bluuebunny/crossref_metadata_2025_split huggingface dataset:
Volume Study on the Micelle Formation of Local Anesthetic Dibucaine Hydrochloride and Dodecyltrimethylammonium Chloride Mixtures
Authors: Yamanaka Michio , Matsuki Hitoshi , Kaneshina Shoji 
Published: July 2006

Abstract
Densities of aqueous solutions of mixtures of dibucaine hydrochloride (DCHC), a local anesthetic, and dodecyltrimethylammonium chloride (DTAC) were measured as functions of total molality. The apparent molar volumes of the mixtures were calculated from the density data. The molar volumes in the monomeric and micellar states were evaluated from the dependence of the apparent molar volume on the total molality. The critical micelle concentration (cmc) of the mixtures was determined from the break point of the apparent molar volume vs. the total molality curves, while the micellar composition was evaluated from the dependence of the cmc on the mole fraction of DTAC in the mixture. The composition diagram of micellization has a swollen cigar shape, slightly distorted in the composition range near the DTAC component; such a distortion indicates slightly non-ideal mixing between the hydrophobic groups of DCHC and DTAC molecules in the micelle. However, the molar volume of micellar state varies depending upon the micellar composition along a straight line connecting the molar volumes of DCHC and DTAC. Moreover, the volume of micelle formation is smaller for DCHC, which has larger monomer and micellar volumes than DTAC, and increases linearly with increasing DTAC composition in the micelle. Therefore, the bulky structure of the hydrophobic part of the DCHC molecule affects both the miscibility and the volume behavior in the DCHC–DTAC mixed micelles.
Kinetics of Polymerization of Acrylamide in Aerosol OT W/O Microemulsions
Authors: Kawai Takeshi , Yasuda Yoichi , Kon-no Kijiro 
Published: July 2006

Abstract
Time dependence of the conversion of acrylamide (AAm) initiated with potassium peroxodisulfate (KPS) was examined at various [AAm] and [KPS] in W/O microemulsions of 1,4-bis(2-ethylhexyl) sodium sulfobutanedioate in cyclohexane media at 45 °C. The rate of polymerization (Rp) calculated from the conversion-time profiles yielded the following equation: Rp ∝ [AAm]1.0[KPS]0.5. From these values of reaction orders for AAm and KPS, it was found that the polymerization of acrylamide in W/O microemulsions can be regarded as normal radical polymerization and biradical termination between polymer radicals.
Solubilization of Water-Insoluble Dyes by Polyion/Surfactant Complexes
Authors: Hayakawa Katumitu , Shinohara Satoshi , Sasawaki Shin-ichiro , Satake Iwao , Kwak Jan C T 
Published: July 2006

Abstract
Solubilization data for the water-insoluble dyes o-(2-amino-1-naphthylazo)toluene (OY) and 1-pyrenecarbaldehyde (PyA) in mixed solutions of anionic polyelectrolyte and a cationic surfactant are reported. The polymers used were sodium dextran sulfate (DxS) and the sodium salt of poly(styrenesulfonic acid) (PSS). The surfactants used were dodecyltrimethylammonium bromide (DTAB) and tetradecyltrimethylammonium bromide (TTAB). DxS exhibited a highly cooperative binding of the surfactant ions, while binding to PSS occured at lower surfactant concentrations, but was less cooperative. DxS/surfactant complexes had a larger solubilization capacity per bound surfactant ion for both OY and PyA than did PSS/surfactant complexes. The standard Gibbs energy changes for solubilization in DxS/DTAB were determined to be 4.0 kJ mol−1 for OY and 5.4 kJ mol−1 for PyA; the values in PSS/DTAB were 6.5 kJ mol−1 for OY and 9.3 kJ mol−1 for PyA. The solubilization capacities and standard Gibbs energy changes of polyion/surfactant complexes strongly relate to the binding mode of the surfactant. The differences in the solubilization capacities and standard Gibbs energy changes between polyion/surfactant complexes and DTAB or TTAB micelles, and between OY and PyA, are discussed in relation to the aggregate size and solubilizate location.
Ab initio Classical Trajectory Calculations: Application to Four-Centered HF Elimination from Vinyl Fluoride
Authors: Takayanagi Toshiyuki , Yokoyama Atsushi 
Published: July 2006

Abstract
Classical trajectories for four-centered HF elimination from vinyl fluoride have been calculated directly from ab initio molecular orbital results at the HF/3-21G level of theory, without the construction of an analytical potential energy function. The excess energy dependences of the product energy distributions and vector correlations were calculated. The calculated results were compared with available experimental data and qualitative agreements were obtained. However, in order to obtain quantitative agreements, trajectory analyses at a more accurate ab initio level of theory seem to be necessary.
Photochemistry of Cobalt(III) Complexes. II. Cobalt(III) Complex with a Co–C–S Three-Membered Ring Prepared by Photodecarboxylation of 2,2′-Thiodiacetato Complex. Crystal Structure of (−)537CD-fac-trans(NH,O)-[Co(CH2SCH2COO)(dien)]ClO4
Authors: Yonemura Toshiaki , Kawaguchi Hiroshi , Shibuya Kimi , Murakami Kaori , Ama Tomoharu , Yasui Takaji , Okamoto Ken-ichi , Hidaka Jinsai 
Published: July 2006

Abstract
The diethylenetriamine (dien) cobalt(III) complex with a three-membered ring, fac-trans(NH, O)-[Co(CH2SCH2COO)(dien)]+ (1), has been prepared in an aqueous solution by the photodecarboxylation of u-fac- (2) or s-fac-[Co(2,2′-thiodiacetato)(dien)]+ (3). Perchlorate salt of 1 was subject to spontaneous resolution, and the crystal structure and absolute configuration for the isomer were determined by X-ray diffraction. The crystal is monoclinic, space group P21, a = 6.962(1), b = 13.411(1), c = 7.663(1) Å, β = 101.921(8)°, V = 700.1(2) Å3, Z = 2, and R = 0.032. The formation of the three-membered ring introduces a significant distortion into the octahedral coordination around the Co atom (∠C–Co–S = 49.4(1)°), although the bond lengths in the ring are within the range normally observed for other complexes. For the isomer the chiral configuration is regulated to ΔΛΔ and R for the sulfur atom. The racemization rate of 1 is very fast in water and DMSO. The position of the first d–d band of 1 is red-shifted by 1600—1100 cm−1 relative to those of 2 and 3. The photolysis of mer-[Co(3,3′-thiodipropionato)(dien)]+ did not give a similar product to 1.
Skeletal Rearrangement of the Dehydroabietic Acid Derivative
Authors: Matsumoto Takashi , Takeda Yoshio , Soh Kimiko , Sakamoto Mitsuo , Imai Sachihiko 
Published: July 2006

Abstract
Methyl 7-oxo-5,8,11,13-abietatetraen-18-oate was reduced with sodium borohydride in the presence of cerium(III) chloride heptahydrate to give the corresponding 7-hydroxy compound, which was rearranged into methyl 7-isopropyl-1,10-dimethyl-1,2,3,4-tetrahydroanthracene-1-carboxylate (14) possessing a rearranged linear abietane skeleton, by a treatment with boron trifluoride etherate. The reduction of 14 with lithium aluminum hydride afforded 7-isopropyl-1,10-dimethyl-1,2,3,4-tetrahydroanthracene-1-methanol (15). This was further converted into 7-isopropyl-1,1,10-trimethyl-1,2,3,4-tetrahydroanthracene. The mesylate of 15 was also rearranged into 2-isopropyl-5,9-dimethyl-7,8-dihydro-6H-cyclohepta[b]naphthalene, possessing a seven-membered A ring.
Synthesis and Properties of α,ω-Disubstituted Oligo(3-hexylthiophene)s and Oligothienoquinonoids in Head-to-head Orientation
Authors: Higuchi Hiroyuki , Nakayama Taketoshi , Koyama Haruki , Ojima Juro , Wada Tatsuo , Sasabe Hiroyuki 
Published: July 2006

Abstract
The two types of highly-ordered oligo(3-hexylthiophene)s in head-to-head orientation, a series of α,ω-disubstituted oligothiophenes and a series of bis(dicyanomethylene)oligothienoquinonoids, were synthesized. The properties of these compounds are discussed on the basis of the electronic spectra and cyclic voltammetry.
Deposition of Copper Using Photoexcited Riboflavin
Authors: Morishita Shinya , Suzuki Ken-ichi 
Published: July 2006

Abstract
In the presence of riboflavin and ethylenediaminetetraacetic acid (EDTA), deposition of copper was observed upon irradiation. Selective deposition of copper onto irradiated parts of a riboflavin-adsorbed alumina substrate was accomplished in an electroless copper plating solution containing EDTA. Two lines per millimeter were written on the substrate. The peel adhesion strength of the plated copper layer was comparable to that of a copper layer plated by a conventional method.
Visible Light Induced Hydrogen Evolution on CdS/K4Nb6O17 Photocatalyst
Authors: Yoshimura Joji , Tanaka Akira , Kondo Junko N , Domen Kazunari 
Published: July 2006

Abstract
The photocatalytic ability of CdS/K4Nb6O17 photocatalyst for H2 evolution by visible light irradiation was studied in connection with its structure. CdS/K4Nb6O17 was prepared by cation exchange reaction of K+ to Cd2+ ions in aqueous Cd(NO3)2 solution, followed by sulfurization in aqueous Na2S solution. The catalyst obtained by this procedure showed much higher H2 evolution activity in aqueous K2SO3 solution under visible light irradiation (λ &gt; 420 nm) than a physical mixture of CdS and K4Nb6O17 powders. This result was interpreted as due to more intimate contact of CdS and K4Nb6O17 in CdS/K4Nb6O17 photocatalyst, which enabled the efficient transfer of excited electrons. The activity of the catalyst was greatly dependent on the sulfurization condition, with this optimum condition: at room temperature for one week. XRD, EXAFS, TEM, and UV-DRS showed that most CdS particles, ca. 10 nm in diameter, existed on the external surface of K4Nb6O17, while a small amount of CdS was inferred to be located at the interlayer space of K4Nb6O17 as ultra fine particles.
Atomic-Scale Surface Structures of TiO2(110) Determined by Scanning Tunneling Microscopy: A New Surface-Limited Phase of Titanium Oxide
Authors: Onishi Hiroshi , Fukui Ken-ichi , Iwasawa Yasuhiro 
Published: July 2006

Abstract
The structure transformation of a TiO2(110) surface was observed at atomic-scale resolution by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). Irregular corrugations on an argon-bombarded TiO2(110) surface crystallized to stacked (1 × 1) terraces by vacuum annealing at 600—800 K. The terraces grew in dimension to be as large as 30 × 30 nm2 at 900 K. The unoccupied surface states localized on individual Ti4+ ions were resolved on a (1 × 1) terrace. The position of the Ti4+ ions was probed by imaging adsorbed formate ions. Annealing at higher temperatures resulted in the formation of a wide row structure comprising double strands. Imaging of individual adsorbed formate ions was used to grade possible structure models by probing Ti ions exposed on the surface; thereby, an added Ti2O3 row model, which is a new surface-limited phase of titanium oxide consisting of Ti3+ ions of the optimum six-fold coordination, was concluded for the double-strand structure. These results demonstrate the ability of probing experiments with an adsorbed molecule to determine the chemical nature of imaged sites on multi-component materials by STM.
Quantum Reactive Scattering Calculation for Four-Atom Chemical Reaction Systems: Application of a Fixed-Angle Approximation
Authors: Takayanagi Toshiyuki 
Published: July 2006

Abstract
An approximate quantum mechanical method is described for calculating reaction probabilities for the general four-atom chemical reaction AB + CD → A + BCD. By applying a fixed-angle approximation, reaction probabilities are calculated for the H2 + CN → H + HCN reaction on a semiempirical potential energy surface. The calculated results are compared favorably with those of quasiclassical trajectory calculations.
Syntheses and Some Properties of S-Bridged Pentanuclear Co(III)–Hg(II) or Rh(III)–Hg(II) Complexes with 2-Aminoethanethiolate. Crystal Structures of [{Rh(aet)3}2(HgCl2)3] and [{Rh(aet)3}2Hg3(NO3)4](NO3)2
Authors: Okamoto Ken-ichi , Kageyama Yuichi , Konno Takumi 
Published: July 2006

Abstract
S-Bridged pentanuclear complexes [{Rh(aet)3}2(HgCl2)3] (1) and [{M(aet)3}2Hg3(NO3)4]2+ (M = Rh(III), 2 and Co(III), 3) were newly prepared by the reaction of fac(S)-[M(aet)3] with HgCl2 or Hg(NO3)2; where aet denotes 2-aminoethanethiolate. The crystal structures of 1 and 2 were determined by X-ray diffraction methods. These complexes consist of two fac(S)-[M(aet)3] subunits, three Hg atoms, six chlorides (for 1) or nitrates (for 2), and water molecules, in which the configuration of the five metals is an approximately regular trigonal-bipyramid. Each Hg atom in these complexes takes a highly distorted tetrahedral geometry. There are three kinds of nitrates in [{Rh(aet)3}2Hg3(NO3)4](NO3)2, bridged bidentate, monodentate, and anion. Both 1 and 2 possess a novel chirality due to the helical structures of three Rh–S–Hg–S–Rh chains. Although 1 was insoluble in water, 2 and 3 were optically resolved by fractional precipitation. These complexes were characterized by their absorption, CD, and NMR spectra. The coordinated nitrates in 2 and 3 were readily replaced by water molecules when dissolved in water. The stabilities of the S-bridged pentanuclear complexes are also discussed.
Electrogenerated Acid as an Efficient Catalyst for Alcoholyses and Hydrolyses of Epoxides
Authors: Safavi Afsaneh , Iranpoor Nasser , Fotuhi Lida 
Published: July 2006

Abstract
The electrochemical transformation of different epoxides to their corresponding β-alkoxy alcohols and diols was achieved by using an electrogenerated acid-catalyst. A competitive ring-opening reaction of activated epoxides in the presence of deactivated epoxides was also successfully carried out in both alcohols and water.
Rearrangement Approaches to Cyclic Skeletons. IX. Stereoselective Total Synthesis of (±)-Camphorenone Based on a Ring-Contraction of Bicyclo[3.2.1]oct-6-en-2-one. Reliable One-Step Diazo Transfer Followed by a Wolff Rearrangement
Authors: Uyehara Tadao , Takehara Naohiko , Ueno Masako , Sato Toshio 
Published: July 2006

Abstract
A direct diazo transfer reaction to bicyclo[3.2.1]oct-6-en-2-ones and related compounds was accomplished by treatments with 2,4,6-triisopropylbenzenesulfonyl azide and potassium t-butoxide at −78 °C in THF. A Wolff rearrangement of the resulting α-diazoketones in the presence of water gave ring-contraction products, bicyclo[2.2.1]heptenecarboxylic acids. Using these two transformations the total synthesis of (±)-camphorenone was achieved stereoselectively, starting from 1-methoxybicyclo[2.2.2]oct-5-en-2-one.
Preparation and Characterization of DNA–Lipoglutamate Complexes
Authors: Sato Toshinori , Kawakami Takashi , Shirakawa Nobuaki , Okahata Yoshio 
Published: July 2006

Abstract
We newly prepared DNA–lipoglutamate polyion complexes by mixing aqueous solutions of DNA and cationic lipoglutamates such as α,γ-dibutyl glutamate (2C4N+), α,γ-dihexyl glutamate (2C6N+), and α,γ-dioctyl glutamate (2C8N+). Formation of the DNA–lipoglutamate complex was confirmed by gel chromatography, elemental analysis, CD spectra, and light scattering measurement. Compaction of DNA by binding with the cationic lipoglutamate was revealed by multi-angle light scattering. The DNA–lipoglutamate complexes showed the high stability for enzymatic hydrolysis by DNase I, which was confirmed by a quartz-crystal microbalance (QCM) technique. The DNA–lipoglutamate complexes showed the strong interactions with the lipid membranes and tumor cells compared with native DNA.
Total Synthesis of dl-Ascofuranone and Related Compounds
Authors: Saimoto Hiroyuki , Ohrai Shin-ichiro , Sashiwa Hitoshi , Shigemasa Yoshihiro , Hiyama Tamejiro 
Published: July 2006

Abstract
Convergent synthesis of an antitumor protective agent, ascofuranone, was accomplished by (1) preparation of the terpenoid side chain having a furanone moiety, (2) coupling the side chain with a protected phenol derivative, and (3) deprotection to regenerate the hydroxyl groups. This strategy was successfully applied to the synthesis of oxidized and cyclized analogs of ascofuranone. Some of the ascofuranone derivatives were found to inhibit the growth of P388 leukemia cells.
Syntheses and Characterization of Cubane-Type Clusters with Molybdenum–Iron–Sulfur (Mo3FeS4) or Molybdenum–Nickel–Sulfur (Mo3NiS4) Cores. X-Ray Structures of [Mo3FeS4(H2O)10](CH3C6H4SO3)4·7H2O and [Mo3FeS4(H2O)(NH3)9]Cl4, and Discrete Variational (DV)-Xα Calculation of the Electronic Structures of [Mo3FeS4(H2O)10]4+, [Mo3FeS4(H2O)(NH3)9]4+, and [Mo3NiS4(H2O)10]4+
Authors: Shibahara Takashi , Sakane Genta , Naruse Yoshiyuki , Taya Kazuhisa , Akashi Haruo , Ichimura Akio , Adachi Hirohiko 
Published: July 2006

Abstract
Reaction of the incomplete cubane-type cluster [Mo3S4(H2O)9]4+ (A) with iron gives a novel cubane-type aqua cluster [Mo3FeS4(H2O)10](CH3C6H4SO3)4·7H2O (B′). An ammonia coordinated derivative cluster [Mo3FeS4(H2O)(NH3)9]Cl4 (C′) is also synthesized. X-ray structural analyses of B′ and C′ revealed that the clusters, [Mo3FeS4(H2O)10]4+ (B) and [Mo3FeS4(H2O)(NH3)9]4+ (C), have an approximate symmetry of C3v. The iron atom has fairly regular tetrahedral geometry in both clusters. The effective magnetic moments of B′ at 2.16 K and 269.95 K are 2.78 and 3.26 B.M., respectively. 57Fe-Mössbauer spectroscopy showed that the oxidation states of iron in B′ and C′ were assignable to be +2.39 and +2.54, respectively, which indicates that the reaction is a reductive addition of an iron atom to the Mo3S4 core in A. The cyclic voltammograms of A, B, and [Mo3NiS4(H2O)10]4+ (D) show three consecutive one electron reductive steps, respectively, and the oxidation states of metals in B and D are assigned as MoIVMoIII2MII (M = Fe, Ni). Discrete variational (DV)-Xα calculation of B, C, and D explains the magnetic behavior, XPS spectra, and reactivity toward CO, C2H2, and C2H4.
Photodissociation of CF2Br2 at 248 nm: A Time-Resolved Absorption Study
Authors: Vatsa Rajesh Kumar , Kumar Awadhesh , Naik Prakash Dattatray , Rama Rao Kuchimanchi Venkata Subba , Mittal Jai Pal 
Published: July 2006

Abstract
Photodissociation of CF2Br2 at 248 nm has been studied in the gas phase using time-resolved optical absorption spectroscopy. A transient absorption spectrum in the range of 200—320 nm with λmax ≈ 260 nm is observed and has been assigned to the primary photodissociation product, the CF2Br radical. The absorption cross section of this radical at 260 nm has been found to be (1.05 ± 0.2) × 10−18 cm2 molecule−1. The rate constant for CF2Br dimerization is evaluated to be (3.0 ± 0.6) × 10−12 cm3 molecule−1 s−1. Laser fluence dependence in the secondary photodissociation of CF2Br radical is discussed.
Silver Ion Selective Extraction with Dithiaza-, Tetrathiaza-, and Tetrathiadiazacrown Ether Derivatives
Authors: Sakamoto Hidefumi , Ishikawa Junichi , Otomo Makoto 
Published: July 2006

Abstract
Dithiazacrown, tetrathiazacrown, and two tetrathiadiazacrown ether derivatives, bearing a phenyl group on each nitrogen atom at the periphery, were synthesized, and the solvent extractions of some transition metal ions with these compounds were carried out using an H2O–1,2-dichloroethane system. All of the thiazacrown compounds employed exhibited Ag+ selectivity, and formed 1 : 1 : 1 complexes of Ag+ : ligand : laurate ion as a counter anion to be extracted into a 1,2-dichloroethane solution. The extractabilities (extraction constants, Kex) for Ag+ decreased in the order: 7,16-diphenyltetrathia-7,16-diaza-18-crown-6 (3) (log Kex = 1.18 ± 0.13) &gt; 13-phenyltetrathia-13-aza-15-crown-5 (2) (0.75 ± 0.09) &gt; 7-phenyldithia-7-aza-9-crown-3 (1) (−0.47 ± 0.06) &gt; 13,16-diphenyltetrathia-13,16-diaza-18-crown-6 (4) (−0.62 ± 0.16).
Enhanced Membrane-Perturbing Activities of Bundled Amphiphilic α-Helix Polypeptides on Interaction with Phospholipid Bilayer
Authors: Sakamoto Seiji , Mihara Hisakazu , Matsuo Eitarou , Niidome Takuro , Anzai Kazunori , Kirino Yutaka , Aoyagi Haruhiko 
Published: July 2006

Abstract
The 24-peptide 46, designed to take an amphiphilic α-helix structure, had strong activity toward phospholipid membranes and could form ion-channels selective for cations on a planar membrane [J. Biol. Chem., 266, 20218 (1991)]. Four, six, and eight segments of the peptide 46 were bundled (4α-46, 6α-46, and 8α-46) on dendrimers consisting of Lys residues. These bundled peptides had highly α-helical structures with an enhanced α-helicity compared with the original 46 peptide. These peptides had hydrophobic pockets inside the bundle structures in aqueous solution in which the fluorescent hydrophobic probe, 1-anilino-8-naphthalenesulfonate (ANS), bound strongly. The peptides caused much leakage of carboxyfluorescein from small unilamellar vesicles of phospholipids at much lower concentrations of peptides than 46 did. Furthermore, the peptides induced the vesicle fusion at lower concentrations than those of the leakage. Four segments of the analogous 24-peptide 46S, in which six Ser residues were introduced instead of Ala and Leu residues in 46, were bundled by the same method (4α-46S). The fluorescent properties of the Trp residues incorporated at the 1 and 12 positions in 4α-46S, respectively, indicated that the centers of the helices were in more hydrophobic conditions than the N-terminal was. These facts caused us to conclude that the bundled conformation increased the perturbation of the phospholipid membrane, and as a result, the peptides were embedded in the membrane.
Antioxidant Activities of Dihydric Phenol Derivatives for the Autoxidation of Tetralin
Authors: Yamamura Tatsuo , Nishiwaki Kazuhiro , Tanigaki Yasumitsu , Terauchi Susumu , Tomiyama Shogo , Nishiyama Tomihiro 
Published: July 2006

Abstract
The antioxidant activities of dihydric phenols, such as catechol, resorcinol, and hydroquinone, and their twenty-three alkyl and benzyl substituted derivatives were evaluated by means of an oxygen-absorption method at 60 °C for determining the oxidation of tetralin. Catechols exhibited a much higher stoichiometric factor (2.0—2.3) compared with those of other compounds. The stoichiometric factors of hydroquinones (0.6—1.1) are almost half those of catechols, and are lower for the resorcinols (0.3—0.6). In addition, the rates of oxidation during the induction period (Rinh) were 1.1—1.6 × 10−6, 3.0—3.8 × 10−6, and 13.3—18.4 × 10−6 M min−1 for catechols, hydroquinones, and resorcinols, respectively. According to these results, catechols and hydroquinones are efficient antioxidants, and their activities may be dependent on the stability of phenoxyl radicals as oxidation products due to the formation of the quinone structure. Furthermore, the stability of phenoxyl radicals derived from catechols is higher than that of those from hydroquinones. In spite of having two OH substituents, resorcinols behave as monohydric phenols in the reaction with peroxyl radicals.
Theoretical Analysis of Adsorption Properties and Vibrational Behavior of O2 on Ag (110) Surface with Ab Initio CM and DAM Calculations
Authors: Fan Kangnian , Wang Wenning , Deng Jingfa 
Published: July 2006

Abstract
Chemisorption properties and vibrational behaviors of molecular oxygen on Ag (110) surface have been studied by the cluster model (CM) and dipped adcluster model (DAM) with an Ag6 cluster. Two stable states, 1A1 [] and 3A2 [001], have been found and assigned to peroxide (O22−) and superoxide (O2−) species, respectively. Theoretically predicted adsorption geometries and vibrational frequencies for these states are similar to those measured in the experiments. With the DAM method, the calculated adsorption energies agree well with the experimental value. The O22− species is predicted to be more stable than the O2− species. Cluster size and basis set effects have also been investigated.