bluuebunny/crossref_metadata_2025 huggingface dataset:
Photocatalyzed Decomposition of 4-Chlorophenol by Keggin-Type Heteropolytungstate
Authors: Einaga Hisahiro , Misono Makoto
Published: June 2006

The photocatalytic decomposition of 4-chlorophenol with a Keggin-type heteropolytungstate, PW12O403− (abbreviated as PW123−), under aerated conditions has been investigated in an aqueous or water-acetonitrile solution by using a 300 W Xe arc lamp at 303 K. The kinetics of the reaction indicated that the reaction proceeds via a Langmuir–Hinshelwood (or Michaelis–Menten) type mechanism, in which the complexation between the heteropolyanion and 4-chlorophenol exists as a pre-equilibrium step. This complex formation was evidenced by the observation of a new band at λ < 650 nm and the enhancement of the solubility of 4-chlorophenol in water in the presence of PW123−. The intensity of the new band varied in parallel with the reaction rate, depending on the concentrations of 4-chlorophenol and acetonitrile. This fact was consistent with the mechanism proposed.
Effect of Mastoparan on the Binding of Ca2+ to S-100 Proteins in the Presence of Zn2+
Authors: Matsuda Sadayuki
Published: June 2006

S-100 proteins, which are acidic Ca2+-binding proteins, exist in the brain and modulate enzymes and proteins as does calmodulin. In order to clarify some unique characteristics of S-100 proteins, the effects of mastoparan (MP) on the Ca2+ affinity of two S-100 protein isoforms (S-100a.a′, S-100b) in the presence of Zn2+ were examined using dialysis and stopped-flow methods. It was clearly demonstrated that the enhancement of S-100a.a′ was distinct from that of S-100b. Although the former isoform was affected only by the addition of MP, the latter was affected by MP or Zn2+.
The Inhibitory Capability of Decorative Plated Coatings for the Growth of Bacteria
Authors: Zhao Zhi-hong , Hasebe Kazuyuki , Sakagami Yoshikazu , Osaka Tetsuya
Published: June 2006

The antibacterial activity of various electroplated coatings (cobalt, zinc, copper, and cobalt-containing alloys of nickel, zinc, chromium) was determined by a “Drop-method” antibacterial experiment against pathogenic bacteria (gram-positive bacterial S. aureus, MRSA, and gram-negative bacteria E. coli, P. aeruginosa). It was found that all of them possessed a higher antibacterial activity than stainless steel. The ralationship between the inhibitory capability for the growth of bacteria and the rest potential of the electroplated coatings was also investigated. A significant antibacterial activity of the coatings was apparently displayed by a rest-potential shift to more negative values. It was suggested that all of the tested bacteria fell closely within the lethal range when the rest potentials were lower than -543 mV. However, some amount of metal ions dissolved from various from various electroplated coatings was measured; accordingly, the inhibitory capability of the simulated dissolution concentrations of metal ions the growth of bacteria is discussed.
Stereochemical Control in Microbial Reduction. XXIX. Mechanism of Stereochemical Control with an Additive in the Diastereoselective Reduction by Geotrichum candidum
Authors: Kawai Yasushi , Takanobe Kousuke , Ohno Atsuyoshi
Published: June 2006

The reduction of ethyl 2-methyl-3-oxobutanoate with Geotrichum candidum yields approximately equal amounts of the corresponding syn-(2R,3S)- and anti-(2S,3S)-3-hydroxy esters. When the microbe is incubated with methyl vinyl ketone (MVK) or chloroacetone before it is subjected to the reduction, the corresponding anti-(2S,3S)-hydroxy ester is obtained with exclusive enantio- as well as diastereoselectivity. In order to obtain more insight into the mechanism of this stereochemical control in microbial reduction, β-keto ester reductases were isolated and purified from the cells of G. candidum. Three dominantly competing enzymes were purified. One of them affords the anti-(2S,3S)-hydroxy ester selectively, whereas the others give the syn-(2R,3S)-hydroxy ester selectively. The rates of enzymatic reductions were measured in the presence and absence of an additive. Chloroacetone and MVK are competitive and suicide substrates, respectively, for the syn-enzymes, whereas they hardly affect the activity of the anti-enzyme. In the presence of an additive, the reduction of ethyl 2-methyl-3-oxobutanoate with G. candidum is catalyzed by the anti-enzyme only.
Synthesis and Properties of High-Molecular-Weight Polypeptides Containing Tryptophan III. Synthesis and Properties of Copolypeptides Containing 1-Nin-Formyltryptophan with Alanine
Authors: Uchida Chieko , Wakamatsu Kaori , Iizuka Yasuko , Oguma Kouki , Oya Masanao
Published: June 2006

N-Carboxy-Nin-formyltryptophan anhydride (4-(l-1-Nin-formylindol-3-ylmethyl)-2,5-oxazolidine dione, Trp(Form) NCA) was synthesized by formylation of the indole group of tryptophan, followed by N-carboxylation. The reactivity of copolymerization of Trp(Form) NCA with N-carboxy-l-alanine anhydride (4-methyl-1-2,5-oxazolidinedione, l-Ala NCA) was higher than that of Trp NCA. The helix contents of the formed copolypeptides, estimated by CD spectra, were remarkably decreased at a content of about 27% of Trp(Form). The content of Trp(Form) residue needed to destroy helix conformation in the copolypeptides was more than that of Trp residue of 8%.
Photocatalytic Formations of Patterning Dye Films with TiO2 Particles Based on Chromogenic Development of Photography
Authors: Liu Shunlin , Saji Tetsuo
Published: June 2006

Patterning dye films were obtained on a transparent polyester plate by ultraviolet (UV) light illumination of an alkaline suspension containing TiO2 particles, methylviologen dichloride (MVCl2), N,N-p-phenylenediamine (PPD), and coupler. The patterning films formed are of high resolution (10 μm). Influences of light intensity (Φ), amount of TiO2 particles, solution acidity, and illumination time on the film formation were studied. Regeneration of MV2+ by oxygen was found to be important for film formation.
pH-Modulated Vectorial Electron Transfer Reactions at a Self-Assembled Monolayer on a Gold Electrode
Authors: Nakashima Naotoshi , Deguchi Yonekazu
Published: June 2006

A self-assembled monolayer of 1-dodecanethiol (C12SH) on a gold electrode was prepared by dipping a polished bare electrode into an ethanolic solution of C12SH (1.0 mmol dm−3) for 10 min. The obtained modified electrode blocked the direct electron-transfer reaction of [Fe(CN)6]3− and [Fe(CN)6]4− with the underlying electrode. However, a pH-dependent redox compound, 4,4′-biphenyldiol (1) in solution, was permeable into the monolayer and gave well-defined cyclic voltammograms at both higher and lower pHs. Using this chemical-recognition ability of the modified electrode together with the formal potential shift of 1 according to the Nernst equation, pH–modulated vectorial electron transfer reactions were examined. At pH 3, cyclic voltammograms at the modified electrode in a 1 + [Fe(CN)6]4− aqueous solution revealed that one-way electron flow from [Fe(CN)]4− to the electrode via1 (oxidized form) occurred. On the contrary, at higher pHs (pH 9—11), the vectorial electron flow at the electrode in 1 + [Fe(CN)6]3− solution was reversed. A triggered change (‘switching’) between the anodic and cathodic vectorial electron transfer reactions by changing the pH was also possible at the C12SH-modified electrode in the presence of 1, [Fe(CN)6]4− and [Fe(CN)6]3− in solution. This finding may offer possibilities for the construction of functional molecular devices based on the tuning of rectified electron transfer reactions.
Order–Disorder Transition in a Dioctadecyldimethylammonium Chloride LB Film Studied by FT-IR ATR Spectroscopy
Authors: Kawai Takeshi
Published: June 2006

An order–disorder process in Langmuir–Blodgett (LB) films of dioctadecyldimethylammonium chloride (DODAC) has been studied by FT-IR ATR spectroscopy. This order–disorder process gradually occurred over a wide temperature range, and the transition was shifted to a higher temperature with the number of monolayers. In DODAC LB films immersed in water a similar thermotropic phase behavior was observed, except for the transition temperature. However, this behavior completely differed from that of cast film.
Comparative Ab initio and Hybrid DFT Studies Relevant to an Experimental Investigation of Neutral and Cationic [Si, P, H2] Isomers
Authors: Hrušák Jan , Schröder Detlef , Schwarz Helmut , Iwata Suehiro
Published: June 2006

The neutral and the lowest cationic (singlet and triplet) potential-energy surfaces of [Si, P, H2] have been explored by means of ab initio MO calculations at the G2 level of theory as well as the hybrid DFT (B3LYP/6-311G**) method. Contrary to the neutral and triplet surfaces, where the H2SiP+/0 isomers represent the global minima, for the singlet cation a doubly bridged P(H)2Si+ structure has been identified as the most stable isomer, with the non-bridged H2SiP+ species being significantly less stable (ΔE = 31.7 kcal mol−1 at G2). As far as the comparison of the two quantum-chemical methods (i.e. G2 and B3LYP) is concerned, the calculated relative energies ΔE are quite close to each other, with deviations smaller than 4 kcal mol−1. However, while the non-bridged SiPH2+ (1A′) represents a minimum at the G2 level, it could not be located using the hybrid DFT method. The computationally predicted singlet and triplet [Si, P, H2]+ potential-energy surfaces provide insight into the course of the ion/molecule reactions of Si+• with phosphine and P+ with silane, respectively, which were examined experimentally. Thus, the reaction of the doublet species Si+• with phosphine allows access to the non-classical, bridged P(H)2Si+ structure, while in the reaction of the P+ triplet cation with silane, no evidence for Si–P bond formation is obtained.
Preparation, Characterization, and Solid State Thermal Studies of Nickel(II) Squarate Complexes of 1,2-Ethanediamine and Its Derivatives
Authors: Das Debasis , Ghosh Ashutosh , Ray Chaudhuri Nirmalendu
Published: June 2006

[NiL3]C4O4 [L = 1,2-ethanediamine (en) and 1,2-N,N′-dimethylethanediamine (N,N′-dmen)], [NiL3]C4O4·nH2O [for L = 1,2-N-methylethanediamine (meen) and 2-methyl-1,2-propanediamine (ibn); n = 1, and for L = 1,2-propanediamine (pn); n = 2], and [NiL2C4O4]·2H2O [L = 1,2-N-ethylethanediamine (eten), 1,2-N-propylethanediamine (pren), 1,2-N,N-dimethylethanediamine (N,N-dmen) and 1,2-N,N′-diethylethanediamine (N,N′-deten)] have been synthesized by the addition of the respective diamines to finely powdered nickel(II)squarate dihydrate, NiC4O4·2H2O. All of the tris-species, except for [Ni(N,N′-dmen)3]C4O4 were also prepared by adding diamines to NiC4O4·2H2O dissolved in aqueous ammonia (25%). When the latter method was followed, the bis-species [NiL2C4O4] [L = eten, pren, 1,2-N-isopropylethanediamine (ipren), N,N-dmen, N,N′-dmen, and N,N′-deten] were also obtained. [NiL2C4O4] (L = en, meen, N,N′-dmen, pn, and ibn) were also prepared from their corresponding tris(diamine) species upon heating in the solid state. [Ni(ibn)3]C4O4·nH2O after dehydration underwent an irreversible endothermic (145—160 °C; ΔH = 6.5 kJ mol−1) phase transition without showing any visual color change. [Ni(ipren)2C4O4] exhibited a reversible phase transition (78—107 °C; ΔH = 1.4 kJ mol−1 for heating and 105—72°C; ΔH = −1.3 kJ mol−1 for cooling). The phase transitions are considered to have been due to conformational changes of the diamine chelate rings. All of the tris as well as bis(diamine) complexes possess an octahedral geometry, except for [Ni(ibn)2]C4O4, which is square-planar. The bis-species [NiL2C4O4] (L = eten, pren, N,N-dmen, and N,N′-deten) exists in two isomeric forms.
Sensing of Poly(styrenesulfonate)s by Polymeric Membrane Electrodes Based on Liquid Anion-Exchangers
Authors: Ohki Akira , Tsurugasaki Masato , Kondo Yasunori , Naka Kensuke , Maeda Shigeru
Published: June 2006

The potentiometric responses of ion-selective electrodes (ISEs) based on various liquid anion-exchangers for poly(styrenesulfonate)s (PSSs) were examined. The liquid anion-exchangers included lipophilic monoammonium, monophosphonium, diphosphonium, and triphosphonium salts. The molecular weights of PSSs, which had narrow molecular-weight distributions (Mw/Mn < 1.2), were varied from 1.8 × 103 (PSS-1.8K) to 3.5 × 104 (PSS-35K). For PSS-1.8K, ISEs based on diphosphonium salts, polymethylenebis(trioctylphosphonium) dibromides 1—3, exhibited good responses, the response slope and linear response range being −20 to −21 mV/decade and 5.0 × 10−5—5.0 × 10−3equiv dm−3, respectively. As the molecular weight of PSS was increased, the linear response range became smaller, while the response slope was almost constant. Finally, PSS-35K gave almost no response. On the other hand, a wide molecular-weight distribution PSS (Mw/Mn = 3.6) provided a good response, although it had a high average molecular weight (Mw = 1.6 × 104). The selectivity coefficients for PSS over various anions of ISEs, based on diphosphonium and monophosphonium salts, were assessed.
Complex Formation between Tributyl Phosphate and Nitric Acid and the Hydration of the Complexes in Dodecane
Authors: Naganawa Hirochika , Tachimori Shoichi
Published: June 2006

Complex-formation of nitric acid with tributyl phosphate (TBP) and the hydration of the complexes in dodecane were examined from the acid and water distribution data between the aqueous and organic phases at 298 K. The equilibrium constants were determined by analyzing the acid and water distribution data as functions of the TBP concentration in the organic phase, the aqueous acid activity, and the water activity. Three complexes (TBP·HNO3, (TBP)2·HNO3, and (TBP)3·HNO3) were found in the organic phase when the aqueous nitric acid concentration was not higher than 3 mol dm−3. The hydration numbers for these complexes were also obtained. The TBP·HNO3 was chiefly anhydrous, but partially a monohydrate. In contrast, the (TBP)2·HNO3 was only a monohydrate and (TBP)3·HNO3 was only a tetrahydrate. The TBP–HNO3–H2O stoichiometry, by taking account of these complexes in addition to the TBP hydrates and free nitric acid in the organic phase, applied very well, up to 2 mol dm−3 (54.6 vol%) TBP in dodecane without any activity correction.
Structures of Bis(5,5-diphenylhydantoinato)copper(II) Complexes with Primary Amines Involving Square Pyramidal CuN4O Chromophores
Authors: Akitsu Takashiro , Komorita Seiko , Kushi Yoshihiko , Li Chunmin , Kanehisa Nobuko , Kai Yasushi
Published: June 2006

Copper(II) complexes [CuL2(i-PrNH2)2·H2O] (1a), [CuL2(i-PrNH2)2] (1b), [CuL2(EtNH2)2·H2O] (2a), [CuL2(EtNH2)2]·CHCl3 (2b), [CuL2(EtNH2)2·H2O]·2CHCl3 (2c), and [CuL2(EtNH2)2·MeOH] (2d) (L = 5,5-diphenylhydantoinate) have been prepared. The crystal structures of 1a, 2c, and 2d were determined by X-ray analysis. Each CuN4O chromophore is a five-coordinated square-based pyramidal geometry. The axial Cu–O distances are Cu(1)–O(1)(water) = 2.362(10) Å, Cu(1)–O(1)(water) = 2.436(9) Å and Cu(1)–O(1)(MeOH) = 2.33(1) Å, for complexes 1a, 2c, and 2d, respectively. Intramolecular hydrogen bonds are formed between the carbonyl oxygens and amino hydrogens (C=O···H–N) as well as the axial ligand (C=O···H–O). The latter hydrogen bonds stabilize the axial ligand for coordination. Moreover, double intermolecular hydrogen bonds link the 5,5-diphenylhydantoinate ligands (C=O···H–N) belonging to be adjacent complex molecules in all three complexes. The electronic spectra of the complexes in the solid state and in chloroform solutions were determined at room temperature, and a considerable change in ligand field bands was observed. The five-coordinated complexes in the chloroform solutions release their axial water ligand and the CuN4O chromophore converts into a distorted tetrahedral CuN4 chromophore.
Electrocatalytic Hydrogenation of Organic Compounds on a Poly[N-(5-hydroxypentyl)pyrrole] Film-Coated Electrode Incorporating Palladium Microparticles
Authors: Takano Nobuhiro , Nakade Akihito , Takeno Noboru
Published: June 2006

A poly[N-(5-hydroxypentyl)pyrrole] film-coated carbon-fiber electrode incorporating palladium metal microparticles was prepared and the catalytic ability in the electrochemical hydrogenation of organic compounds was investigated. This electrode exhibited a high catalytic ability and a strong physical stability with respect to hydrogen evolution. By using this electrode, the electrocatalytic hydrogenation for organic compounds in an organic solvent–buffer solution led to an efficient formation of hydrogenated products, such as saturated compounds, amino compounds, and hydroxy compounds, in high yields and current efficiencies. Furthermore, a catalytic polymer film electrode was successfully applied to the hydrogenative deprotection of a benzyl group and the dehalogenation of bromobenzene in electroreduction media.
Conformation of Gramicidin in Monolayers, Organic Solvents and Phospholipid Bilayers
Authors: Ogoshi Satori , Mita Tomoyoshi
Published: June 2006

The properties of gramicidin and its action on membranes were investigated by the use of monolayers, organic solvents and phospholipid vesicles in relation to cation-binding. The behavior of a gramicidin monolayer was strongly dependent on the organic solvent in which it was dissolved, showing the dependence of the solvent history. A gramicidin monolayer prepared from an ethanol solution caused a large conformational change upon the binding of K+, whereas that prepared from a 2,2,2-trifluoroethanol (TFE) solution showed no conformational change upon the binding of K+. In two organic solvents, gramicidin showed a different calorimetric behavior, due to a difference in conformation. Gramicidin in ethanol markedly decreased the phase-transition temperature and transition enthalpy (ΔH) upon the binding of K+, whereas gramicidin in TFE did not change in calorimetric behavior upon the binding of K+. Incorporating gramicidin into lipid bilayers led to a broadening of the transition and a decrease in the ΔH of the lipid, showing that about 20 lipid molecules per gramicidin molecule were immobilized. By binding K+ to the gramicidin channel, the perturbing effect of gramicidin for the lipid bilayers was depressed, implying aggregation among the peptide channels.
A Novel Method for Constructing β-d-Mannosidic, 2-Acetamido-2-deoxy-β-d-mannosidic, and 2-Deoxy-d-arabino-hexopyranosidic Units from the Bis(triflate) Derivative of β-d-Galactoside
Authors: Sato Ken-ichi , Yoshitomo Akira , Takai Yoshimitsu
Published: June 2006

An efficient construction of the β-d-mannosidic, 2-Acetamido-2-deoxy-β-d-mannosidic, 2-deoxy-2-fluoro-β-d-mannosidic, and 2-deoxy-β-d-arabino-hexopyranosidic units from the same intermediate, 2-4-bis(O-trifluoromethylsulfonyl) derivative of β-d-galactoside, was achieved in good yields in a stepwise inversion at C-4 and C-2 by using cesium acetate, n-Bu4NN3, n-Bu4NF, and n-Bu4NBH4. A convenient and practical protection of β-d-mannoside to the straightforward synthesis of antennary oligosaccharides was also achieved by using cesium trifluoroacetate.
Practical Synthesis of Optically Pure Bifunctionalized Heterohelicenes
Authors: Osuga Hideji , Suzuki Hitomi , Tanaka Kazuhiko
Published: June 2006

Optically active 2-(hydroxymethyl)- and 2-(ethylthiocarbonyl)[1]benzothieno[5′,4′ : 2,3][1]benzothieno [4′,5 : 4,5]thieno[3,2-f]quinolines containing π-excessive thiophene and π-deficient pyridine units were prepared by the use of exo-3-amino-2-hydroxybornane as a chiral auxiliary. This procedure consists of separation of the helical diastereomers prepared by photocyclization of 1,2-diarylethylenes and removal of the chiral auxiliary by a thiolate ion. Large scale preparation of the helicenes can be accomplished by a modified procedure of the photocyclization reaction. Optical purities of both enantiomers of 2-(hydroxymethyl)- and 2-(ethylthiocarbonyl)[1]benzothieno[5′,4′ : 2,3][1]benzothieno[4′,5′ : 4,5]thieno[3,2-f]quinolines were >99.5%. Their absolute configurations were determined by comparison of CD spectra.
Comparison of the Reactivities of Neutral and Cationic Organopalladium Complexes toward CO, Isocyanides, and Olefins
Authors: Kayaki Yoshihito , Shimizu Isao , Yamamoto Akio
Published: June 2006

Cationic solvent-coordinated organopalladium complexes [PdR(solvent)(L)2]+A−  2 (R = organic group, L = tertiary phosphine, A = counter anion such as BF4, PF6, and triflate) have been prepared by removal of the halide ligand X in neutral complexes, [PdR(X)(L)2] 1 with an equimolar amount of silver salt. The cationic complexes 2 show much greater rates of CO insertion than the parent neutral complexes 1. Comparison of the reactivities of 2 and of the other cationic complexes [PdMe(Y)(L)2]+ (Y = strongly coordinating ligand such as tertiary phosphine, pyridine, and isocyanide) toward CO insertion indicates that availability of the site for incoming CO is a dominant factor in determining their reactivities. In contrast, insertion of isocyanides into Pd–C bond is not hindered by occupation of the vacant site in the organopalladium complexes. Successive hetero-insertions of isocyanide and CO into Me–Pd bond, i.e., CO insertion into the 1-iminoalkyl–Pd bond and isocyanide insertion into the acetyl–Pd, were realized. Olefins were found not to undergo the insertion into Pd–Me bond in phosphine-coordinated complexes, whereas insertion of methyl acrylate into the Me–Pd bond in a cationic complex having bipyridine ligand was observed.
Electron-Transfer Reactions in Organic Chemistry
Authors: Formosinho Sebastião J , Arnaut Luís G
Published: June 2006

The Intersecting-State Model (ISM) is used to calculated the absolute rate constants of self-exchange electron-transfer reactions (ET) of organic species. The systems studied include aromatic hydrocarbons, quinones, nitrobenzene, aromatic nitriles, tetracyanoethylene, aromatic amines, and alkylhydrazines. All of the calculated rates are within one order of magnitude of the experimental ones, and the correlation coefficient between the two sets is 0.96. An electron-tunneling model has been developed to calculate distance-dependent nonadiabatic factors of intramolecular ET. This model can be used with ISM to calculate intramolecular ET rates. The system biphenylyl-spacer-naphthyl in tetrahydrofuran, whose distance-dependent intramolecular rates were measured by Closs and Miller, was used to test our calculations, because its ET rates can be calculated without adjustable parameters. Our absolute rate calculations are in an order-of-magnitude agreement with the experimental ones.
Density and Volumetric Behavior of 1,2-Dimethoxyethane + Water Binary Mixtures from −10 to 80 °C
Authors: Marchetti Andrea , Tassi Lorenzo , Ulrici Alessandro
Published: June 2006

The densities (ρ) and excess molar volumes (VE) for 1,2-dimethoxyethane + water binary mixtures were determined, when possible, at 19 different temperatures ranging from −10 up to +80 °C. The experimental measurements were used to test some empirical relations giving the dependence of the density on the temperature and binary composition: ρ = ρ(t), ρ = ρ(X1), and ρ = ρ(t,X1). Furthermore, the results of VE calculations are discussed in terms of the influence of interactions between the components, of the order and degree of packing in the mixtures, and of the free-volume differences.
Synthesis and Catalytic Properties of Vanadium Nitrides
Authors: Choi Jeong-Gil , Jung Moon-Ki , Choi Saemin , Park Tae-Keun , Kuk Il Hiun , Yoo Jae Hyung , Park Hyun Soo , Lee Han-Soo , Ahn Do-Hee , Chung Hongsuk
Published: June 2006

Vanadium nitride catalysts were synthesized by the temperature-programmed reduction of vanadium oxide (V2O5) with pure NH3. The resulting materials contained VN or VN with a negligible amount of vanadium sesquioxide (V2O3) in the bulk after the nitrization of V oxides, indicating that the structural properties of these materials were strong functions of the heating rate and space velocity employed. The V nitrides proved to be active NH3 decomposition catalysts. Since the activity varied with changes in the surface area and particle size, ammonia decomposition over the V nitrides appeared to be structure-sensitive. While detailed relationships between the catalytic activity and surface composition could not be ascertained, there was a direct correlation between the activity, and the surface area and grain-boundary length. The most active catalyst, VN-c, which contained the δ-phase, had the greatest grain-boundary length. The catalytic properties of V nitrides were comparable or superior to those of a Ni/SiO2·Al2O3 catalyst. These results suggested that the characteristics of the active sites in the vanadium nitrides were similar to those in the Group 8—10 metal-based catalysts.
Ordering the Isomeric Molecules through the Graph Spectrum: Generation of Two Topological Indices Depicting the Branch and Linear Characters (A Computational Method)
Authors: Patra Swarna M , Mishra Rama K
Published: June 2006

Octane isomeric molecules have been ordered by using the graph spectrum of the vertex adjacency matrix and a Fortran-77 program. The program not only orders the isomeric molecules into various subgroups, but also generates topological descriptors, which primarily depict the branching and linear characters of the molecule. These descriptors are correlated with different physical properties, like standard entropy (), standard entropy of formation (), heat of vaporization (Hv), octane number (MON), and A coefficient of Antoine equation. Good correlations of the descriptors with the above properties have been obtained.
Markets: The Fulton Fish Market
Authors: Graddy Kathryn
Published: June 2006

The Fulton Fish Market was a colorful part of the New York City landscape that operated on Fulton Street in Manhattan for over 150 years. In 2005 the market moved from the South Street Seaport in lower Manhattan to Hunts Point in the South Bronx. The Fulton Fish Market—now called The New Fulton Fish Market—is one of the world's largest fish markets, second in size only to Tsukiji, the famous fish market in Tokyo. To economists, it may seem that a large centralized market with well-informed buyers and sellers should also be a very competitive market. But fish is a highly differentiated product. Buyers often wish to examine fish themselves, or have their agents do so. The centralized market performs an important function in matching fish to buyers. The high level of product differentiation and the institutional structure in the Fulton fish market can lead to patterns of behavior that suggest imperfect competition and a segmented market. At times in the past, the repeated nature of price setting and extensive knowledge of the sellers may have created the basis for tacit collusion and allowed the dealers to gather economic rents by exploiting the different elasticities and buying patterns. Additional economic rents resulted from subsidies. Before reforms in 1995, lax regulation of the market provided fertile ground for organized crime.
Why Europe and the West? Why Not China?
Authors: Landes David S
Published: June 2006

In the history of technological development, why didn't other regions keep up with Europe? This is an important question, as one learns almost as much from failure as from success. The one civilization that was in a position to match and even anticipate the European achievement was China. China had two chances: first, to generate a continuing, self-sustaining process of scientific and technological advance on the basis of its indigenous traditions and achievements; and second, to learn from European science and technology once the foreign “barbarians” entered the Chinese domain in the sixteenth century. China failed both times. What explains the first failure? I stress the role of the market: the fact that enterprise was free in Europe while China lacked a free market and institutionalized property rights; that in Europe innovation worked and paid, while the Chinese state was always stepping in to interfere with private enterprise. As for the second failure, China's cultural triumphalism combined with petty downward tyranny made it a singularly bad learner.
The Role of Family in Family Firms
Authors: Bertrand Marianne , Schoar Antoinette
Published: June 2006

History is replete with examples of spectacular ascents of family businesses. Yet there are also numerous accounts of family businesses brought down by bitter feuds among family members, disappointed expectations between generations, and tragic sagas of later generations unable to manage their wealth. A large fraction of businesses throughout the world are organized around families. Why are family firms so prevalent? What are the implications of family control for the governance, financing and overall performance of these businesses?
Boyfriends, Girlfriends and Teenagers' Risk of Sexual Involvement
Authors: Marín Barbara VanOss , Kirby Douglas B. , Hudes Esther S. , Coyle Karin K. , Gómez Cynthia A.
Published: June 2006

CONTEXT: Having a boyfriend or girlfriend, especially an older one, is associated with increased sexual risk in early adolescence. The mechanisms underlying this association are unclear.

METHODS: Middle school students in Northern California were surveyed annually from 1997 to 2000. For a sample of 1,214 males and 1,308 females who were sexually inexperienced in seventh grade, logistic and linear regression were used to explore associations between relationship status in seventh grade and sexual activity in ninth grade, controlling for sixth‐grade and eighth‐grade characteristics.

RESULTS: Males who had had a girlfriend their age by seventh grade were more likely than those who had had no relationship to report sexual activity in ninth grade (odds ratio, 2.1). Similarly, for females, the odds of being sexually active in ninth grade were elevated among those who had had a boyfriend their age (2.9); however, they also were higher among those who had had an older boyfriend than among those who had had one their age (2.1). With sixth‐grade risk factors controlled, relationship status in seventh grade remained significant only for females; the association was explained by early menarche and by participation in situations that could lead to sex and riskier peer norms in eighth grade. For males, eighth‐grade situations that could lead to sex, Hispanic ethnicity and sixth‐grade peer norms explained ninth‐grade sexual behavior.

CONCLUSIONS: To reduce the risk of adolescent sexual activity, parents and communities should encourage youth in middle school, especially females who experience early menarche, to delay serious romantic relationships.
Greater Expectations: Adolescents' Positive Motivations for Sex
Authors: Ott Mary A. , Millstein Susan G. , Ofner Susan , Halpern‐Felsher Bonnie L.
Published: June 2006

CONTEXT: Effective STD and pregnancy prevention efforts should benefit from knowledge of what motivates adolescents to have sex. Positive motivations, and how they differ by gender and sexual experience, are poorly understood.

METHODS: A sample of 637 ninth graders were asked about their relationship goals, expectations of the degree to which sex would satisfy these goals and sexual experience. Three scales measured adolescents' goals for intimacy, sexual pleasure and social status within a romantic relationship. Another three scales measured expectations that sex would lead to these goals. Data were examined in analyses of variance and mixed models.

RESULTS: Participants valued intimacy the most, then social status and, finally, sexual pleasure. These relationship goals differed significantly by gender and sexual experience. Females valued intimacy significantly more and sexual pleasure less than males. Sexually experienced adolescents valued both intimacy and pleasure more than sexually inexperienced adolescents. Among females, but not males, sexually experienced adolescents valued the goal of social status less than those with no sexual experience did. Adolescents expected that sex would most likely lead to sexual pleasure, then intimacy and, finally, social status. Females and sexually inexperienced adolescents reported lower expectations that sex would meet goals than did males and sexually experienced participants.

CONCLUSIONS: Adolescents view intimacy, sexual pleasure and social status as important goals in a relationship. Many have strong positive expectations that sex would satisfy these goals. Prevention programs and providers should address the risks of sex in the context of expected benefits.
Early Adolescents' Cognitive Susceptibility To Initiating Sexual Intercourse
Authors: L'Engle Kelly Ladin , Jackson Christine , Brown Jane D.
Published: June 2006

CONTEXT: Better methods for investigating sexual risk before the initiation of sexual intercourse are needed to support programming for younger adolescents, especially for abstinent adolescents who are susceptible to initiating intercourse.

METHODS: A sample of 854 adolescents in seventh or eighth grade who had never had sexual intercourse completed sexuality surveys in 2002 and 2004. A five‐item index that assessed beliefs and expectations about the onset of intercourse was created to indicate adolescents' cognitive susceptibility to initiating intercourse. Logistic regression analysis was used to assess associations between levels of susceptibility and initiation of intercourse by follow‐up. The construct and predictive validity of the index were examined using a variety of tests.

RESULTS: Thirty‐eight percent of respondents were classified as being nonsusceptible to initiating intercourse, 34% as having low susceptibility and 28% as being highly susceptible. Adolescents who were susceptible were more physically mature, had greater sexual feelings and competency, perceived that more peers were sexually active and had fewer positive connections with parents, school and religion than nonsusceptible respondents. Males, blacks and older adolescents were more susceptible than females, whites and younger adolescents, respectively. Compared with nonsusceptible respondents, those with low and high susceptibility had higher odds of initiating intercourse two years later (odds ratios, 2.5 and 8.1, respectively).

CONCLUSIONS: The cognitive susceptibility index provides a valid method for assessing sexual risk before the onset of intercourse. Assessing susceptibility among early adolescents could support efforts to delay the onset of intercourse through targeted research and health programming.
Dual Distribution and Intangible Firm Value: Franchising in Restaurant Chains
Authors: Srinivasan Raji
Published: June 2006

Dual distribution systems in which firms use vertical integration and market governance simultaneously are widely used across diverse marketing contexts (e.g., restaurants, retailing, industrial selling). A prominent example of dual distribution includes business format franchising, in which firms (i.e., the franchisors) license the operation of some of their units to franchisees while owning and operating some units themselves. Despite the widespread prevalence of dual distribution, there are few insights into its performance implications. In this article, the author examines the relationship between a firm's dual distribution strategy and its intangible value. Franchising in restaurant chains serves as the empirical context for the study. It is proposed that a firm's dual distribution strategy affects its intangible value both independently and jointly with a set of firm characteristics. The author considers the firm's age, scope of vertical integration, advertising, financial leverage, and financial liquidity as firm characteristics that influence the relationship between dual distribution strategy and intangible value. The author measures the firm's dual distribution strategy by the proportion of its franchised units to its total units and intangible value by its Tobin's q. The author estimates the proposed model using panel data on 55 publicly listed U.S. restaurant chains for the period 1992–2002. Unobserved firm heterogeneity is accommodated using latent class regression analysis. The results support a four-segment model. Dual distribution increases intangible value for some firms but decreases intangible value for others, both independently and in conjunction with other firm characteristics.
Comparability of indices for insulin resistance and insulin secretion determined during oral glucose tolerance tests
Authors: Haeckel Rainer , Raber Rüdiger , Wosniok Werner
Published: June 2006

Clin Chem Lab Med 2006;44:817–23.
Abortions – History and Facts
Authors: Pinto Maria Cristina Rosamond
Published: June 2006

Since ancient times gestation has been part of a woman's role starting from her very existence. To give birth is no doubt an universal experience and although this experience may be the cause of death of the mother, the child or both, all the Treaties of Medicine (Ancient, Middle Age, Renaissance, Islam and Modern days) have devoted special attention to such an important event in a woman's life. Starting with the ancient culture, the assistance to the birth of a child (banned to men in the Christian or Arab world) has been endorsed to the hands of women nominated as “mid-wives” or “matrons”; it is only by the end of the XVIII century that physicians begin to act, and, starting from then, the obstetrics practice is promoted in various Universities. Practices connected with the birth or abortions were only of public knowledge long after they were used, through various manuscripts and documents. Even the finding of pregnant women with newborns buried next to them does not prove that difficult deliveries were not in the basis of these findings. Regarding the scientific philosophers little is known viewing the field of obstetrics. The IX and VIII centuries (BC) were followed by the pre-Hippocratic philosophers of the VI century. These philosophers created medical schools, masters in medicine and practicing students, but they were not really concerned about sexual problems – gestation, deliveries, abortion, etc.
The Supreme Court's Merck KGaA v. Integra Lifesciences I, LTD. Opinion extends the Exemption from Infringement under Section 271(e)(1) to Biotechnology “Research Tools”
Authors: Olson Bradley J
Published: June 2006

The exemption from patent infringement under 35 U.S.C. § 271(e)(1) was significantly extended by the Supreme Court in
Informed Consent and Psychotherapy: The Travails of Consistency (Part I)
Authors: Choong Kartina A
Published: June 2006

The ascendancy of psychological therapy over the last few decades has been phenomenal. During this period, the health care scene has witnessed the continuous proliferation of distinct therapeutic modalities and a marked increase in the demand for psychotherapeutic services. In response, there is now a growing concern as to whether clients who enter therapy do so on an adequately informed basis both as to the range of treatment on offer and what they entail. One movement in this direction has been to call for the adoption of the doctrine of informed consent in this realm. This paper questions the viability of this move. By retracing the doctrine's development to its conception at the dawn of the twentieth century, it will be shown that although the law has undergone three major changes since then, the ‘patient's right to self-determination’ remains the one consistent feature that runs through the doctrine's history and that now, as then, this principle relates primarily to the patient's interest in his bodily integrity. This paper argues that not only are the factors which gave rise to the notion of informed consent peculiar to the medical model, but since psychotherapy does not characteristically involve physical contact, the current law's consequent emphasis on risks-disclosure and freedom from unauthorized bodily intrusions are also generally incompatible with the ethos and reality of psychotherapeutic practice.
Incomplete fusion mechanism in 16O + 93Nb reaction at 6 MeV/nucleon: Recoil range measurements
Authors: Mukherjee S. , Sharma Anil , Goswami A. , Tomar B. S.
Published: June 2006

Recoil range distribution of evaporation residues formed in complete and incomplete fusion of 96 MeV 16O with 93Nb has been measured by recoil catcher technique followed by off-line gamma-ray spectrometry. The cross sections for complete and incomplete fusion were delineated from the earlier measured excitation function data at the same beam energy. The results show that incomplete fusion is associated with angular momentum values close to the critical angular momentum for complete fusion of the projectile and target.
Solvent extraction behaviour of some fission product elements withN,N-dihexyl octanamide and tri-n-butyl phosphate under simulated PUREX process conditions
Authors: Kulkarni P. G. , Gupta K. K. , Gurba P. B. , Janardan P. , Changrani R. D. , Dey P. K. , Manchanda V. K.
Published: June 2006

Extraction behaviour of some fission product contaminants like Zr(IV), RuNO(III), La(III), Ce(III) and Nd(III) with 1.1 M solutions ofN,N-dihexyl octanamide (DHOA) and tri-n-butyl phosphate (TBP) inn-dodecane from nitric acid medium has been investigated under conditions prevailing in the PUREX process. Results of the study reveal that the extraction of Zr(IV), La(III), Ce(III) and Nd(III) with 1.1 M DHOA is significantly lower than that of TBP. However, the extraction of RuNO(III) with DHOA is of the same order as that with TBP. The influence of uranium(VI) saturation of the organic phase on the extraction of Zr(IV) and RuNO(III) is evaluated. The effect of degradation products of DHOA (caprylic acid/n-dihexylamine) and TBP (di-n-butyl phosphoric acid) on the extraction of Zr(IV) is also examined. The study indicates the innocuous nature of the degradation products of DHOA towards the extraction of Zr(IV) under the PUREX process conditions. This is unlike the degradation products of TBP, the presence of which produce noticeable increase in the extraction of Zr(IV).
Transport of uranium from nitric acid solution by non-dispersive solvent extraction using a hollow fibre contactor
Authors: Patil C. B. , Mohapatra P. K. , Singh R. R. , Gurba P. B. , Janardan P. , Changrani R. D. , Manchanda V. K.
Published: June 2006

Membrane based non-dispersive solvent extraction (NDSX) of U(VI) from aqueous nitric acid medium was carried out using a commercial hollow fibre module containing microporous hydrophobic polypropylene capillaries. The NDSX operation was carried out by pumping U(VI) solutions at varying concentrations of nitric acid (1-5 M) through the tube side and organic solvent (di-n-hexyl octanamide (DHOA) in normal paraffin hydrocarbon (NPH)) through the shell side of the hollow fibre capillaries. Extraction studies were performed under different hydrodynamic conditions and the overall mass transfer was evaluated under counter-current flow conditions. Counter-current mode was found to be better as compared to the co-current mode. The U(VI) mass transfer rates were positively influenced by the nitric acid as well as DHOA concentrations.
Fixation of some major fission products in NaZr2P3O12 ceramic employing microwave heating
Authors: Naik A. H. , Thakkar N. V. , Palkar V. R. , Dharwadkar S. R. , Mudher K. D. Singh , Venugopal V.
Published: June 2006

Attempts were made to introduce four major fission products, namely, Cs, Sr, Ru and Te into thermodynamically stable NaZr2P3O12 (NZP) ceramic, considered to be a viable alternative for fixation of high level nuclear waste (HLW), in place of borosilicate glass. The results showed that all these elements could be incorporated in NZP at temperatures as low as 723 K by heating the reaction mixtures in a microwave heating system. Among the four elements introduced in NZP, except for Te, all others were retained nearly quantitatively in samples heated to 1273 K for three hours. The tellurium substituted NZP exhibited the maximum loss exceeding the amount of TeO2 added, which could probably be due to formation of some volatile compounds by TeO2 with the elements in the NZP matrix. Addition of Sr and Te simultaneously in NZP decreased the amount of TeO2 loss considerably.
Synthesis, characterization and structural refinement of polycrystalline uranium substituted zirconolite CaZr0.9U0.1Ti2O7
Authors: Shrivastava Omprakash , Kumar Narendra , Sharma I. B.
Published: June 2006

Ceramic precursors of Zirconolite (CaZrTi2O7) family have a remarkable property of substitution on Zr4+ cationic sites. This makes them a potential material for nuclear waste management in ‘synroc’ technology. In order to simulate the mechanism of partial substitution of zirconium by tetravalent actinides, a solid phase of composition CaZr0.9U0.1Ti2O7 was synthesized through ceramic route by taking calculated quantities of oxides of Ca, Ti and nitrates of uranium and zirconium, respectively. Solid-state synthesis was carried out by repeated pelletizing and sintering the finely powdered oxide mixture in a muffle furnace at 1050 °C. The polycrystalline solid phase was characterized by its typical powder diffraction pattern. Step analysis data were used for ab initio calculation of structural parameters. The SEM and EDAX analysis also confirm that the zirconolite acts as a host material for uranium. The powder diffraction data of 3500 points for 2θ=10°-80° has been analysed by GSAS (general structure analysis system) software to obtain the best fit of the observed data points. The uranium substituted zirconolite crystallizes in monoclinic symmetry with space group C2/c (#15). The following unit cell parameters have been calculated: a=12.5615(13), b=7.2743(8), c=11.5103(33) and β=101.086(14). The calculated and observed values of the intensities, lattice parameters and density measurement show good agreement. The Rietveld analysis and GSAS based calculations for bond distance Ti-O, Ca-O, Zr-O, and O-M-O bond angles were made. The structure was refined to satisfactory completion. The Rp and Rwp were found to be 0.1583 and 0.2097 respectively. The crystal data of the title compound show that increase in U content results in expansion of the zirconolite unit cell.
Effect of glass composition on diffusion of cesium in borosilicate glass
Authors: Kumar Sumit , Rawat Neetika , Bhattacharya A. , Tomar B. S. , Shrikhande V. K. , Kothiyal G. P.
Published: June 2006

Heavy ion Rutherford backscattering spectrometry, with 30 MeV 19F beam, has been used to study the diffusion of cesium in borosilicate glasses of different compositions. The coefficient of cesium diffusion in borosilicate glass was obtained by analyzing the depth profile of cesium in samples annealed at different temperatures in the range of 100-350 °C. The activation energy of diffusion of cesium was found to be in the range of 9-22 kJ/mol, indicating the inter-diffusion between the cesium and sodium as the mechanism of the diffusion process. The activation energy was found to decrease with increasing sodium content of the glass, indicating that the alkali metal ion diffusion is governed by the interaction between the jumping ion and the dipole field around the oxygen ions.