bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and numerical validation of a finite element model of the muscle standardized femur
Authors: Polgar K , Gill H S , Viceconti M , Murray D W , O'Connor J J
Published: May 2003

The human femur is one of the parts of the musculo-skeletal system most frequently analysed by means of the finite element (FE) method. Most FE studies of the human femur are based on computed tomography data sets of a particular femur. Since the geometry of the chosen sample anatomy influences the computed results, direct comparison across various models is often difficult or impossible.

The aim of the present work was to develop and validate a novel three-dimensional FE model of the human femur based on the muscle standardized femur (MuscleSF) geometry. In the new MuscleSF FE model, the femoral attachment of each muscle was meshed separately on the external bone surface. The model was tested under simple load configurations and the results showed good agreement with the converged solution of a former study. In the future, using the validated MuscleSF FE model for numerical studies of the human femur will provide the following benefits: (a) the numerical accuracy of the model is known; (b) muscle attachment areas are incorporated in the model, therefore physiological loading conditions can be easily defined; (c) analyses of the femur under physiological load cases will be replicable; (d) results based on different load configurations could be compared across various studies.
Strain distribution within the human femur due to physiological and simplified loading: Finite element analysis using the muscle standardized femur model
Authors: Polgar K , Gill H S , Viceconti M , Murray D W , O'Connor J J
Published: May 2003

The aim of the current work was to study the effect of simplified loading on strain distribution within the intact femur using the Muscle Standardized Femur finite element model and to investigate whether the interaction between the intact human femur and the muscles which are attached to the bone surface could accurately be represented by concentrated forces, applied through the centroids of their attachment areas. An instant at 10 per cent of the gait cycle during level walking was selected as the reference physiological load case; nine load cases were analysed. Comparison of the calculated results for the physiological load case with muscle forces uniformly distributed over their attachment areas showed good agreement with in vivo measurements of strain values and femoral head displacement in humans. Simplified load cases generated unrealistic displacement results and high strain magnitudes, exceeding the physiological range. It was found that when muscles with large attachment areas are included in the model and the muscle forces are simplified, stress and strain distributions will be affected not only on the external bone surface in the vicinity of the load application node, but also on the internal surface of the cortical bone. However, applying muscle forces as concentrated loads at the centroids of the attachment areas can serve as first indicators of the physiological stress and strain levels, if results from nodes and elements in the vicinity of the load application nodes are discarded. Omitting muscle forces or fixing the femur in mid-shaft leads to large unphysiological strain values.
Elastohydrodynamic lubrication analysis of a functionally graded layered bearing surface, with particular reference to ‘cushion form bearings’ for artificial knee joints
Authors: Virdee S S , Wang F C , Xu H , Jin Z M
Published: May 2003

Elastohydrodynamic lubrication of a functionally graded layered (FGL) bearing surface, whose elastic modulus increases with depth from the bearing surface, was investigated in this study. The finite difference method was employed to solve the Reynolds equation, simultaneously with the elasticity equation of the bearing surface, under circular point contacts. The finite element method was adopted to solve the elasticity equation for the FGL bearing surface. The displacement coefficients thus obtained were used to calculate the elastic deformation of the bearing surface, required for the elastohydrodynamic lubrication analysis. Good agreement of the predicted film thickness and pressure distribution was obtained, between the present method and a previous study for a single layered bearing surface with a uniform elastic modulus. The general numerical methodology was then applied to an FGL bearing surface with both linear and exponential variations in elastic modulus, with particular reference to the ‘cushion form bearing’ for artificial knee joints. The predicted film thickness and pressure distribution were shown to be quite close to those obtained for a single layer under typical operating conditions representative of artificial knee joints, provided that the elastic modulus of the single layer was chosen to be the average elastic modulus of the graded layer.
The influence of stem insertion rate on the porosity of the cement mantle of hip joint replacements
Authors: Baleani M , Fognani R , Toni A
Published: May 2003

This study investigates the effect of stem insertion rate on the porosity of the cement mantle. An experimental protocol was developed to simulate the surgical technique of cementing a prosthetic stem into the medullary canal of the femur. Cement mantle specimens were produced for three different stem insertion rates. The presence of porosity in the cement mantle was investigated. Additionally, the mechanical strength of the bone cement was assessed. Increasing the stem insertion rate did not have a significant effect on the porosity distribution within the bulk cement mantle. However, for all stem insertion rates investigated, the porosity concentration increased significantly moving from the cement/pseudofemur interface through to the stem/cement interface. In all cases, the presence of porosity significantly decreased the mechanical behaviour of the bone cement. High porosity concentration at the stem/cement interface seems to be attributed also to the rheology of the cement during implant insertion. Nevertheless, the surgeon cannot influence the formation of porosity by changing the stem insertion rate.
Contact mechanics of metal-on-metal hip implants employing a metallic cup with a UHMWPE backing
Authors: Liu F , Jin Z M , Grigoris P , Hirt F , Rieker C
Published: May 2003

The contact mechanics in metal-on-metal hip implants employing a cobalt chromium acetabular cup with an ultra-high molecular weight polyethylene (UHMWPE) backing were analysed in the present study using the finite element method. A general modelling methodology was developed to examine the effects of the interfacial boundary conditions between the UHMWPE backing and a titanium shell for cementless fixation, the coefficient of friction and the loading angle on the predicted contact pressure distribution at the articulating surfaces. It was found that the contact mechanics at the bearing surfaces were significantly affected by the UHMWPE backing. Consequently, a relatively constant pressure distribution was predicted within the contact conjunction, and the maximum contact pressure occurred towards the edge of the contact. On the other hand, the interfacial boundary condition between the UHMWPE backing and the titanium shell, the coefficient of friction and the loading angle were found to have a negligible effect on the contact mechanics at the bearing surfaces. Overall, the magnitude of the contact pressure was significantly reduced, compared with a similar cup without the UHMWPE backing. The importance of the UHMWPE backing on the tribological performance of metal-on-metal hip implants is discussed.
Mechanical anisotropy of the human knee articular cartilage in compression
Authors: Jurvelin J S , Buschmann M D , Hunziker E B
Published: May 2003

Articular cartilage exhibits anisotropic mechanical properties when subjected to tension. However, mechanical anisotropy of mature cartilage in compression is poorly known. In this study, both confined and unconfined compression tests of cylindrical cartilage discs, taken from the adult human patello-femoral groove and cut either perpendicular (normal disc) or parallel (tangential disc) to the articular surface, were utilized to determine possible anisotropy in Young's modulus, E, aggregate modulus, Ha, Poisson's ratio, v and hydraulic permeability, k, of articular cartilage. The results indicated that Ha was significantly higher in the direction parallel to the articular surface as compared with the direction perpendicular to the surface ( Ha = 1.237 ± 0.486 MPa versus Ha = 0.845 ± 0.383 MPa, p = 0.017, n = 10). The values of Poisson's ratio were similar, 0.158 ± 0.148 for normal discs compared with 0.180 ± 0.046 for tangential discs. Analysis using the linear biphasic model revealed that the decrease of permeability during the offset compression of 0–20 per cent was higher ( p = 0.015, n = 10) in normal (from 25.5 × 10− 15 to 1.8 × 10−15 m4/N s) than in tangential (from 12.3 × 10− 15 to 1.3 × 10− 15 m4/N s) discs. Based on the results, it is concluded that the mechanical characteristics of adult femoral groove articular cartilage are anisotropic also during compression. Anisotropy during compression may be essential for normal cartilage function. This property has to be considered when developing advanced theoretical models for cartilage biomechanics.
Fatigue strength of a wire passing through a cannulated screw: Implications for closure of the sternum following cardiac surgery
Authors: Jutley R S , Shepherd D E T , Hukins D W L
Published: May 2003

It has been proposed that the incidence of sternal dehiscence can be decreased by passing the wires used for sternotomy closure through cannulated screws. However, there is a potential risk of fatigue failure as a result of the wire moving against the screw, e.g. during coughing and sneezing. The system of cannulated screws and wire was subjected to static tensile testing to failure. Five tests were performed and failure occurred at 388 ± 34 N (mean ± SD). Ten cyclic tests were then performed. Sinusoidal loading was applied at 10 Hz with peak forces in the range 10–90 per cent of the static failure force, at a constant load ratio R = 10. The test with the lowest peak force reached run-out at 6 × 106 cycles. The others failed by the ends of the wire closures becoming untwisted (one test), the wire fracturing at the twist (three tests) or the wire fracturing at the screw (five tests). However, calculations based on these results suggest that fatigue failure is unlikely to occur as a result of regular breathing or continuous coughing or sneezing.
Synthesis and Structures of Novel Discrete Ni(II)–Ln(III) Heterodinuclear Complexes (Ln = Gd or Lu)
Authors: Kondoh Nobuyuki , Shimizu Yuko , Kurihara Masato , Sakiyama Hiroshi , Sakamoto Masatomi , Nishida Yuzo , Sadaoka Yoshihiko , Ohba Masa-aki , Okawa Hisashi
Published: May 2003

The first discrete NiLn heteronuclear complexes, [Ni(salabza)Ln(hfac)3] (Ln = Gd(III) and Lu(III)), were synthesized, where H2salabza and Hhfac denote N,N′-bis(salicylidene)-2-aminobenzylamine and 1,1,1,5,5,5-hexafluoroacetylacetone, respectively. Structural analyses revealed that the Ni(II) and Ln(III) ions are bridged by the two phenolate oxygen atoms of salabza2− and that the shortest intermolecular separation is > 5.9 Å for the Ni–Ni distance, indicating that the present complexes consist of a discrete dinuclear NiLn unit.
Synthesis, Structure and Magnetic Property of a Tetranuclear Iron(III) Complex of “Face-to-Face” Type
Authors: Miyasato Yûji , Nogami Yoshihiro , Ohba Masaaki , Sakiyama Hiroshi , Okawa Hisashi
Published: May 2003

A tetranuclear iron(III) complex [{Fe2(L)(AcO)}2(O)2](PF6)2 of the macrocyclic dinucleating ligand (L2−) derived from the [2+2] condensation between 2,6-diformyl-4-methylphenol and 1,3-diaminopropane has a “face-to-face” structure, comprising two dinuclear {Fe2(L)(AcO)}3+ units connected by two oxo bridges.
Synthesis of Carboxymethyl GLA-60 Ether Derivatives Containing an Olefin in Their Chains and Their LPS-Antagonistic Activities
Authors: Nakamura Tsuyoshi , Watanabe Yukiko , Shiozaki Masao , Kanai Saori , Kurakata Shin-ichi
Published: May 2003

Anomeric carboxymethyl GLA-60 olefine derivatives having ether chains instead of ester chains in their side chains were synthesized and their biological activities toward both human U937 cells and mouse PEC-macrophage cells were measured. The species-specific behavior of these compounds in humans (LPS-antagonistic) and mice (very weak LPS-antagonistic, but almost inactive) found this time was different from that in humans (LPS-antagonistic) and mice (endotoxic) found in the biosynthetic precursor of lipid A, such as lipid IVa. However, this fact also shows, interestingly enough, that a difference exists in the molecular recognition between human and mouse LPS receptors.
Palladium-Catalyzed Addition of Tetragermetanes to Alkynes
Authors: Mochida Kunio , Hirakue Katsuhiko , Suzuki Kaoru
Published: May 2003

1,1,2,2,3,3,4,4-Octaisopropyltetragermetane (iPr2Ge)4 reacted with various alkynes in the presence of palladium complexes at 120 °C to afford 1,2,3,4-tetrahydro-1,2,3,4-tetragermins, Δ4-1,2,3-trigemolene, and 1H-germoles, depending on the kind of alkyne and the palladium complex employed. Terminal alkynes are more reactive than internal ones. Pd(dba)2-ETBP and Pd(acac)2-ETBP systems were found to serve as efficient catalysts. The mechanism of alkyne insertion reactions into the germanium–germanium bonds of (iPr2Ge)4 is discussed.
Oxidizing Ability of a Series of (Tropon-2-ylimino)pnictoranes (Pnictogen = P, As, Sb, and Bi) toward Some Alcohols
Authors: Mitsumoto Yuhki , Nitta Makoto
Published: May 2003

In order to gain a better understanding of the oxidizing ability of a series of (tropon-2-ylimino)pnictoranes of the general structure Ph3M=NR (R = tropon-2-yl; M = P, As, Sb, and Bi), reactions were run with some alcohols such as benzopinacol (1,1,2,2-tetraphenyl-1,2-ethanediol), benzoin, cinnamyl alcohol, 1-phenylethanol, a mixture of cis- and trans-4-t-butylcyclohexanol, 2-phenylethanol, and 1-phenyl-1,3-propandiol. Iminophosphorane oxidized only benzopinacol to give benzophenone, while both arsorane and stiborane oxidized benzopinacol and benzoin to give benzophenone and benzil, respectively. On the other hand, iminobismuthorane has appreciable oxidizing ability, and reacted with the alcohols mentioned above, except the primary alcohol, to give the corresponding carbonyl compounds. Iminobismuthorane reacted with 1-phenyl-1,3-propandiol selectively to oxidize benzyl alcohol moiety, but not a primary alcohol moiety, to give 3-hydroxy-1-phenyl-1-propanone. Thus, the oxidizing ability of a series of (tropon-2-ylimino)pnictoranes is demonstrated to be in the order of iminophosphorane < iminoarsorane < iminostiborane < iminobismuthorane: the dipolar (degree of contribution of the Ph3M+–−NR canonical structure) and electrophilic character of pnictogen elements of a series of iminopnictoranes appear to increase their oxidizing ability when the pnictogen stands lower in the periodic table.
Reexamination of Cyclodextrin-Induced Conformational Enantiomerism of Bilirubin in Aqueous Solution
Authors: Kano Koji , Imaeda Kinuyo , Ota Kenichi , Doi Ryoji
Published: May 2003

A cyclodextrin (CDx)-induced conformational enantiomerism of bilirubin IXα in dianionic form (BR2−) was reinvestigated to establish the mechanism for complexation of BR2− with native CDxs, such as α-, β-, and γ-CDxs, in aqueous solution. Since previous studies have lacked NMR examinations, we concentrated our effort on measuring the 1H NMR spectra to determine the structure of the BR2−–CDx complex, where BR2− takes the (M)-helix conformation. Circular dichroism (CD) spectroscopy was also utilized. 1H NMR measurements including ROESY suggest the shallow penetration of a hydrophobic part of BR2− into the CDx cavity. 1H NMR data also show adsorption of the BR2− dianion on the outside wall of the CDx cavity. Although BR2− is adsorbed on the cavities of heptakis(2,3-di-O-methyl)- and heptakis(2,6-di-O-methyl)-β-CDxs, no enantiomerism occurred when these O-methylated β-CDxs were used in place of native CDxs. In contrast, heptakis(6-O-methyl)-β-CDx exhibits a definite (−)-to-(+) bisignate CD spectrum due to preferencial formation of (M)-helix BR2−. These results are interpreted in terms that the BR2− dianion is adsorbed on the outside wall of the asymmetrically twisted CDx cavity, and is anchored through two-point hydrogen bonding between the CO2− group(s) of BR2− and the OH groups at the 2- and 3-positions of the CDx.
Design of Reversible Low Redox Potential Systems Using Five-Membered Trichalcogenaheterocycles Containing Heavy Chalcogens; Sulfur, Selenium, and Tellurium
Authors: Nagahora Noriyoshi , Ogawa Satoshi , Yoshimura Satoko , Kawai Yasushi , Sato Ryu
Published: May 2003

4-Isopropyl-7-methoxy-1,3,2-benzodichalcogenastannoles and 2,2-bis(η5-pentamethylcyclopentadienyl)-1,3,2-benzodichalcogenatitanoles, a synthetic equivalent of unstable ortho-benzenedichalcogenol, were prepared from 2-isopropyl-5-methoxybenzenechalcogenols in moderate yields by ortho-lithiation, chalcogenation, and protection with dichlorodimethylstannane and bis(η5-pentamethylcyclopentadienyl)titanocene dichloride, respectively. Some of the solid-state structures of the new-type stannoles and titannoles were confirmed by X-ray crystallographic analyses. Transformation into 4-isopropyl-7-methoxy-1,2,3-benzotrichalcogenoles was successfully carried out, namely by reacting the stannoles or titannoles with electrophiles containing one sulfur or selenium unit. The molecular structures of the new trichalcogenoles were determined by NMR, IR, mass spectra, X-ray crystallographic analyses, and theoretical calculations. In particular, it was elucidated that heavier multi-chalcogen linkages, selenium-selenium and selenium–tellurium bonds in the benzotrichalcogenoles were present in the five-membered ring by multi-nuclear NMR spectra in solution and confirmed by X-ray crystallographic analyses in the solid-state. The redox properties of the trichalcogenoles were studied by cyclic voltammetry. The voltammograms exhibited well-defined reversible one-electron redox couples. New type radical cations were isolated in quantitative yields in the one-electron oxidation of the trichalcogenoles with equimolar amounts of NOPF6. The structures of the radical cation salts were analyzed by 31P-NMR, ESR spectra, elemental analyses, and theoretical calculations. One-electron reduction of the radical cations on treatment with one equivalent of samarium(II) iodide gave the neutral trichalcogenoles quantitatively.
Synthesis of Polycyclic Imines by Palladium-Catalyzed Domino Cyclization of Di- and Trienyl Ketone O-Pentafluorobenzoyloximes
Authors: Zaman Shazia , Kitamura Mitsuru , Narasaka Koichi
Published: May 2003

Various cyclic imines, such as spiro imines and a fused bicyclic imine, are synthesized from dienyl and trienyl ketone O-pentafluorobenzoyloximes by the domino amino-Heck reaction. Treatment of the oximes with a catalytic amount of Pd(PPh3)4 and triethylamine gives polycyclic imines in high yields via alkylideneaminopalladium(II) intermediates generated in situ by the oxidative addition of the oximes to the Pd(0) complex.
Synthesis of Primary Amines and N-Methylamines by the Electrophilic Amination of Grignard Reagents with 2-Imidazolidinone O-Sulfonyloxime
Authors: Kitamura Mitsuru , Chiba Shunsuke , Narasaka Koichi
Published: May 2003

2-Imidazolidinone O-sulfonyloxime reacts with various aryl and alkyl Grignard reagents as an electrophilic amination reagent, giving N-alkylated imines. The resulting imines are transformed to primary amines and N-methyl secondary amines by hydrolysis with CsOH and LiAlH4 reduction, respectively.
Friedel–Crafts Acetylation, Propionylation, and Butyrylation of Toluene Catalyzed by Solid Superacids
Authors: Nakamura Hideo , Kashiwara Yuki , Arata Kazushi
Published: May 2003

The liquid–solid phase acetylation of toluene with acetic anhydride was carried out over solid superacids of sulfated metal oxides (SO4/MeOx) and supported metal oxides (Me1Ox/Me2Oy) selected from the results in the benzoylation of toluene with benzoic anhydride [K. Arata, H. Nakamura, and M. Shouji, Appl. Catal. A: General, 197, 213 (2000)]. The reaction was conducted by adding dropwise a mixture of 2 mmol of acetic anhydride and 2 mL of toluene onto 0.5 g of catalyst suspended in 13 mL of toluene with stirring at 110 °C in the first period of 30 min, followed by stirring the mixture for 2 h. The yields of 2′-, 3′-, and 4′-methylacetophenones in the distribution of 9–10% 2′-, 1–2% 3′- and 89–90% 4′-isomers were 24 and 13% for the sulfated metal oxides of SO4/ZrO2 and SO4/SnO2, those by Pt and Ru promoted sulfated zirconias (Pt-, Ru-SO4/ZrO2) being 21 and 28%, respectively. The supported metal oxides of Fe2O3/ZrO2 and WO3/ZrO2 gave yields of 18 and 15%, respectively. The propionylation and butyrylation of toluene with propionic and butyric anhydrides were performed over SO4/ZrO2, SO4/SnO2, Pt-SO4/ZrO2, and Ru-SO4/ZrO2; the yields of 7–9% o- and 91–93% p-isomers were 31, 26, 32, and 44% for propionylation and 46, 29, 44, and 55% for butyrylation, respectively. The SO4/ZrO2 catalyst gave a 100% yield of 4′-methoxyacetophenone for the acetylation of anisole with acetic anhydride.
Laser Heating Dynamics of Poly(methyl methacrylate) Films Doped with Aromatic Molecules as Revealed by Analysis of Diffusion of Triplet States
Authors: Fujiwara Hisashi , Ishii Hiroshi , Ishiwata Takashi , Hayashi Takashi , Fukumura Hiroshi , Masuhara Hiroshi
Published: May 2003

The 248 nm laser heating dynamics of poly(methyl methacrylate) (PMMA) doped with biphenyl or p-terphenyl was studied quantitatively by the analysis of temperature-dependent T1-T1 annihilation, which is a result of the thermally-activated diffusion of the dopants. The values of the second-order rate constant k2 (M−1 s−1) for the annihilation were obtained at several temperatures (293–363 K) under weak laser excitation (2–4 mJ cm−2). Arrhenius plots of k2 for both films resulted in straight lines that were used to estimate the rate constant at higher temperatures for the simulation of T1-T1 annihilation. Under intense excitation (100–190 mJ cm−2), the T1 decays of both films occurred faster with increased laser fluence. The comparison between these observed T1 decays and the simulated ones revealed the following: (1) most of the absorbed photon energy, at least 70%, is used to increase the temperature of the polymer, (2) the cooling of the polymer, mainly due to heat transfer into the quartz substrate, slows down the diffusion of the dopants and, accordingly, the T1-T1 annihilation, and (3) the temperature at the polymer-quartz interface after laser excitation remains almost constant up to at least a few microseconds.
Development of a Colloid Chemical Process for Magnetic Seeding to Organic Dye
Authors: Takeda Shin-ichi , Yu Sung-Jin , Tari Isao , Nishijima Shigehiro , Nakahira Atsushi
Published: May 2003

The recovery of organic dye molecules was achieved by using a colloidal magnetic seeding process under high-gradient magnetic separation. The recovery fraction of dye molecules was dependent on the adsorption capacity of the dye molecules. A magnetic colloid can recover a much greater amount of dye molecules than magnetite particles. The adsorption of orange II molecules was found to be an irreversible process, and orange II molecule could be more tightly adsorbed on a magnetic colloid than a magnetite particle surface.
Formation and Dissociation Dynamics of Molecular Superexcited States
Authors: Hatano Yoshihiko
Published: May 2003

This is a survey of recent progress in experimental studies of spectroscopy and dynamics of molecules in the superexcited states. The Platzman’s concept of the superexcited states deduced from the theoretical analysis of the interaction of ionizing radiation with matter has been recently substantiated experimentally. Most of the observed superexcited states are assigned to high Rydberg states which are vibrationally (and/or rotationally), doubly, or inner-core excited, and converge to each ion state. Non-Rydberg superexcited states are also observed. The dissociation dynamics of these states as well as the products are very different from those of the lower states excited below ionization thresholds. The neutral dissociation is unexpectedly more important than ionization. Molecular superexcited states are described as reaction intermediates in some fundamentally important collision processes, e.g., electron-ion or ion-ion recombination, Penning ionization, and electron attachment, and are described also as important species in the primary processes of radiation chemistry, VUV-photochemistry, and plasmas. Comments are presented on molecular superexcited states in the condensed phase. Finally, the future perspectives of the present studies are summarized.
Biscycloaddition to [60]Fullerene: Regioselectivity and Its Control with Templates
Authors: Nakamura Yosuke , O-kawa Kyoji , Nishimura Jun
Published: May 2003

Compared to [60]fullerene monoadducts, there have been far fewer examples of the investigation of bisadducts, mainly due to the difficulties in their isolation and characterization. Unless appropriate templates are employed, bisadditions generally proceed with low regioselectivity, resulting in the formation of complex regioisomeric mixtures. This account deals with the regioselectivity in typical bisadditions in the absence of templates and the spectroscopic features available for the characterization of the bisadducts produced. The observed regioselectivity can be reasonably explained by a combination of the steric reasons and the coefficients of frontier orbitals in the corresponding monoadducts. Although it depends on the reactive species whether HOMO or LUMO is involved, e isomer is always preferable. In order to accomplish regioselective synthesis of bisadducts, several research groups have developed a synthetic methodology by using tethers as covalent templates. This account describes the regioselectivity in bisadditions accomplished by templating tethers, mainly focusing on Diels–Alder reactions.
Synthesis of [Al]-SSZ-31 Molecular Sieves Using [Al]-Beta Zeolite ([Al]-BEA) as Precursors
Authors: Ahedi Ranjeet Kaur , Kubota Yoshihiro , Pusparatu  , Sugi Yoshihiro
Published: May 2003

The aluminosilicate version of SSZ-31 ([Al]-SSZ-31) zeolite was synthesized by a new route including phase-transformation, wherein an aluminosilicate analog of beta zeolite ([Al]-BEA) was used as a precursor and 1,1,1,8,8,8-hexaethyl-1,8-diazoniaoctane dihydroxide was used as a structure-directing agent (SDA). [Al]-BEA precursors synthesized by two routes, viz. the hydrothermal (HTS) and dry-gel conversion (DGC) method, were employed for the synthesis. [Al]-SSZ-31 with a low output SiO2/Al2O3 ratio crystallized only when the precursor (SiO2/Al2O3 = 30), prepared by DGC method, was employed. Precursors synthesized by the HTS method produced highly crystalline samples, however, only in the high silica region. In general, [Al]-SSZ-31 samples over a wide range of SiO2/Al2O3 ratios could be synthesized using a precursor route. During crystallization, a phase transformation from [Al]-BEA to [Al]-SSZ-31 was observed, indicating dissolution of the beta phase, followed by its redirection towards the SSZ-31 phase in the presence of SDA. An increase in gel water helped to produce pure [Al]-SSZ-31. [Al]-SSZ-31 was found to crystallize in NaOH/SiO2 window of 0.040–0.056. Scanning electron microscopy (SEM) showed plate-like crystals of about 5 μm in size. 13C CP MAS NMR indicated that the SDA was intact inside the pores during crystallization. Furthermore, the samples were also characterized by 29Si and 27Al MAS NMR in addition to X-ray diffraction (XRD), temperature-programmed desorption of ammonia (NH3-TPD), SEM, etc.
Theory of Molecular Excitons in 1-D Crystals as Applied to a Multiple-Helix Model of Pseudoisocyanine (PIC) J Aggregates
Authors: Kanamaru Nobuaki
Published: May 2003

The theory of molecular excitons in one-dimensional (1-D) crystals with 3-D entities is developed as a modification of the existent theory (for 3-D crystals), starting from a settlement of the 1-D space group. Then, it is applied to one of the helix models of the PIC J aggregates, as postulated, to interpret various experimental facts, such as the importance of hydrophobic groups and evidence of a core, i.e. a building block with (at least) 8 PIC molecules. Through the development of a formalism, the absorption and rotation of light by a helix with more than two spirals (2 × 4 = 8 spirals corresponding to 4 double linear arrays, actually) are estimated and found to be consistent with the observed polarized absorption and circular dichroic spectra of the aggregates.
Coexistence of Two 1:1 Complexes of Oxyphenonium Bromide and α-Cyclodextrin
Authors: Funasaki Noriaki , Yamaguchi Hiroshi , Ishikawa Seiji , Neya Saburo
Published: May 2003

The complexation of 2-(2-cyclohexyl-2-hydroxy-2-phenylacetoxy)-N,N-diethyl-N-methylethanaminium bromide (oxyphenonium bromide, OB) and α-cyclodextrin (α-CD) in deuterium oxide was investigated by 500 MHz proton NMR spectroscopy, molecular mechanics, and molecular surface-area calculations. The ROESY spectrum revealed that two 1:1 complexes of OB and α-CD, the phenyl-in complex and the cyclohexyl-in complex, coexist simultaneously. The ROE intensities of intermolecular cross-peaks and molecular-mechanics calculations provided the structures of these complexes. The ROE intensities were well-correlated with the effective inter-proton distances for the estimated structures. The observed binding constant (70 dm3 mol−1) was close to the sum of the binding constants of α-CD with phenol and cyclohexanol. This agreement supported the coexistence of the two complexes, and allowed us to estimate the mole fraction of the phenyl-in complex of 0.3. The chemical shift variations (ΔδOB–CD) at full binding for aromatic protons of OB are smaller than those of the benzenesulfonate–α-CD complex. Their ratio gave another estimate of the phenyl-in complex mole fraction (0.38). The averaged structure of OB in the two complexes was estimated from a comparison between the observed and theoretical shifts for four pairs of cyclohexyl protons; the phenyl and cyclohexyl groups in the complexes are slightly more distant than those in the free state. The structures of the phenyl-in complex and the cyclohexyl-in complex, estimated by hydrophobic molecular surface-area calculations, predicted binding constants closer to the observed ones than those by molecular-mechanics calculations.
Strength of the Translation Initiation Signal Sequence of mRNA as Studied by the Quantification Method: Effect of Nucleotides at Positions from +4 to +6 upon the Recognition of ATG and Alternative Initiation Codons
Authors: Iida Yôichi , Kanagu Daisuke
Published: May 2003

Concerning the translation initiation signal in vertebrate mRNAs, although a consensus sequence, (GCC)GCC(A or G)CCATGG, has been proposed, the actual initiation sequences differ from it to a greater or lesser degree. Kozak monitored selection by ribosomes of the first versus second ATG codons as a function of introducing mutations at positions +4, +5 and +6 of the first ATG codon. Six different flanking codons, starting with G, strongly enhanced the selection of the first ATG codon. Except for T at position +5, ATG codon recognition was unaffected by most mutations at positions +5 and +6. These experimental results were analyzed using a quantification method proposed previously, and a 18-nucleotide sequence including ATG and nucleotides in positions +4, +5 and +6 was characterized by its sample score (strength of translation initiation signal). The experimental results were well understood based on the strength of the signal.
Evaporation Rate Measurement of Water and Liquid 1-Alkanols across Air–Liquid Interface Using Thermogravimetry
Authors: Rusdi Muhammad , Moroi Yoshikiyo
Published: May 2003

Evaporation rate measurements of water across air/water interface were made by using a thermogravimetry technique. A sample liquid was held in a partially filled, open-topped pan in a furnace tube, through which dry air was flowing. The effect of the flow rate of the dry air on the evaporation rate was very large at lower flow rates, while it became smaller at higher flow rates. The evaporation rate of water over the temperature range 298.2–333.2 K was studied in order to obtain the activation energy for the evaporation. The energy was found to decrease with increasing temperature. A newly developed equation was used to analyze the evaporation rate. Purified liquid 1-alkanols (carbon number = 4, 6, 8, 10, and 12) were employed as test substances in order to estimate the effects of terminal –CH2OH group and of residual CH2 groups on the activation energy. The contribution of –CH2OH group to the activation energy was found to slightly decrease with increasing temperature, while the contribution of residual CH2 group increased with increasing chain length; the temperature-dependence remained almost the same irrespective of the alkyl chain.
Detection of Ascorbic Acid in an Ethanol–Water Mixed Solution on a Conductive Diamond Electrode
Authors: Komatsu Masaharu , Fujishima Akira
Published: May 2003

Conductive boron-doped diamond thin-film electrodes have been shown to be highly suitable as electrochemical detectors in flow injection analysis (FIA) due to the lack of electrode deactivation due to fouling and the ability to withstand highly positive electrochemical potentials. In the present work, a diamond electrode was applied to the detection of ascorbic acid (AA) in an alcohol–water mixed solution. During FIA of AA in an ethanol (EtOH)–water solution including 0.1 M NaClO4, the interference from EtOH oxidation that would have been observed with a Pt electrode was avoided, and the amperometric response for AA was observed with the use of a conductive diamond as the electrode material. Moreover, The detection limit for AA that could be observed was lower than that for a glassy carbon electrode, because diamond exhibits a lower background current, smaller background noise, and smaller injection noise. These findings suggest that the diamond electrode may be applied in the detection of other redox-active impurities and added substances in alcohol or alcohol–water solutions, such as chlorophyll, nicotinamide, caffeine, riboflavin, and dl-α-tocopherol.
Hydration Structure of Alanine Molecule in Concentrated Aqueous Solutions
Authors: Kameda Yasuo , Sugawara Kentaro , Usuki Takeshi , Uemura Osamu
Published: May 2003

Time-of-Flight (TOF) neutron diffraction measurements have been carried out on aqueous 3 mol% d,l-alanine solutions. The isotopic substitution technique has been applied to both nitrogen and methyl-hydrogen atoms within the alanine molecule in order to obtain information concerning the hydration structure around the amino- and the methyl groups within the alanine molecule in the aqueous solution. There exist, on the average, 2.4(1) water molecules that are hydrogen bonded to the amino group with an intermolecular distance of rNO = 2.88(2) Å. The tilt angle between the N–D···O axis and the molecular plane of the D2O molecule has been determined to be 60.4(5)°. The first hydration shell of the methyl group involves ca. two water molecules per one alanine molecule. The nearest neighbor HM(methyl)–OW(water) and HM(methyl)–HW(water) distances have been determined to be 2.58(1) and 2.99(2) Å, respectively.
Electronic and Magnetic Properties of Organic Conductors (DMET)2MBr4 (M = Fe, Ga)
Authors: Enomoto Kengo , Yamaura Jun-Ichi , Miyazaki Akira , Enoki Toshiaki
Published: May 2003

(DMET)2MBr4 (M = Fe, Ga) are isostructural organic conductors whose crystal structure consists of an alternate stacking of quasi one-dimensional chain-based donor layers and anion square lattices. The resistivity, ESR, magnetic susceptibility, magnetization, and magnetoresistance of these salts were investigated in order to clarify the correlation between the electronic structure and the magnetism. The electronic structures of both salts are metallic down to TMI ∼40 K, below which a Mott insulating state is stabilized, accompanied by an SDW transition at TSDW ∼25 K. The FeBr4 salt with Fe3+ (S = 5/2) localized spins undergoes an antiferromagnetic transition at TN = 3.7 K. In the FeBr4 salt, the magnetization curves, which show field-direction-dependent anomalies in addition to a spin-flop transition, are demonstrated to have a participation of donor π-electron spins in the magnetization processes. The field dependence of the magnetoresistances below TN tracks faithfully that of the magnetization, where the donor π-electrons and Fe3+ d-electrons are responsible for the former and the latter, respectively. This clearly demonstrates the presence of the π–d interaction that plays an important role in the interplay between electron transport and magnetism.
Photophysical and Photochemical Processes of Poly(methylphenylsilane) Functionalized with Pendant p-Nitroazobenzene Groups
Authors: Zhao Changli , Horiuchi Hiroaki , Okutsu Tetsuo , Tobita Seiji , Takigami Shoji , Hiratsuka Hiroshi
Published: May 2003

The synthesis of poly(methylphenylsilane) functionalized with pendant p-nitroazobenzene groups (PMPS-azo) has been carried out, and their photophysical and photochemical processes have been studied. The fluorescence quantum yields of PMPS-azo decrease with an increase of the amounts of the pendant p-nitroazobenzene groups. The picosecond fluorescence decay kinetics of PMPS-azo was interpreted in terms of not only the energy transfer, but also the electron transfer from the Si–Si main chain to the pendant p-nitroazobenzene group. The evidence for intramolecular electron transfer was provided by the formation of the radical anion of the pendant trans-p-nitroazobenzene group upon steady-state photolysis of PMPS-azo at 77 K.
Appearance of Phosphate-Selectivity by Hydrolytic Trimerization of Simple Dialkyltin(IV) Compounds Used as Carrier
Authors: Yuchi Akio , Kani Shinpei , Suzuki Takashi , Hattori Hiroyuki
Published: May 2003

The complexation equilibria of dimethyltin(IV) and trimethyltin(IV) ions with several anions in aqueous solutions were potentiometrically studied as a model of the interaction of lipophilic dialkyltin(IV) and trialkyltin(IV) compounds, the carriers of ion-selective electrodes, with anions in the membrane phase. Phosphate and arsenate reacted with dimethyltin(IV) ion to yield partially hydrolyzed trimeric species, [(SnMe2)3(OH)2(HPO4)2] and [(SnMe2)3(OH)2(HAsO4)2]. Such oligomerization, which ensures the interaction of phosphates or arsenate with two Sn centers, is also possible for lipophilic dialkyltin(IV) compounds. Moreover, shielding these anions from the solvent by lipophilic alkyl groups projected from Sn atoms may enhance the distribution of the carrier-anion associates into the membrane phase. These cooperate to give lipophilic dialkyltin(IV) compounds with high selectivities to these ions. The presence of such electroactive species in the membrane phase was discussed with reference to the previous studies.
Synthesis and Photochemical Properties of Novel Ruthenium(II)-Nickel(II) and Ruthenium(II)-Copper(II) Dinuclear Complexes
Authors: Onozawa-Komatsuzaki Nobuko , Katoh Ryuzi , Himeda Yuichiro , Sugihara Hideki , Arakawa Hironori , Kasuga Kazuyuki
Published: May 2003

Novel Ru(II)-Ni(II) and Ru(II)-Cu(II) dinuclear complexes have been synthesized and characterized. In these complexes, the ruthenium(II) polypyridyl group and the Ni(II)- or Cu(II)-Schiff base units are fused together by a bridging ligand, 5,6-di(salicylidenamino)-1,10-phenanthroline. X-ray crystallography on the Ru(II)-Ni(II) dinuclear complex shows that the Ni(II)-Schiff base unit is distorted against the plane of the phenanthroline ring due to the effect of a steric repulsion between the phenanthroline ring and the Ni(II)-Schiff base unit. The properties of the excited states of the dinuclear complexes are discussed by comparing them with that of the Ru(II)-Zn(II) analogue as a reference compound. These complexes show the emission from the excited state, which is assigned to MLCT0 (the excited state due to the transition from Ru(II) to the bridging ligand). For the Ru(II)-Cu(II) complex, the lifetime of the emission is found to be 80 ns, which is identical to that of the Ru(II)-Zn(II) analogue, suggesting that no quenching process exists. On the contrary, for the Ru(II)-Ni(II) complex, the emission decays very rapid. The energy transfer to the Ni(II)-Schiff base unit deactivates the MLCT0 excited state.
Preconcentration of Catecholamines into Liposomes with Imposed pH Gradients
Authors: Ishida Akihiko , Ikemoto Manabu , Ishida Yoshiki , Kamidate Tamio
Published: May 2003

The preconcentrations of epinephrine (EP) and norepinephrine (NE) into phosphatidylcholine liposomes with imposed pH gradient across the membrane were investigated by adding the catecholamine (CA) to the external medium of liposomes. To determine the CAs entrapped into liposomes, a simple method was also developed, based on the adsorption of CAs onto alumina and chemiluminescence detection. The uptake of the CAs into the liposomes was examined over a wide ΔpH range of 0–5 units (internal pH 5.0). The maximum uptakes of EP and NE were 70% and 88%, respectively, around an external pH of 9 (ΔpH 4), where zwitterionic species of EP and NE are dominant. The final concentrations of EP and NE in internal volumes were 34- and 43-fold greater than the initial concentrations of EP and NE, respectively. The uptake of the CAs was studied by using a mathematical model, which indicates that the uptake is contributed by the molar fraction of the zwitterion species in the external volume as well as the pH gradient. The uptake of EP was found to suffer from a steric hindrance due to a methyl group substituted for the hydrogen of the amino group. This study proves the capability of the liposomes for accumulation media of CAs.
Synthesis and Crystal Structure of N-Heterocyclic Carbene Complexes of Bis(η5-cyclopentadienyl)molybdenum
Authors: Yamaguchi Yoshitaka , Oda Ryoji , Sado Katsunori , Kobayashi Kimiko , Minato Makoto , Ito Takashi
Published: May 2003

The one-pot reaction of [Mo(η5-C5H5)2(H)(OTs)] (1) with 1,3-diisopropylimidazolium chloride (IiPr·HCl, 2a) in the presence of two equivalents of KOtBu in THF gave a bis(η5-cyclopentadienyl)molybdenum derivative bearing the 1,3-diisopropylimidazol-2-ylidene ligand, [Mo(η5-C5H5)2(IiPr)] (3a). 1,3-Dimethyl- and 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene coordinated molybdenocene complexes (3b, 3c) were prepared in a similar fashion (Method A). The treatment of [Mo(η5-C5H5)2(H)Li]4 (6-Mo) with the corresponding imidazolium salt in THF under photo-conditions also gave carbene complexes 3a–3c (Method B). X-ray crystal structure analyses of 3a and 3b revealed that the N-heterocyclic carbene ligand is bonded to a bent molybdenocene skeleton. The Mo–C(carbene) bond distances are 2.219(7) Å for 3a and 2.212(6) Å for 3b. The five-membered carbene ligand in both complexes is located on the bisecting plane between two cyclopentadienyl rings.
Kinetics and Mechanism for the Metalation Reaction of 5,10,15,20-Tetrakis(pentafluorophenyl)porphyrin with Diaquabis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)nickel(II) in Supercritical Carbon Dioxide
Authors: Liu Shijun , Inada Yasuhiro , Funahashi Shigenobu
Published: May 2003

The nickel(II) ion incorporation reaction into 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (H2tpfpp) to form the [Ni(tpfpp)] complex has been kinetically investigated using diaquabis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)nickel(II), [Ni(hfac)2(H2O)2], in supercritical carbon dioxide (scCO2) medium in a spectrophotometric cell at various temperatures and pressures. The metalation reaction is first order with respect to porphyrin under the conditions where [Ni(hfac)2(H2O)2] is in a large excess relative to H2tpfpp. The saturation dependence was observed for the conditional first-order rate constants as a function of the mole fraction (xNi) of the excess [Ni(hfac)2(H2O)2]. Such dependence suggests that the metalation reaction consists of a fast pre-equilibrium of the formation of the outer-sphere association between [Ni(hfac)2(H2O)2] and H2tpfpp and a first-order rate-determining nickel(II) ion incorporation into the porphyrin core. The conditional first-order rate constants kobs are well expressed by kobs = KkxNi/(1 + KxNi), where K is the equilibrium constant for the formation of the outer-sphere association and k is the first-order rate constant for the nickel(II) ion incorporation. The thermodynamic and kinetic parameters are obtained as follows: ΔH° = 14.4 ± 1.3 kJ mol−1 at 20.5 MPa, ΔS° = 133 ± 4 J mol−1 K−1 at 20.5 MPa and ΔV° = 15 ± 1 cm3 mol−1 at 333.3 K for the pre-equilibrium; ΔH≠ = 110 ± 5 kJ mol−1 at 20.5 MPa, ΔS≠ = 22 ± 16 J mol−1 K−1 at 20.5 MPa, and ΔV≠ = 81 ± 8 cm3 mol−1 at 333.3 K for the rate-determining step. The positive change in enthalpy and volume and significant positive change in entropy strongly indicate that the outer-sphere association is derived from the desolvation of reactants in scCO2.
η3-Coordination of Hexadentate N,N,N′,N′-Tetrakis(2-pyridylmethyl)ethylenediamine (tpen) to a Mononuclear fac-ReVIIO3 Center. The Isolation of a New Class of Metal-containing Ligands
Authors: Mitani Ayako , Abe Masaaki , Tsuge Kiyoshi , Sasaki Yoichi
Published: May 2003

Reaction of ReVOCl3(PPh3)2 with an equimolar amount of tpen affords fac-[ReVIIO3(η3-tpenH)](ClO4)2 (1), in which the tpen ligand coordinates to the fac-ReVIIO3 center in a η3-mode, and the dangling bis(2-pyridylmethyl)amine arm in 1 is subsequently used to produce a heterobimetallic complex fac-, fac-[ReVIIO3(μ-η3:η3-tpen)ReI(CO)3](ClO4)2.
Synthetic Dioxygen-carrying Hemoprotein. Human Serum Albumin Including Iron(II) Complex of Protoporphyrin IX with an Axially Coordinated Histidylglycyl-propionate
Authors: Nakagawa Akito , Komatsu Teruyuki , Ohmichi Naomi , Tsuchida Eishun
Published: May 2003

Human serum albumin incorporating the iron(II) complex of protoporphyrin IX having an axially coordinated histidylglycyl-propionate formed a dioxygen-adduct complex in aqueous media (pH 7.3). The O2-binding affinity (P1/2) was 0.1 Torr at 25 °C.
Preparation and Photochemical Properties of Polyisocyanides with Regularly Arranged Porphyrin Pendants
Authors: Takei Fumie , Nakamura Sugiko , Onitsuka Kiyotaka , Ishida Akito , Tojo Sachiko , Majima Tetsuro , Takahashi Shigetoshi
Published: May 2003

A novel triblock polyisocyanide having free-base- and zinc-porphyrins as pendants was prepared by living polymerization with a Pt-Pd μ-ethynediyl complex as an initiator, and irradiated at 420 or 556 nm in a THF solution to cause intramolecular energy transfer from the zinc-porphyrin to the free-base-porphyrin.
Unsymmetrical n-Channel Semiconducting Naphthalenetetracarboxylic Diimides Assembled via Hydrogen Bonds
Authors: Katz Howard E , Otsuki Joe , Yamazaki Katsutoshi , Suka Atsushi , Takido Toshio , Lovinger Andrew J , Raghavachari Krishnan
Published: May 2003

Organic field-effect transistors have been fabricated from novel naphthalenetetracarboxylic diimides with unsymmetrical substitution. Two of these show distinct electron mobility, providing the first evidence that hydrogen bonding can be a means of producing a semiconducting morphology from organic compounds.
The SPV NO2 Gas Sensor Fabricated by Mesoporous Tin Oxide Film
Authors: Yuliarto Brian , Zhou Haoshen , Yamada Takeo , Honma Itaru , Asai Keisuke
Published: May 2003

A highly sensitive NO2 gas sensor was successfully fabricated by mesoporous tin oxide film based on surface photo voltage (SPV). The sensor measured the changes of the average value of AC photocurrent and has detection level as low as 1 ppm of NO2 gas.