosage. Altogether 21% of patients with RA and 13% of patients with SpA developed infusion reactions (P = 0.126). The OR for development of infusion reactions in RA patients with baseline ANA positivity alone was 2.1. Infliximab without methotrexate and infliximab as monotherapy were associated with ORs of 3.1 and 3.6, respectively. Combining infliximab without methotrexate and ANA positivity yielded an OR for infusion reaction of 4.6. Lower age at disease onset and longer disease duration were associated with infusion reactions (P = 0.012 and P = 0.036, respectively), but age, sex, C-reactive protein, erythrocyte sedimentation rate, Health Assessment Questionnaire and Disease Activity Score-28 at baseline were not. No predictors of infusions reactions were identified in SpA patients. RA patients treated with infliximab without methotrexate, and who are positive at baseline for ANAs are at increased risk for developing infliximab-related infusion reactions.
Twenty-Four Hour Growth Hormone and Leptin Secretion in Active Postpubertal Adolescent Girls: Impact of Fitness, Fatness, and Age at Menarche
Authors: Kasa-Vubu J. Z. , Ye W. , Borer K. T. , Rosenthal A. , Meckmongkol T.
Published: July 2006

Context: GH is strongly related to body composition, physical activity, and pubertal progression. Adolescent girls decrease physical activity during puberty, whereas their weight increases. Because leptin is a good index of energy balance in active young women, we hypothesized that leptin is related to GH secretion in this population while taking into account fitness, fatness, and age at menarche.

Methods: We measured body composition and maximal oxygen consumption (VO2max) in 37 postpubertal adolescent girls aged 16–21 yr. GH was sampled every 10 min and leptin hourly for 24 h. We first analyzed 6-h time blocks by repeated measures for GH and leptin, with body mass index (BMI), percent body fat, and VO2max as covariates for the entire group and a lean subgroup. The deconvolution method was used to characterize GH pulsatility from individual time points.

Results: GH varied through the day (P < 0.0001), with the highest concentrations overnight. BMI, percent body fat, and VO2max were related to GH concentrations in the entire group, whereas leptin predicted GH in the entire group as well as the lean subgroup of girls. Higher leptin was related to lower GH concentrations (P = 0.011), regardless of time. A log leptin level increase by 1 unit decreased GH by 27%. Pulsatility characteristics showed a 1-yr increase of age at menarche increasing total GH input by 20% (P = 0.0035) independently from BMI.

Conclusion: In postpubertal adolescent girls, leptin is related to GH concentration across the lean to overweight BMI spectrum. GH pulsatile secretion was greater in girls with later age at menarche.
The Growth Response to Growth Hormone (GH) Treatment in Children with Isolated GH Deficiency Is Independent of the Presence of the Exon 3-Minus Isoform of the GH Receptor
Authors: Blum Werner F. , Machinis Kalotina , Shavrikova Elena P. , Keller Alexandra , Stobbe Heike , Pfaeffle Roland W. , Amselem Serge
Published: July 2006

Context: A variant of the human GH receptor (GHR) lacks a 22-amino-acid sequence derived from exon 3 (d3-GHR). It was reported that pediatric patients, born small for gestational age or with idiopathic short stature who were homozygous or heterozygous for this variant responded better to GH treatment than those homozygous for the full-length allele (fl-GHR).

Objective: The objective was to study the impact of the GHR genotype on the phenotype and growth response in patients with isolated GH deficiency (IGHD) treated with GH.

Design: This was a retrospective, multinational, multicenter observational study.

Patients: Patients with IGHD (n = 107) were recruited.

Interventions: All patients received GH treatment at replacement doses. The GHR genotype (fl-GHR/fl-GHR, fl-GHR/d3-GHR, or d3-GHR/d3-GHR) was determined by PCR amplification.

Main Outcome Measures: Measures included height sd score, height velocity, height velocity sd score at baseline and 1 yr of GH treatment, and their changes.

Results: There was no statistically significant difference of the main outcome measures between patients with the d3-GHR allele (n = 48) and patients who were homozygous for the fl-GHR allele (n = 59). Moreover, the genotype group did not contribute significantly to the growth prediction in multiple linear regression models.

Conclusions: Our results indicate that the d3-GHR allele does not affect response to GH treatment or contribute to growth predictions in patients with IGHD who received replacement doses of GH aiming to restore a normal GH status. We did not confirm the previously reported data obtained in patients small for gestational age or with idiopathic short stature who received supraphysiological GH doses.
Complex biosynthesis of the muscle-enriched iron regulator RGMc
Authors: Kuninger David , Kuns-Hashimoto Robin , Kuzmickas Ryan , Rotwein Peter
Published: July 2006

The recently discovered repulsive guidance molecule c (RGMc or hemojuvelin) gene encodes a putative glycosylphosphatidylinositol (GPI)-anchored protein that is expressed in striated muscle and in liver. Mutations in this gene have been linked to the severe iron storage disease, juvenile hemochromatosis, although the mechanisms of action of RGMc in iron metabolism are unknown. As a first step toward understanding the molecular physiology of this protein, we studied its biosynthesis, processing and maturation. Production of RGMc occurs as an early and sustained event during skeletal muscle differentiation in culture and is secondary to RGMc gene activation. As assessed by pulse-chase studies and cell-surface labeling experiments, two classes of GPI-anchored and glycosylated RGMc molecules are targeted to the membrane and undergo distinct fates. Full-length RGMc is released from the cell surface and accumulates in extracellular fluid, where its half-life exceeds 24 hours. By contrast, the predominant membrane-associated isoform, a disulfide-linked heterodimer composed of N- and C-terminal fragments, is not found in the extracellular fluid, and is short-lived, as it disappears from the cell surface with a half-life of <3 hours after interruption of protein synthesis. A natural disease-associated RGMc mutant, with valine substituted for glycine at residue 320 (313 in mouse RGMc), does not undergo processing to generate the heterodimeric membrane-linked isoform of RGMc, and is found on the cell surface only as larger protein species. Our results define a series of biosynthetic steps leading to the normal production of different RGMc isoforms in cells, and provide a framework for understanding the biochemical basis of defects in the maturation of RGMc in juvenile hemochromatosis.
Cyclin-B1-mediated inhibition of excess separase is required for timely chromosome disjunction
Authors: Holland Andrew J. , Taylor Stephen S.
Published: July 2006

Separase, the cysteine protease that cleaves cohesin and thereby triggers chromosome disjunction, is inhibited by both securin- and phosphorylation-dependent cyclin B1 binding. Using a novel phosphorylation-specific antibody, we show that mitotic-specific phosphorylation of human separase on S1126 is required to establish, but not maintain, cyclin B1 binding. Cells expressing a non-phosphorylatable S1126A mutant maintain cohesion early in mitosis, aligning their chromosomes. Cohesion is then synchronously lost 5 minutes ahead of schedule, without degrading securin or cyclin B1. This premature chromatid disjunction requires the catalytic activity of separase, indicating that it is dependent on cohesin cleavage. Single chromatids then attempt to realign but the lack of tension results in unstable kinetochore-microtubule interactions and Aurora-B-dependent spindle checkpoint activation. Separase mutants that cannot bind cyclin B1 but are phosphorylated on S1126 phenocopy separase S1126A, indicating that cyclin B1 binding, rather than phosphorylation, is the key inhibitory event. Significantly, by overexpressing separase S1126A, we have simultaneously overridden the two known inhibitory mechanisms. First, by elevating separase levels above securin, securin-mediated inhibition is alleviated. Second, by preventing phosphorylation, cyclin-B1-mediated inhibition is also alleviated. Surprisingly, however, cohesion is maintained during the early stages of mitosis, indicating the existence of another mechanism that either inhibits separase or protects its substrate during early mitosis.
The Reduction of Sulfuric Acid by Hydrogen on Activated Carbon Impregnated with Copper Sulfate
Authors: Katagiri Akira , Watanabe Kiyoshi , Yoshizawa Shiro
Published: July 2006

The reduction of sulfuric acid has been studied for the purpose of the regeneration of activated carbon, which is used as an acceptor of sulfur dioxide from exhaust gas. When activated carbon impregnated with sulfuric acid was heated in a hydrogen atmosphere, sulfuric acid was reduced to sulfur dioxide by carbon in the temperature range from 200 °C to 350 °C. When copper sulfate was added, the sulfuric acid was reduced to sulfur dioxide, mainly by hydrogen, in the temperature range from 190 °C to 270 °C. At 227 °C, for example, the rate of reduction by hydrogen was nine times greater than the rate of reduction by carbon. Copper sulfate was sufficiently effective in an amount of one-fifth of the sulfuric acid in moles, indicating that copper in some form participates in the catalytic reaction.
The Role Played by Water in Spin State Variations among Nickel(II) Halide Complexes Containing (7R,14S)-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane
Authors: Ito Tasuku , Toriumi Koshiro , Ito Haruko
Published: July 2006

A complex dihydrate formed with nickel(II) bromide and the title macrocyclic ligand (memo-Me6[14]aneN4) crystallizes in triclinic space group P\bar1 and in orthorhombic space group Pcab. The crystal and molecular structures of the two crystal modifications have been determined by single crystal X-ray diffraction. In each compound, the nickel(II) is surrounded by a square-planar array of nitrogen atoms, giving low-spin complexes. In both compounds, water of crystallization and bromide ions are located above the hydrogen atoms of N–H groups and form hydrogen-bonded chelate rings of the type Ni–N–H···Br−···H–O···H–N. The N–H groups adjacent to the single methyl carbon and the geminal dimethyl carbon interact with bromide ion and water, respectively, in the P\bar1 form, whereas vice versa in the Pcab form. Water molecules in the present crystals and those in the previously reported crystal structure of [Ni(meso-Me6[14]aneN4)]Cl2·2H2O are involved in the same type of specific hydrogen-bonds. Because of the specific hydrogen-bonding effects, the presence of water prevents coordination of not only water itself but also halide ions, yielding thereby low-spin four coordinate complexes.
The Crystal and Molecular Structure of N-(Thioacetyl)tryptamine. A Radioprotective Indole Compound
Authors: Ishida Toshimasa , Shimizu Satomi , Inoue Masatoshi , Kitamura Kunihiro , Tomita Ken-ichi , Shinoda Masato
Published: July 2006

The crystal structure of N-(thioacetyl)tryptamine, a radioprotective agent, has been determined by the X-ray method. The crystal is monoclinic, space, group P21/c with the unit cell dimensions: a=23.761(5), b=5.553(1), c=8.889(2) Å, and β=94.04(4)°. The structure was solved by the direct method and succesive Fourier syntheses, and refined by the block-diagonal least-squares method to give a final R-value of 0.072. In the crystal, the molecules are held together with van der Waals contacts between the nonpolar groups of adjacent molecules, and an inter-molecular hydrogen bond between the sulfur and nitrogen atoms of the side chain (N–H···S=3.322 Å). The folded conformation observed in this compound could be related to the protection of DNA against irradiation.
α,β-Unsaturated Carboxylic Acid Derivatives. XIX. The Convenient Synthesis of α-Alkoxy-, α-Hydroxy-α-amino Acid, and Its Cyclic Dipeptide from α-Dehydroamino Acid
Authors: Shin Chung-gi , Sato Yoshiaki , Ohmatsu Hisao , Yoshimura Juji
Published: July 2006

The facile conversion of α-dehydroamino acid into α-alkoxy-α-amino acid and its cyclic dipeptide is described. The reaction of t-butyl 2-acetylamino-2-alkenoate or 1-benzyl-3-ethylidene-2,5-piperazinedione with alcohol, water, or acetic acid in the presence of NBS or NGS, followed by reduction with 10% Pd–C, gives t-butyl 2-alkoxy-, 2-hydroxy-, and 2-acetoxy-2-(acetylamino)alkanoates, and 3-alkoxy-3-ethyl-2,5-piperazinedione respectively. All the new compounds were characterized by spectroscopic analysis.
Enzymatic Oxidation of Alkyl Sulfides by Cytochrome P-450 and Hydroxyl Radical
Authors: Watanabe Yoshihito , Numata Tatsuo , Iyanagi Takashi , Oae Shigeru
Published: July 2006

The oxidation of alkyl sulfides, sulfoxides, and sulfones was examined with either rabbit liver microsomes or a reconstituted system containing purified cytochrome P-450, S-dealkylation being found to take place more readily with alkyl sulfides bearing a higher acidic α-hydrogen. Similar results were obtained in the oxidation of alkyl sulfides by hydroxyl radical. Both S-dealkylation and S-oxygenation products are presumed to be formed via the cation radical intermediate.
Synthesis and Electrical Resistivity of TCNQ Radical Anion Salts with 4,5-Disubstituted N,N-Dimethyl-1,3-dithiolan-2-iminium Cations
Authors: Kato Futoshi , Tanaka Toshio
Published: July 2006

The title salts with the formula [S–CHR1–CHR2–S–C=\overset+NMe2](TCNQ)n\ewdot (R1,R2=Me, H; Et, H; Ph, H; Me, Me; and Me, Br; n=1 and 2) were prepared. Electrical resistivities, electronic spectra, and magnetic susceptibilities of these salts in the solid state are reported.
The Effect of Polar Solvent on the 1JCH Spin-Spin Coupling Constants in Halomethanes and Haloethylenes
Authors: Watanabe Shosuke , Ando Isao
Published: July 2006

The solvent effect on the 13C–1H nuclear spin-spin coupling constants (1JCH) of halomethanes and haloethylenes is calculated by means of the finite perturbation theory based on the CNDO/2 approximations incorporating the ‘solvaton’ theory. The results of the calculation explained the tendency of the observed solvent effect data in the literature.
Uptake of Zinc Ion by Hydrous Manganese (IV) Oxide
Authors: Narita Eiichi , Okabe Taijiro
Published: July 2006

The uptake of zinc ion by hydrous manganese(IV) oxide in ammonium chloride solution containing zinc ion was investigated. The uptake of zinc ion was found to be proportional to the potassium content in the hydrous manganese(IV) oxide, the molar ratio of the sorbed Zn2+ to the released K+ being ca. 1 : 2.
Synthesis and Reactions of Perylenecarboxylic Acid Derivatives. VII. Hydrolysis of N,N′-Dialkyl-3,4 : 9,10-Perylenebis(dicarboximide) with Sulfuric Acid
Authors: Nagao Yukinori , Misono Takahisa
Published: July 2006

The hydrolysis of N,N′-dialkyl-3,4 : 9,10-perylenebis(dicarboximide) (alkyl=CH3, CH2CH3, CH2CH2CH3, and CH2CH2CH2CH3) with sulfuric acid at 180–200 °C gave N-alkyl-3,4 : 9,10-perylenetetracarboxylic monoanhydride monoimide (alkyl=CH3, CH2CH3, CH2CH2CH3, and CH2CH2CH2CH3). The kinetics of the reaction were determined spectroscopically.
Some Properties of Fluorine-adsorbed Active Carbon
Authors: Watanabe Nobuatsu , Ueno Kazuo
Published: July 2006

Properties of fluorine-adsorbed active carbon (FAAC), expected to be a new fluorinating agent, were investigated by means of TG, X-ray diffraction, and ESCA. The fluorine in FAAC was desorbed by heat treatment in a vacuum at temperatures higher than 200 °C. The X-ray diffraction and ESCA measurements suggest that fluorine is inserted between the carbon layer planes of the active carbon, and combines with carbon atoms weakly in comparison with the C–F covalent bond. The reactivity of FAAC against several organic compounds was studied. 1-Butanol, 1-butanethiol, and cyclohexylamine were oxidized. Butyryl chloride was fluorinated to give butyryl fluoride.
Conditional Monte Carlo Trajectory Calculation of Elementary Gas Reaction Rates
Authors: Minami Ryuichi , Okada Takashi
Published: July 2006

A new Monte Carlo trajectory method is proposed to estimate the rate constants of elementary molecular reactions. In this study, we have introduced the conditional Monte Carlo technique and obtained the following advantages. First, the procedure of calculation has been simplified. That is, the trajectory data have been accumulated as only one data set, from which the rate constants at any temperature have been reduced easily. Secondly, the necessary number of trajectories has been decreased by employing appropriate conditional distribution functions. Lastly, the error estimation has become possible on a reasonable base. This method has been applied to the (H2, H2) direct exchange reaction as an example and the result is reported briefly.
Catalytic Activity of Highly Dispersed Palladium. I. The Mechanism of Cyclohexene Hydrogenation and the Role of ZrO2 Support
Authors: Lee Bu Yong , Inoue Yasunobu , Yasumori Iwao
Published: July 2006

The hydrogenation of cyclohexene vapor on dispersed palladium was studied in the pressure range of 10–40 Torr at temperatures between 283 and 323 K. Palladium was impregnated on ZrO2 and α-Al2O3 over the wide range of 0.03 to 2.1 wt%, and the percentage exposed was varied from 13 to 96% for Pd/ZrO2 and from 2 to 15% for Pd/α-Al2O3. The hydrogenation activity, Vg, per unit of weight of the Pd dispersed on ZrO2, exhibited a sharp maximum at 0.05 wt%, but the turn-over frequency, Vs, per exposed atom around this maximum remained almost constant, which shows the reaction to be structure-insensitive. The value of Vs for Pd/ZrO2 at 301 K was larger than those for Pd/α-Al2O3 and Pd bulk metal by one order of magnitude. The ZrO2 carrier affected the catalytic behavior of palladium; the reaction orders with respect to the hydrogen and cyclohexene pressures changed to 0.73±0.04 and 0.64±0.04 respectively from the corresponding values, 0.97±0.03 and 0.07±0.04 for Pd/α-Al2O3 and Pd metal. The deuterium distributions in the reactant and product molecules in the reaction with D2 suggested that the hydrogenation on Pd/ZrO2 and Pd/α-Al2O3 proceeds via the associative mechanism ; the slow step is assumed to be the reaction of the surface cyclohexyl radical with the adsorbed hydrogen atom. The poisoning due to preadsorbed CO decreased the catalytic activities of Pd/ZrO2 and Pd/α-Al2O3 almost linearly with the amounts of surface CO and caused a complete deactivation at about a half coverage of the surface Pd atoms, irrespective of the percentage exposed. On the basis of these results, the structure-insensitivity of the cyclohexene hydrogenation on Pd and the carrier effect of ZrO2 are discussed.
Intermolecular Potential, Vibrational Spectra, and Structures of Amino Acid Crystals. II. α-Glycine, l-Alanine, and Dl-Alanine Crystals
Authors: Machida Katsunosuke , Kagayama Akira , Kuroda Yoshihiro
Published: July 2006

The lattice energies, the deviations of the structure parameters from the model equilibrium, the molecular distortions due to the intermolecular interaction and the vibrational frequencies of α-glycine, l-alanine and Dl-alanine crystals were calculated from three sets of parameters for the pairwise atom-atom interaction potential functions. By comparing the calculated quantities with the observed ones, the combination of the exp-6 type non-bonded potential and the Lippincott type hydrogen bond stretching potential is shown to afford a better model of the intermolecular interaction in these crystals than the combination of the Lennard-Jones 6-12 potential and the general hydrogen bond 10-12 potential.
Adsorption of Neutral α-Amino Acids at the Mercury-Aqueous Solution Interface and Hydrophobicity Scales of Amino Acid Side Chains at the Electrified Interfaces
Authors: Kakiuchi Takashi , Senda Mitsugi
Published: July 2006

The adsorption of glycine, Dl-serine, l-threonine, l-asparagine, l-glutamine, l-valine, l-leucine, l-methionine, and l-tryptophan at the mercury-aqueous sodium fluoride solution interface has been studied by measuring differential capacities, potentials of zero charge, pzc, and surface tensions at the pzc. The standard adsorption free energies for these amino acids and for the amino acids previously studied have been used to deduce hydrophobicity scales of amino acid side chains at positively charged, negatively charged, and uncharged interfaces. The hydrophobicity scale at the uncharged interface was basically similar to that of Nozaki and Tanford. When the surface was charged positively, the positions of serine and alanine, and of threonine and α-aminobutyric acid, in the scale were reversed. This reversion was primarily ascribed to the difference in the positions of maximum adsorption potentials between the amino acids with an aliphatic side chain and those with a hydroxyl group in the side chain.
The Effect of Iron(III) on the Cadmium Ion-selective Electrode
Authors: Sakura Sachiko , Virtanen Rauno
Published: July 2006

Iron(III) interferes with the operation of a cadmium, lead and copper ion-selective electrode. The cadmium ion-selective electrode (CdS/Ag2S) showed a potential shift to the positive direction of more than 100 mV for a decade change of iron(III) concentration. However, the exact mechanism for this interference is not known, though it is expected to be the oxidation of sulfide ion by Fe(III). The mechanism of interference by iron(III) was studied by using the cadmium ion-selective electrode, flow-through cell, pH buffer solutions, potentiometric titrations, and atomic absorption spectrophotometry measurements. It was found that iron(III) promotes dissolution reaction of cadmium ions from the solid cadmium sulfide electrode and that flow conditions of samples have no effect on the iron(III) interference.
The Determination of Alkaline Phosphatase Activity in Serum by Means of Flow-through Analysis with an Ion-selective Electrode
Authors: Hara Tadashi , Imaki Masakatsu , Toriyama Motohiro
Published: July 2006

In order to determine continuously the alkaline phosphatase activity in a serum sample, a potentiometric method using a newly prepared phosphate ion-selective electrode has been established by the authors for the first time. The alkaline phosphatase activity was determined by measuring the concentration of the phosphate ion which was liberated by the enzymatic hydrolysis of disodium phenyl phosphate in the presence of alkaline phosphatase. The measurement of the phosphate ion with an ion-selective electrode was seriously interfered with by protein and the halide ion, but the interference could be removed by covering the electrode surface with a cellulose acetate membrane and by separating the chloride ion from a serum sample by gel chromatography. The present method was applied to the determination of alkaline phosphatase activity in serum; the results obtained showed a satisfactory correlation with those obtained by the conventional method. The method was found to be useful for practical diagnosis based on the activity of alkaline phosphatase.
Anomalous Solvatochromism of Charge-transfer Absorption Bands
Authors: Aihara Jun-ichi
Published: July 2006

When n-donor solvents are employed, charge-tansfer absorption bands become broader on the low-energy side, the absorption peaks shifting toward the high-energy side. This type of solvatochromism has an analogy with that of the n-π* transitions.
The Methylation of Ribonucleosides by Trimethyl Phosphate or Dimethyl Sulfate in the Presence of Boric Acid
Authors: Hisanaga Yorisato , Tanabe Toshizumi , Yamauchi Kiyoshi , Kinoshita Masayoshi
Published: July 2006

Uridine, inosine, adenosine, and thymidine were methylated selectively at the base moieties by the use of trimethyl phosphate or dimethyl sulfate in the presence of boric acid. A suppressing effect of boric acid on the methylation of the ribose-hydroxyl groups was discussed briefly.
The Adsorption of Basic α-Amino Acids in an Aqueous Solution by Titanium(IV) Oxide
Authors: Okazaki Susumu , Aoki Teruaki , Tani Koichi
Published: July 2006

TiO2 showed a pronounced activity in the adsorption of basic α-amino acids, such as l-lysine and l-arginine, in an aqueous solution. The adsorptive activity of TiO2 containing sulfate ions was lower than that of the sulfate ion-free TiO2, and it was suppressed by phosphate ions. The pH of the aqueous solution hardly affected the adsorption, while the heat-treatment of TiO2 above 500 °C noticeably lowered the adsorption. The Langmuir equation was applicable to the adsorption of l-lysine, showing that the amount of saturated adsorption was about 0.7 mmol/g TiO2 heat-treated at 500 °C. The heat of adsorption of l-lysine, as determined from the adsorption isotherms at 10, 30, and 50 °C, was 2257 J/mol. A linear relationship was observed between the amount of l-lysine adsorbed and that of the surface OH groups.
The Crystal and Molecular Structure of the Photodimer of Biphenylene
Authors: Furusaki Akio , Hashiba Nobuhiro , Matsumoto Takeshi , Aotsuka Tomoji , Nishida Shinya
Published: July 2006

The molecular structure of the photodimer of biphenylene has been determined by X-ray crystal analysis. The crystals are triclinic, with eight molecules in a unit cell with dimensions of a=15.061, b=17.687, c=13.091 Å, α=108.91, β=98.52, and γ=89.71°; the space group is P\bar1. 6625 unique intensity data were collected on a four-circle diffractometer with LiF-monochromated Cu Kα radiation. The structure was solved by the symbolic-addition method using 8 symbols, and refined by the block-diagonal least-squares method. The final R value was 0.101. The molecular structure thus obtained corresponds to syn-13,14 : 15,16-dibenzotricyclo[6.4.2.22,7]hexadeca-1,3,5,7,9,11,13,15-octaene. Of the four crystallographically-independent molecules, two have approximately the C2v symmetry, while the remaining two are somewhat deformed, their symmetry being nearly C2. The molecules are held together mainly by van der Waals interactions.
Studies on Electrode Processes of Stabilized Zirconia Cell System by Complex Impedance Method
Authors: Sasaki Jun , Mizusaki Junichiro , Yamauchi Shigeru , Fueki Kazuo
Published: July 2006

Three kinds of materials, Pt, Ag, and La0.5Sr0.5CoO3, were applied to stabilized zirconia as electrodes and the electrode behavior was investigated by means of the complex impedance method. The impedance arc due to the electrode/stabilized zirconia interface was always depressed semi-circles. Impedance behavior was strongly dependent on the electrode materials. Assuming that the impedance arc could be interpreted by a parallel R-C circuit, the interface resistance Ri and the interface capacitance Ci were determined. The apparent activation energy determined from the slope of the plots of logRi  vs. 1/T was nearly the same for the same electrode material. (Ag electrode: 92 kJ/mol and Pt electrode: 201 kJ/mol). The oxygen pressure dependence of Ci and Ri was also investigated. Although Ci was virtually independent of the oxygen partial pressure PO2, Ri was proportional to PO2−2⁄3 for Ag electrodes and PO2−1⁄4 for Pt electrodes. The rate-determining step was supposed to be the dissociation of oxygen molecules into atoms for Ag electrodes, and the dissociation of oxygen molecules or one of the subsequent steps for Pt electrodes.
Syntheses and Characterizations of μ-Dicarboxylato-bis[pentaamminecobalt(III)] Complexes
Authors: Ogino Hiroshi , Tsukahara Keiichi , Morioka Yoshiyuki , Tanaka Nobuyuki
Published: July 2006

Five new complexes, [(NH3)5Co(dicarboxylate)Co(NH3)5]X4 (dicarboxylate=oxalate, succinate, pimelate, fumarate, and maleate; X=ClO4− or Cl−), were synthesized by the reactions of [Co(hydrogen dicarboxylate)(NH3)5](ClO4)2 with [Co(NH3)5(H2O)](ClO4)3 and characterized by chromatographic behavior and electronic and NMR techniques. When maleate was used as the dicarboxylate, the formation of [(NH3)5Co(fumarate)Co(NH3)5]4+ as well as [(NH3)5Co(maleate)Co(NH3)5]4+ was observed. The IR and Raman spectra of [(NH3)5Co(oxalate)Co(NH3)5]4+ indicate that the symmetry of the oxalate ion in the complex may be approximated by D2h.
Multiple Paths for Photo-alkylation and -alkoxylation of 3-Pyridinecarboxylic Ester in Alcohol. Simultaneous Contribution of Several Kinds of Excited States
Authors: Sugimori Akira , Tobita Etsuo , Kumagai Yasuyuki , Satô Gen P
Published: July 2006

UV-irradiation of methyl 3-pyridinecarboxylate (1) in acidic alcoholic solutions brings about the alkoxylation and alkylation at the pyridine ring. Photoalkylation occurs in several paths: 1) alkylation initiated by the triplet π-π* state, 2) alkylation initiated by the triplet n-π* state of the carbonyl moiety of the ester group, 3) alkylation initiated by an exciplex between a free base form of 1 and a pyridinium form of 1, and 4) alkylation promoted by chloride ions. Photoalkoxylation originates from a singlet excited state of 1. In the photoreactions of 1 in strongly acidic methanolic solutions acidified with H2SO4, three kinds of excited states (two kinds of triplet states for alkylation and a singlet state for alkoxylation) contribute simultaneously.
Cyclization of Isothiosemicarbazones. IV. Synthesis of the [1,2,4]Triazolo[1,5-c]pyrimidine Ring System
Authors: Yamazaki Chiji
Published: July 2006

Condensation of isothiosemicarbazones with ethoxymethylenemalononitrile gave 2,3-dihydro[1,2,4] triazolo[1,5-c]pyrimidines in moderate to high yields. The 2,3-dihydro compounds were readily oxidized in dimethyl sulfoxide to give the corresponding [1,2,4]triazolo[1,5-c]pyrimidines.
Kinetic Studies of the Stripping of Bis(2,4-pentanedionato)beryllium in Various Liquid-Liquid Partition Systems
Authors: Watarai Hitoshi , Suzuki Nobuo
Published: July 2006

The rate constant, kst, for the stripping of bis(2,4-pentanedionato)beryllium from inert solvents into water or a mixed solvent of water with a miscible organic solvent, such as ethylene glycol, methanol, acetonitrile, and pimethyl sulfoxide, was determined and discussed in connection with the dissociation rate constant, kd, of the chelate in the aqueous phase and the liquid-liquid partition coefficient, P, of the chelate. The kst=kd⁄(1+P) relationship was found to hold true in all systems studied. The solvent effect of the aqueous mixed solvents on kd was discussed in terms of the transfer activity coefficient.
Synthesis of Oxazolidines, Thiazolidines, and 5,6,7,8-Tetrahydro-1H,3H-pyrrolo[1,2-c]oxazole (or thiazole)-1,3-diones from β-Hydroxy- or β-Mercapto-α-amino Acid Esters
Authors: Badr Mahmoud Zarif Amin , Aly Morsy Mohamed , Fahmy Atiat Mohamed , Mansour Mansour Esmael Younis
Published: July 2006

2-Aryl-4-(ethoxycarbonyl)oxazolidines and thiazolidines (1) were prepared from the corresponding α-amino acid ethyl esters containing either hydroxyl or mercapto groups in the β-position by fusion with some aromatic aldehydes. Dehydrogenation of 1 with N-bromosuccinimide gave the corresponding oxazoles and thiazoles. The oxazolidines and thiazolidines gave Mannich bases on interaction with p-nitrobenzaldehyde and piperidine. Acetylation of 1 gave the corresponding N-acetylderivatives, which on fusion in the presence of anhydrous ZnCl2 undergo cyclization, giving the corresponding bicyclic compounds, 5,6,7,8-tetrahydro-1H,3H-pyrrolo[1,2-c]oxazole (or thiazole)-1,3-diones.
Kinetics and Mechanism of Hydrolysis of Ruheman’s Purple in the Absence and Presence of Micelles in Aqueous Medium
Authors: Malaviya Sudhir , Katiyar Sarvagya S
Published: July 2006

The mechanism of acid hydrolysis of Ruheman’s purple has been investigated and the effect of micelles on the rate has been examined. First order rate constant for the hydrolysis reaction decreases linearly with decreasing hydrogen ion concentration up to pH 3 and levels off thereafter with no reaction occurring above pH 7. Increasing ionic strength decreases the rate in accordance with the Bronsted-Christiansen equation. The salt effect in the dipole-dipole reaction is probably a reflection of the fast equilibrium steps involving ions preceding the rate-determining step. Solvents like ethylene glycol and dioxane have no effect, indicating that the rate-determining step of the reaction does not involve ionic species. A mechanism of the reaction has been proposed which is consistent with our observed results. In the presence of micelles the reaction rate was strongly inhibited by the cationic micelles of hexadecyltrimethylammonium bromide, whereas anionic micelles of sodium dodecyl sulfate showed a slight enhancement. The micellar data have been analyzed on the basis of available models.
Reductive Elimination of d8-Organotransition Metal Complexes
Authors: Tatsumi Kazuyuki , Hoffmann Roald , Yamamoto Akio , Stille John K
Published: July 2006

A theoretical analysis of two aspects of the mechanism of reductive elimination is presented—how the choice of central metal and peripheral ligands affects the activation energy for reductive elimination from a four-coordinate MR2(PR3)2 complex and how ligand asymmetry controls cis-trans rearrangements and elimination pathways proceeding through three-coordinate intermediates. The following conclusions emerge: (1) In the four-coordinate complex, the better the σ-donating capability of the leaving groups, the more facile the elimination; (2) Stronger donor ligands trans to the leaving groups will increase the barrier to elimination; (3) The reductive elimination barrier in four-coordinate complexes is controlled by the energy of an antisymmetric b2 orbital, which in turn depends on the energy of the metal levels. The activation energy for such direct reductive elimination should be, and is, substantially lower for Ni than for Pt or Pd; (4) T-shaped trans PdLR2, arising from dissociation of L in PdL2R2, will encounter a substantial barrier to polytopal rearrangement to cis PdLR2, which in turn has an open channel for reductive elimination of R2; (5) If the leaving groups are poor donors, cis-trans isomerization in the three-coordinate manifold should be easier than elimination.
The Spectrophotometric Determination of Zirconium(IV) by Solvent Extraction with Trioctylphosphine Oxide and Benzophenone
Authors: Shigetomi Yasumasa , Kojima Takehiro
Published: July 2006

The colorimetric determination of zirconium(IV) was investigated by means of liquid-liquid extraction, where zirconium in a nitric-acid solution was quantitatively extracted into molten TOPO-benzophenone at about 60 °C. The organic phase solidifies on cooling and is separated and dissolved in methanol. The addition of an ethanolic solution of 1-(2-pyridylazo)-2-naphthol to this solution yields as intense red colour.
Amination Kinetics of Chloromethylated Polystyrene Accompanied by Acceleration and Deceleration
Authors: Kawabe Hiroshi
Published: July 2006

Procedures to evaluate rigorously the rate constants in the animations of chloromethylated polystyrene which are accompanied by acceleration and deceleration have been developed. The calculated fractional conversions in the reaction of chloromethylated polystyrene with 2-amino-1-butanol in dioxane, accompanied by acceleration, and the reaction with triethylamine in dimethyl sulfoxide, accompanied by deceleration, are proved to be in good agreement with the observed ones. The activation parameters of these reactions, in addition to the kinetic data in N,N-dimethylformamide, support the conclusion that the acceleration and the deceleration are due to the formation of the hydrogen bond and to the electrostatic effect from the neighboring groups in the respective transition states.
Collision Induced Perturbations on the Long-lived Fluorescence of Pyrazine in S1
Authors: Igarashi Hisao , Kaya Koji
Published: July 2006

Collision induced intersystem crossing (slow fluorescence quenching and phosphorescence induction) from selected vibronic levels of pyrazine in S1(nπ*, B3u) was investigated. It was found that slow fluorescence quenching rate at the zero point level exceeds the hard sphere collision rate several times and rapidly approaches it as the excitation energy is increased. On the other hand, phosphorescence induction rate was found to be nearly equal to the collision rate and to have little excitation energy dependence. These differences were discussed on the basis of the collision induced relaxation mechanisms.
Encapsulation of Krypton with (K, MII)-A Zeolites
Authors: Itabashi Keiji , Takaishi Tetsuo , Ohgushi Tatsuo
Published: July 2006

The encapsulation of krypton is realized with zeolite A, having compositions (K12−2xMxII-A with 1.11≤x≤3.78, at temperatures lower than 300 °C and a pressure of 3.7×106 Pa. This encapsulation condition is much milder than the usual one, 350 °C and 4.2×108 Pa, which is adopted in industry. Such lowerings of the encapsulation temperature and pressure are caused by bivalent cations introduced through ion-exchanges. The result is an experimental evidence to the existence of the ion-loosening effect proposed in preceding papers.
Determination of Thermodynamic Properties of Gibbsite from Its Solubility Data in NaOH Solutions
Authors: Chang Byong-Tae
Published: July 2006

A reasonable method for determination of thermodynamic properties of alumina hydrates from their solubility data in alkaline pH range was presented and applied to the solubility data of gibbsite in NaOH solutions with success. When log(Ks⁄aw), where Ks=mHmAl and aw is the activity of water, was plotted against a Debye-Hiickel function of the ionic strength I, I1⁄2⁄(1+BtalI1⁄2), a linear relationship to moderately high ionic strengths was found over the range of temperatures from 40 to 110 °C, having the theoretical Debye-Hiickel limiting slope and the intercept of logKs° at I=0. Assuming the same ionic size parameters, a1=a2, the solubility product (Ks°) of gibbsite was found to depend upon temperature up to 110 °C as follows: logKs°=−4064⁄T−1.54 or −4023⁄T−1.65. At high ionic strengths above 1.0, log(Ks⁄aw) showed positive deviations from the straight line, which may be attributed to the formation of complex ions, e.g., Al2O(OH)62−, or the dehydration of Al(OH)4− to AlO(OH)2− and AlO2− ions.
Negative Ions Formed by Vacuum Spark Discharge. III. Polyatomic Negative Ions of the Elements in A-Subgroups on the Periodic Table
Authors: Kishi Hiroshi
Published: July 2006

Polyatomic negative ions for almost all of the elements in A-subgroups on the periodic table were tested by the spark discharge type ion source mass spectroscopy. A large number of polyatomic negative ions such as “polymer” negative ions, hydride negative ions, oxide negative ions, and carbide negative ions, could be detected. The results are discussed with reference to the reported values of electron affinities of the molecules and to the reported results by other methods of formation.
Negative Ions Formed by Vacuum Spark Discharge. IV . Polyatomic Negative Ions of the Elements in B-Subgroups on the Periodic Table
Authors: Kishi Hiroshi
Published: July 2006

Polyatomic negative ions for almost all of the elements in B-subgroups on the periodic table were tested by the spark discharge type ion source mass spectroscopy. Polyatomic negative ions such as hydride negative ions, oxide negative ions, and carbide negative ions could be detected. The results are discussed with reference to the reported results by other methods of formation.
Digitally Controlled Automatic Coulometric Karl Fischer Titrator
Authors: Umemoto Kisaburo
Published: July 2006

An automatic coulometric Karl Fischer titrator capable of direct readout of the water titrated and the background of titration was constructed. Control of the generation of reagent was carried out by a digital counting method. The over- and under-titration was minimized by holding the level of reagent at the start and the end of titration as close as possible. Details of the circuit configuration were presented. The precision of determination was ca. ±2 μg and ±1–±2 μg for the automatic titration of 1 mg and 10–500 μg of water, respectively. Water of less than 20 μg was titrated within a precision of 1 μg by watching the drift and subsequent recovery of the blank level.
Prerequisites for the Enhancement of Formose Formation in the Presence of Hydroxy Oxo Compounds
Authors: Sakai Tomoya , Ishizaki Masahiko , Kobayashi Katsuaki , Goto Masafumi
Published: July 2006

The enhancement of formose formation in the presence of several hydroxy oxo compounds was examined in an aqueous Ca(OH)2 solution. Four terminal hydroxy oxo compounds, 2-hydroxyacetophenone, 1,3-dihydroxyacetone, Dl-glyceraldehyde, and d-glucose, were confirmed to accelerate the reaction, but two internal hydroxy oxo compounds, 2-hydroxypropiophenone and acetoin, were found not to be effective. The acceleration efficiency was larger for a system in which hydroxy oxo compounds were introduced to an aqueous mixture of Ca(OH)2 and formaldehyde than for a system in which formaldehyde was introduced to an aqueous mixture of Ca(OH)2 and the hydroxy oxo compounds. The difference in the acceleration efficiencies between the two procedures of reagent introduction was large for 2-hydroxyacetophenone and 1,3-dihydroxyacetone. This is accounted for by the rapid conversions of the added hydroxy oxo compounds in an aqueous Ca(OH)2 solution.
Structure and Synthesis of (+)-Shonanol
Authors: Matsumoto Takashi , Imai Sachihiko , Kawashima Hiroyuki , Mitsuki Masanori
Published: July 2006

The structure of shonanol was restudied and found to be 12-hydroxyabieta-2,8,11,13-tetraen-1-one (1) by the following synthesis. A Grignard reaction of methyl (+)-12-methoxyabieta-8,11,13-trien-18-oate with phenylmagnesium bromide, followed by treatment with lead tetraacetate and calcium carbonate afforded a mixture of Δ3−, Δ4−, and Δ4(18)-19-nor compounds. This was oxidized with selenium dioxide to give (+)-12-methoxy19-norabieta-4(18),8,11,13-tetraen-3α-ol. This alcohol was converted to (+)-12-methoxyabieta-5,8,11,13-tetraen-3-one (6) by the known procedure. Reduction of 6 with lithium aluminium hydride, followed by catalytic hydrogenation, yielded (+)-12-methoxyabieta-8,11,13-trien-3β-ol (8) and a small amount of its cis isomer. The compound (8) was then converted to (+)-12-methoxyabieta-1,8,11,13-tetraen-3-one (12) by a series of reactions: oxidation with pyridinium chlorochromate, bromination with pyridinium tribromide, and dehydrobromination with lithium carbonate and lithium bromide. Demethylation of 12 with boron tribromide gave (+)-12-hydroxyabieta-1,8,11,13-tetraen-3-one. Oxidation of 12 with alkaline hydrogen peroxide, followed by treatment with hydrazine hydrate, gave (+)-12-methoxyabieta-2,8,11,13-tetraen-1α-ol; this was oxidized with Jones reagent to give the corresponding 1-oxo compound. The 1-oxo compound was finally demethylated with boron tribromide to yield (+)-1, whose spectra were identical with those of natural shonanol.
Enzymatic Synthesis of New Pyridine Nucleosides. Clitidine and Its Amide Derivative
Authors: Tono-oka Shuichi , Sasahara Yasuhiko , Sasaki Akio , Shirahama Haruhisa , Matsumoto Takeshi , Kakimoto Shichiro
Published: July 2006

Two β-NAD-analogs were prepared utilizing a base-exchange reaction catalyzed by pig-brain NADase. These analogs were proved to contain a methyl 1,4-dihydro-4-iminonicotinate and a 1,4-dihydro-4-iminonicotinamide moiety. By successive hydrolytic degradations of these analogs, 1,4-dihydro-4-iminopyridine β-ribosides with 3-carboxyl and 3-carbamoyl groups were prepared in good yields. The former compound was identical with clitidine, a toxic pyridine nucleoside recently isolated from a toadstool. The present synthesis confirmed the 1,4-dihydro-4-imino β-riboside structure of clitidine. Preliminary biological tests showed that the 3-carbamoyl compound was more toxic than clitidine, suggesting that the amide derivative of clitidine is an essential toxic substance in the toadstool.
The Pormylation of an Aromatic Nucleus by the Use of 2-Ethoxy-1,3-dithiolane
Authors: Jo Shigeo , Tanimoto Shigeo , Sugimoto Toyonari , Okano Masaya
Published: July 2006

The reaction of various phenols with 2-ethoxy-1,3-dithiolane proceeded smoothly in the presence of BF3·Et2O to afford 1,3-dithiolan-2-ylated phenols, which were readily hydrolyzed to the corresponding aldehydes. This process was also extended to N,N-dimethylaniline and indole.
The Acid-catalyzed Decomposition of α-Diazo β-Hydroxy Ketones
Authors: Miyauchi Kazuo , Hori Kimiaki , Hirai Tsuguji , Takebayashi Matsuji , Ibata Toshikazu
Published: July 2006

The proton acid-catalyzed decomposition of 3-aryl-2-diazo-3-hydroxy-1-phenylpropanone (1) gave aryl and hydrogen migration products. The former was the enol-form (2) of 2-aryl-3-phenyl-1,3-propanedione and the latter was the enol- (3) and keto-form (4) of 1-aryl-3-phenyl-1,3-propanedione. The product ratios, 2/(3+4), were affected by the catalysts and solvents used. More polar solvents favored the formation of aryl migration products (2). On the other hand, the BF3-catalyzed decomposition of 1 gave acetylenic ketones as main products along with 2, 3, and 4. The TsOH-catalyzed decomposition of 2-diazo-3-hydroxy-3-phenyl-1-indanone, (cyclic α-diazo β-hydroxy ketone), gave 2-phenyl-1,3-indandione quantitatively through phenyl migration.
Transfer Free Energies of Fluoride Ion in Aqueous Mixtures of Some Organic Solvents
Authors: Bhattacharya Abhijit , Das Kaushik , Das Asim Kumar , Kundu Kiron Kumar
Published: July 2006

Standard free energies of transfer, ΔGt°, of potassium fluoride (KF) from water to aqueous mixtures of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetonitrile (ACN), 1,2-dimethoxyethane (DME), and 2-methoxyethanol (ME) have been determined at 25 °C from emf measurements performed on the double cell: Pb(Hg)–PbF2/KF(m), solvent/K(Hg)/KF(m), water/PbF2–Pb(Hg). ΔGt° values of F− were obtained from these values using the corresponding values of K+, as obtained earlier by use of tetraphenylarsonium tetraphenylborate reference electrolyte assumption. In each solvent system ΔGt°(F−) values are found to be increasingly positive with cosolvent composition reflecting the pronounced destabilization of F− and their relative order : DME>DMSO≥DMF>>ACN≈ME conforms to what is expected from the relative ‘aproticity’ of the dipolar aprotic cosolvents and that induced in the protic ME by the possible intramolecular H-bonding. The observed larger destabilization of F− compared to OH− in ME–water system has been attributed to the H-bonding effect of the protic cosolvent ME and the reverse behaviour in DME–water and DMSO–water systems to the absence of such effect of these cosolvents. Moreover, tests of Feakins-type extrapolation for assigning individual ion contribution using ΔGt°(KF) values along with those of other potassium halides, provided some important reflections on the inadequacy of such plots made without the data points of F−.
14N Nuclear Quadrupole Resonance Spectra of K2SrCu(NO2)6, K2BaCu(NO2)6, and Cs2PbCu(NO2)6
Authors: Asaji Tetsuo , Ishikawa Jun , Ikeda Ryuichi , Nakamura Daiyu
Published: July 2006

The 14N NQR frequencies of K2SrCu(NO2)6, K2BaCu(NO2)6, and Cs2PbCu(NO2)6 were determined at various temperatures below about 155, 67, and 235 K, respectively. The results are discussed in referring to their crystal structure.