bluuebunny/crossref_metadata_2025 huggingface dataset:
Ischemia-reperfusion induces G-CSF gene expression by renal medullary thick ascending limb cells in vivo and in vitro
Authors: Zhang Ying , Woodward Vanessa K. , Shelton John M. , Richardson James A. , Zhou Xin J. , Link Daniel , Kielar Mariusz L. , Jeyarajah D. Rohan , Lu Christopher Y.
Published: May 2004

Ischemic acute renal failure involves not only the kidney but also extrarenal organs such as the bone marrow that produces inflammatory cells. By ELISA and RNase protection assays, we now show that renal ischemia-reperfusion increases serum concentrations of granulocyte macrophage colony-stimulating factor (G-CSF) protein and increases both G-CSF mRNA and protein in the ischemic kidney. In situ hybridization localized the increased G-CSF mRNA to tubule cells, including medullary thick ascending limb cells (mTAL), in the outer medulla. We also show that mTAL produce G-CSF protein and increase G-CSF mRNA after stimulation by reactive oxygen species in vitro. The production of G-CSF by the kidney after ischemia-reperfusion provides a means of communication from the injured kidney to the bone marrow. This supports the known inflammatory response to ischemia.
Expression of claudin-7 and -8 along the mouse nephron
Authors: Li Wing Y. , Huey Catherine L. , Yu Alan S. L.
Published: May 2004

Claudins are integral membrane proteins of the tight junction that determine the magnitude and selectivity of paracellular permeability in epithelial tissues. The mammalian renal tubule exhibits considerable heterogeneity in the permeability properties of its different segments. To determine the nephron segment localization of claudin-7 and -8, immunofluorescence staining of mouse kidney sections was performed using isoform-specific antibodies. Claudin-8 was found to be expressed primarily at the tight junction along the entire aldosterone-sensitive distal nephron and in the late segments of the thin descending limbs of long-looped nephrons. This pattern of expression is consistent with the putative role of claudin-8 as a paracellular cation barrier. By contrast, claudin-7 was found in the same nephron segments as claudin-8, but it was expressed primarily at the basolateral membrane.
Comparison of acute and chronic antioxidant interventions in experimental renovascular disease
Authors: Chade Alejandro R. , Krier James D. , Rodriguez-Porcel Martin , Breen Jerome F. , McKusick Michael A. , Lerman Amir , Lerman Lilach O.
Published: May 2004

Reactive oxygen species (ROS) can modulate renal hemodynamics and function both directly, by leading to vasoconstriction, and indirectly, by inducing renal inflammation and tissue growth. The involvement of oxidative stress in the pathogenesis of renovascular disease (RVD) is increasingly recognized, but the relative contribution of long-term tissue injury to renal dysfunction remains unclear. We hypothesized that functional and structural alterations elicited by oxidative stress in RVD would be more effectively modulated by chronic than by acute antioxidant intervention. Renal hemodynamics and function were quantified in vivo in pigs using electron-beam computed tomography at baseline and after vasoactive challenge (ACh and sodium nitroprusside); after 12 wk of RVD (simulated by concurrent hypercholesterolemia and renal artery stenosis, n = 7); RVD acutely infused with the SOD-mimetic tempol (RVD+tempol, n = 7); RVD chronically supplemented with antioxidant vitamins C (1 g) and E (100 IU/kg; RVD+vitamins, n = 7); or control (normal, n = 7). Renal tissue was studied ex vivo using immunoblotting and immunohistochemistry. Basal renal blood flow (RBF) and glomerular filtration rate were similarly decreased in all RVD groups. ACh-stimulated RBF remained unchanged in RVD, increased in RVD+tempol, but further increased (similarly to normal) in RVD+vitamins ( P < 0.05 vs. RVD). Furthermore, RVD+vitamins also showed a decreased presence of superoxide anion, decreased NAD(P)H-oxidase and nitrotyrosine expression, increased endothelial nitric oxide synthase expression, and attenuated renal fibrosis. Chronic antioxidant intervention in early RVD improved renal hemodynamic responses more effectively than acute intervention, likely due to increased nitric oxide bioavailability and decreased structural injury. These suggest that chronic tissue changes play an important role in renal compromise mediated by oxidative stress in RVD.
Recorded and Numerical Strong Motion Response of a Base-Isolated Bridge
Authors: Bessason B. , Haflidason E.
Published: May 2004

Since 1983, 12 Icelandic bridges have been base isolated for seismic protection. Lead-rubber bearings have been used in all the cases. The Thjorsa River Bridge, built in 1950 and retrofitted with base isolation in 1991, is instrumented by strong-motion accelerometers. The bridge has one 83-m-long main span and two 12-m-long approach spans. Only the main span, a steel arch truss with concrete deck, is base isolated. In June 2000, two major earthquakes of magnitude 6.6 and 6.5 occurred in South Iceland; the epicenter was close to the Thjorsa River Bridge. In the first earthquake, a peak ground acceleration of 0.53 g was recorded at the bridge site, and in the second earthquake, a peak ground acceleration of 0.84 g was recorded. The Thjorsa River Bridge survived the earthquakes without any serious damage and was open for traffic immediately after the earthquakes.
Displacement Spectra for Long Periods
Authors: Faccioli Ezio , Paolucci Roberto , Rey Julien
Published: May 2004

Using selected sets of high-quality digital strong motion data from different regions (Taiwan, Japan, Italy, and Greece), the salient features of displacement response spectra in the long-period range are illustrated (up to 10 s period) as a function of magnitude, source distance, and site conditions. By means of simple analytical models of displacement waveforms, we have derived analytical expressions for the displacement spectra that provide satisfactory fits to the observations. These expressions also demonstrate that the moment magnitude and distance control the shape of the spectra consistent with the commonly accepted models of the seismic source. Furthermore, we derived from simple physical considerations an analytical expression of the variation of peak ground displacement with magnitude and distance that reasonably fits the observations. The findings of this study are believed to be particularly useful in the formulation of design elastic displacement spectra for seismic codes, and in zoning studies of seismic hazard for long-period structures.
Guide for Shear-Wave-Based Liquefaction Potential Evaluation
Authors: Andrus Ronald D. , Stokoe Kenneth H. , Hsein Juang C.
Published: May 2004

Small-strain shear-wave velocity measurements provide a promising approach to liquefaction potential evaluation. In some cases, where only seismic measurements are possible, it may be the only alternative to the penetration-based approach. Various investigators have developed relationships between shear wave velocity and liquefaction resistance. Successful application of any liquefaction evaluation method requires that procedures used in their development also be used in their application. This paper presents detailed guidelines for applying the procedure described in Andrus and Stokoe that was developed using suggestions from two workshops and following the general format of the Seed-Idriss simplified procedure. Correction factors to velocity and liquefaction resistance for soil aging are suggested. Based on the work by Juang et. al., factors of safety of 1.0, 1.2, and 1.5 correspond to probabilities of liquefaction of about 0.26, 0.16, and 0.08, respectively. Additional field performance data are needed from all soil types, particularly denser and older soil deposits shaken by stronger ground motions, to further validate the recommended procedure.
Selection and Scaling of Ground Motion Time Histories for Structural Design Using Genetic Algorithms
Authors: Naeim Farzad , Alimoradi Arzhang , Pezeshk Shahram
Published: May 2004

This paper presents a new approach to selection of a set of recorded earthquake ground motions that in combination match a given site-specific design spectrum with minimum alteration. The scaling factors applied to selected ground motions are scalar values within the range specified by the user. As a result, the phase and shape of the response spectra of earthquake ground motions are not tampered with. Contrary to the prevailing scaling methods where a preset number of earthquake records (usually between a single component to seven pairs) are selected first and scaled to match the design spectrum next, the proposed method is capable of searching a set consisting of thousands of earthquake records and recommending a desired subset of records that match the target design spectrum. This task is achieved by using a genetic algorithm (GA), which treats the union of 7 records and corresponding scaling factors as a single “individual.” The first generation of individuals may include a population of, for example, 200 records. Then, through processes that mimic mating, natural selection, and mutation, new generations of individuals are produced and the process continues until an optimum individual (seven pairs and scaling factors) is obtained. The procedure is fast and reliable and results in records that match the target spectrum with minimal tampering and the least mean square of deviation from the target spectrum.
Design Algorithm Based on Probabilistic Seismic Demands for Buildings Rehabilitated with Hysteretic Energy-Dissipating Devices
Authors: Torres Marco Antonio , Ruiz Sonia E.
Published: May 2004

A design algorithm based on a probabilistic seismic demand analysis is proposed for the rehabilitation of buildings with hysteretic energy dissipating devices (EDDs). The acceptance conditions imposed are referred to the maximum story drift developed by the building under rehabilitation, and to the maximum ductility demanded by the EDDs. The algorithm is successfully applied to a ten-story three-bay reinforced concrete building that is rehabilitated with steel U-type EDDs.
Real-Time Seismic Monitoring Needs of a Building Owner—and the Solution: A Cooperative Effort
Authors: Çelebi M. , Sanli A. , Sinclair M. , Gallant S. , Radulescu D.
Published: May 2004

A recently implemented advanced seismic monitoring system for a 24-story building facilitates recording of accelerations and computing displacements and drift ratios in near-real time to measure the earthquake performance of the building. The drift ratio is related to the damage condition of the specific building. This system meets the owner's needs for rapid quantitative input to assessments and decisions on post-earthquake occupancy. The system is now successfully working and, in absence of strong shaking to date, is producing low-amplitude data in real time for routine analyses and assessment. Studies of such data to date indicate that the configured monitoring system with its building specific software can be a useful tool in rapid assessment of buildings and other structures following an earthquake. Such systems can be used for health monitoring of a building, for assessing performance-based design and analyses procedures, for long-term assessment of structural characteristics, and for long-term damage detection.
Seismic Vulnerability of Ancient Churches: I. Damage Assessment and Emergency Planning
Authors: Lagomarsino Sergio , Podestà Stefano
Published: May 2004

This paper describes a new methodology used to assess seismic damage in the churches of Umbria and the Marches, which is based on 18 indicators, each representative of a possible collapse mechanism for a macroelement. The subdivision of the church into macroelements consists of the identification of architectonic elements in which the seismic behavior is almost independent from the rest of the structure (façade, apse, dome, bell tower, etc.). For each macroelement, by considering its typology and connection to the rest of the church, it is possible to identify the damage modes and the collapse mechanisms. During inspection operations, the surveyors must indicate: (a) the actual macroelements; (b) the damage level; and (c) the vulnerability of the church to that mechanism, related to some specific details of construction. From these data a damage score is defined, which is a number from 0 to 1, obtained as a normalized mean of the damage grades in each mechanism. The analysis of the collected data (more than 1,000 churches in Umbria) allows the definition of the correlation between macroseismic intensity and damage.
Seismic Vulnerability of Ancient Churches: II. Statistical Analysis of Surveyed Data and Methods for Risk Analysis
Authors: Lagomarsino Sergio , Podestà Stefano
Published: May 2004

In the context of a seismic prevention strategy, vulnerability analysis has the aim of acquiring knowledge of the buildings in a region, with particular reference to their predisposition to be damaged by an earthquake. The goal may be both at a territorial level, to assess the damage scenario expected after an earthquake of given intensity, and at a detailed level, as a support to the planning of seismic improvement interventions. The latter objective is very important for ancient churches, due to their architectural and historical value. They definitely need a more profound analysis. The survey with the new form proposed in Part I of this paper allows us to highlight the specific vulnerability with regard to the different collapse mechanisms that are typical of earthquakes, taking into account, if present, the damage due to historical events as an observed vulnerability.
Applied Incremental Dynamic Analysis
Authors: Vamvatsikos Dimitrios , Cornell C. Allin
Published: May 2004

We are presenting a practical and detailed example of how to perform incremental dynamic analysis (IDA), interpret the results and apply them to performance-based earthquake engineering. IDA is an emerging analysis method that offers thorough seismic demand and capacity prediction capability by using a series of nonlinear dynamic analyses under a multiply scaled suite of ground motion records. Realization of its opportunities requires several steps and the use of innovative techniques at each one of them. Using a nine-story steel moment-resisting frame with fracturing connections as a test bed, the reader is guided through each step of IDA: (1) choosing suitable ground motion intensity measures and representative damage measures, (2) using appropriate algorithms to select the record scaling, (3) employing proper interpolation and (4) summarization techniques for multiple records to estimate the probability distribution of the structural demand given the seismic intensity, and (5) defining limit-states, such as the dynamic global system instability, to calculate the corresponding capacities. Finally, (6) the results can be used to gain intuition for the structural behavior, highlighting the connection between the static pushover (SPO) and the dynamic response, or (7) they can be integrated with conventional probabilistic seismic hazard analysis (PSHA) to estimate mean annual frequencies of limit-state exceedance. Building upon this detailed example based on the nine-story structure, a complete commentary is provided, discussing the choices that are available to the user, and showing their implications for each step of the IDA.
Multielement Profiling Analyses of Biological, Geochemical, and Environmental Samples as Studied by Analytical Atomic Spectrometry
Authors: Haraguchi Hiroki
Published: May 2004

The progress of modern analytical atomic spectrometry is briefly reviewed with emphasis on ICP-AES and ICP-MS; these provide some excellent analytical features such as high sensitivity, wide linear dynamic range, and multielement detection capability. Thus, the multielement determination of the major-to-ultratrace elements from % to sub-ppt (1 ppt = 10−12 g ml−1) level is possible for the biological, geochemical, and environmental samples. The standard or certified reference materials of plant, human blood serum, and the other biological samples were analyzed to establish the reliable analytical methods for the multielement determination by ICP-AES and ICP-MS. The modern analytical methods were applied to: (i) the correlation analysis of the elements in human blood serum, and (ii) the determination of rare earth elements in human blood serum on a personal basis. The speciation of trace elements in natural water was also carried out by the SEC (size exclusion chromatography)/UV absorption detection/ICP-MS combined system after ultrafiltration of the water samples. The SEC chromatograms indicated that most of trace elements in natural water existed as large organic molecule–metal complexes with the molecular weight of > 300000 and 10000—50000. In addition, trace elements in man and in the sea were discussed from the viewpoints of the geochemical classification of the elements on the earth, the Lewis’s acid-base theory, and the principle of HSAB (hard and soft acids and bases). Such multielement information allows the multielement profiling analyses of various samples to elucidate the elemental distributions, physicochemical characteristics, and behaviors of the major-to-ultratrace elements in relation with the biological functions or with the geochemical and environmental phenomena.
Thermodynamic Interactions in Binary Mixtures of Styrene with n-Alkanes at 298.15 K
Authors: Aminabhavi Tejraj M , Patil Virupakshagouda B , Banerjee Kamalika , Balundgi Ramachandra H
Published: May 2004

Thermodynamic interactions in binary mixtures of styrene with n-alkanes have been studied in terms of excess quantities using the experimental results of density, viscosity, and speed of sound at 298.15 K. Flory as well as Prigogine–Flory–Patterson equations were used to calculate the excess molar volume in addition to enthalpy, entropy, and free-energy mixing functions. The viscosity results were analysed using Bloomfield and Dewan theory to predict viscosity deviations, while the speed-of-sound results were analysed by Benson and Kiyohara theory to predict the deviations in isentropic compressibility. The Prigogine–Saraga theory was used to calculate the deviations in internal pressure of liquids and liquid mixtures. Furthermore, isothermal compressibility values were predicted from the Flory equation of state and compared with the experimentally obtained values. Overall, the computed and experimental results are discussed in terms of thermodynamic interactions between the mixing components.
Side Chain Dynamics in Poly(ethyl acrylate) Studied by Molecular Dynamics Simulation
Authors: Kikuchi Hiroaki , Seki Kazuhiko , Kuwajima Satoru , Okui Norimasa
Published: May 2004

A molecular dynamics (MD) trajectory of 1.0 ns duration has been computed for a methyl-terminated atactic poly(ethyl acrylate) using force field parameters which we determined by ab initio molecular-orbital calculations for small molecules (RHF/6-31G level). Local side chain motions were clarified by analyses of the MD trajectory. The torsional angle autocorrelation functions (TACF) were calculated for each dihedral angle in the side chain. All of the TACF were strongly non-exponential. The entire side chain rotation was an asymmetric 180° jump motion with a rapid torsional oscillation within stable and metastable conformations, while ethyl group motion around the O(non-carbonyl)–CH2 bond in the side chain was characterized by rapid torsional motion in the angle range from 60 to 300°involving an obscure three-site jump motion.
High-Resolution Frequency Analysis by the Use of Derivatives of the Fourier Transform: Application to Fluorescence Quantum Beats
Authors: Kono Hirohiko , Kawata Isao , Ohta Nobuhiro
Published: May 2004

The v th frequency derivative of the Fourier spectrum obtained by the use of tv-windows is proposed with some applications to practical examples. Derivative power spectra have higher resolution and lower base lines than conventional spectra (e.g., v = 0), and are insensitive to the choice of the beginning of the acquisition duration. For extremely large v, the spectrum is not resolved well. The optimal value of v is determined so that the main body of the product of the window tv and the signal is accommodated in the range where the S/N ratio is relatively high. This criterion is successfully applied to a signal generated from a known spectrum and to fluorescence quantum beats in pyrimidine at zero and nonzero magnetic fields.
Fluorescence and FTIR Studies on the pH-Dependent Conformational Change of Poly(methacrylic acid) in Aqueous Solutions
Authors: Nakashima Kenichi , Fujimoto Yoshinori , Anzai Takayuki , Dong Jian , Sato Hidetoshi , Ozaki Yukihiro
Published: May 2004

Fluorescence and FTIR spectroscopy have been used to investigate the pH-dependent conformational change of poly(methacrylic acid) (PMA) in aqueous solutions. Fluorescence intensity and lifetime, and other fluorescence parameters of the 1-pyrenemethanol probe were measured as a function of pH in PMA aqueous solutions. The fluorescence data obtained show that PMA undergoes a sharp coiling ↔ uncoiling change around pH 5. FTIR spectra of PMA were successfully observed by an attenuated total reflection technique. The FTIR data show that the carboxyl groups of PMA are ionized progressively over the wide pH range from 3 to 8, and that PMA takes an expanded conformation under basic conditions. These results make it clear that although the ionization of the carboxyl groups takes place progressively, the conformational change of PMA is brought about abruptly.
Hydrophobic Interaction of mer-Tris(α-amino acidato)cobalt(III) with Tetrabutylammonium Ion
Authors: Yoshimura Yasuki
Published: May 2004

An interaction of NaBr, NH4Br, Me4NBr, Et4NBr, Pr4NBr, Bu4NBr, and NaBPh4 with mer-(+)-tris(l-alaninato)cobalt(III) (mer-(+)-[Co(l-ala)3]) was examined by estimating the standard enthalpy (ΔHtr°) and entropy of transfer (ΔStr°) of mer-(+)-[Co(l-ala)3] from water to the salt solutions on the basis of the temperature dependence of solubility. A difference in correlation between ΔHtr° and TΔStr° demonstrated that while NaBr and NH4NBr increase the solubility of mer-(+)-[Co(l-ala)3] by hydrophilic interaction, Pr4NBr, Bu4NBr, and NaBPh4 increase the solubility of mer-(+)-[Co(l-ala)3] by hydrophobic interaction. On the basis of this finding, ΔHtr° and TΔStr° of the transfer from water to aqueous Bu4NBr solution for the mer-tris(aniono)cobalt(III) of glycine (glyH), l-alanine (alaH), l-serine (serH), Dl-2-aminobutylic acid (abaH), Dl-norvaline (nvalH), l-valine (valH), and l-leucine (leuH) led to the conclusion that hydrophobicity of the amino acids increases in the order of glyH < serH < alaH < abaH < nvalH < valH < leuH. This conclusion is compared with the hydrophobicity order reported in the literature.
Kinetics and Mechanism of the Oxidation of [Fe(CN)6]4− to [Fe(CN)6]3−, Induced by the Reaction between Cu2+ and I− in Aqueous Solution. Oxidation Reaction by a Radical Anion I2−·
Authors: Kimura Masaru , Shiota Yuko , Kishi Shinobu , Tsukahara Keiichi
Published: May 2004

The hexacyanoferrate(II) ion ([Fe(CN)6]4−) was rapidly oxidized to [Fe(CN)6]3− by a radical anion, I2−·, which was formed by a reaction between the copper(II) ion and the iodide ion. The oxidation reaction was accelerated by increasing the pH. Under the conditions of lower pH’s, the [Fe(CN)6]3− acted as a retarder to the oxidation reaction. The mechanisms for such reactions are discussed in terms of accounting for the obtained results.
Artificial Control of Enzyme Reactions by the Photoexcitation of Hematoporphyrin Adsorbed on Living Yeast Cells
Authors: Noda Hiroyuki , Ohya Hiroaki , Kamada Hitoshi
Published: May 2004

The objective of our research was to establish control of biological functions by the illumination of a photosensitizer of hematoporphyrin that was externally provided in a biological system. We found using an ESR method that the reduction of 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPOL), as a reduction probe, caused by enzyme reactions can be controlled through the photoexcitation of hematoporphyrin adsorbed on the living yeast cells (HP/Yeast system). On the basis of the effects of some electron-transfer blockers through its reduction rate, it has been postulated that the reduction of TEMPOL is mainly conducted through ferredoxin (ferredoxin-NAD(P)+ reductase), which could be controlled through the illumination of HP connected with a mitochondrial electron-transfer system. A possible mechanism for controlling the reduction of TEMPOL is discussed in connection with the energy levels of HP and the redox potentials of the components in yeast cell participating in this phenomenon.
Iron(II)-Assisted Assembly of Trivalent GalNAc Clusters and Their Interactions with GalNAc-Specific Lectins
Authors: Sakai Shin , Shigemasa Yoshihiro , Sasaki Tomikazu
Published: May 2004

A novel metal-assisted assembly of mulitivalent carbohydrate ligands is described. A bipyridine-modified N-acetylgalactosamine (bipy-GalNAc) undergoes Fe(II)-induced self-association to form a trimeric GalNAc ligand (FeII(bipy-GalNAc)3). The synthetic GalNAc cluster strongly binds to Vicia villosa B4 lectin and Glycin Max lectin, which recognizes multiple GalNAc residues. The trimeric GalNAc ligand is formed as a mixture of four diastereomeric isomers: Δ-fac, Λ-fac, Δ-mer, and Λ-mer. These stereoisomers are in a dynamic equilibrium at room temperature. The equilibrium allows the spatial arrangement of the three GalNAc residues to change in order to fit into a multivalent carbohydrate binding site of the lectins. Detailed analysis of the kinetic and thermodynamic data for the isomerization can provide structural information of the carbohydrate binding site of the lectins.
Effects of Metal Salts on the Structure and Activity of α-Chymotrypsin in Ethanol/Water
Authors: Sasaki Toshiya , Kise Hideo
Published: May 2004

The catalytic activity and circular dichroic (CD) spectra of α-chymotrypsin (CT) were measured in ethanol/water (95/5, v/v) solution containing small amounts of metal salts. Although the catalytic activity of CT increased upon the addition of all the metal salts used, the magnitude of activity increase was different for different metal salts. Especially, calcium acetate accelerated the transesterification of amino acid up to 6 fold at 100 μM. The secondary and tertiary structures of CT were also changed by metal salts, as studied by CD measurements. The effects of metal salts on the stability of CT in ethanol/water were also studied, and it was found that the residual activity of CT after 7 days in ethanol/water in the presence of Ca(OCOCH3)2 was about 20% of the initial activity. The change in activity was closely correlated with the change in the mean residue ellipticity of CT at 208 or 230 nm.
Preparation and Properties of Stabilized Thioxophosphine Sulfides Bearing the 4-t-Butyl-2,6-bis(dialkylaminomethyl)phenyl or the 2,4-Di-t-butyl-6-(dialkylaminomethyl)phenyl Substituents
Authors: Kamijo Kazunori , Otoguro Akihiko , Toyota Kozo , Yoshifuji Masaaki
Published: May 2004

Stabilized thioxophosphine sulfides bearing the 4-t-butyl-2,6-bis(dialkylaminomethyl)phenyl or the 2,4-di-t-butyl-6-(dialkylaminomethyl)phenyl group, as well as their 15N labeled analogs, were prepared. Intramolecular interaction between the nitrogen and the phosphorus atoms was investigated, mainly by means of 31P NMR and 1H NMR spectroscopic studies.
Re-investigation of the Coupling Reaction of 2-Aryl-1,1-dibromo-3,3,3-trifluoropropenes. Preparation of Perfluoroalkylated [3]Cumulenes
Authors: Uno Hidemitsu , Nibu Nobumasa , Misobe Noboru
Published: May 2004

The coupling reaction of perfluoroalkylated 2-aryl-1,1-dibromoalkenes using zinc and copper(I) bromide gave stereoisomeric mixtures of [3]cumulenes and [4]radialenes. The ratio of [3]cumulenes and [4]radialenes mainly depended upon the reaction temperature and the electronic character of the aryl group. When the coupling reaction was carried out at −40 °C, (E)- and (Z)-[3]cumulenes were obtained in good selectivity and only trace amounts of [4]radialenes were detected by a 19F NMR analysis. On the other hand, a similar reaction at −60 °C afforded a considerable amount of [4]radialene isomers. When the cis-[3]cumulenes were heated at an appropriate temperature, selective isomerization to trans-[3]cumulenes occurred.
A Divergent Synthesis of Lipid A and Its Chemically Stable Unnatural Analogues
Authors: Liu Wen-Chi , Oikawa Masato , Fukase Koichi , Suda Yasuo , Kusumoto Shoichi
Published: May 2004

Lipid A and its two chemically stable analogues, wherein the glycosidic phosphoryl groups in lipid A is replaced with 2-(phosphonooxy)ethyl or carboxymethyl groups, have been synthesized by an improved and divergent route via a common allyl glycoside intermediate in which the 4-hydroxy group was protected as a benzyl ether. The total yields were more than 20% for 11 or 12 steps starting from allyl 4,6-O-benzylidene-2-deoxy-2-(trichloroethoxycarbonylamino)-d-glucopyranoside. These synthetic chemically stable analogues induce interleukin-6 and tumor necrosis factor α in human peripheral whole blood cells with potencies comparable to those by natural-type synthetic lipid A. The Limulus activities of both analogues were found to be even stronger than the activity of the natural-type one.
Oxidation Behavior of Ni in Molten Carbonate
Authors: Motohira Naobumi , Takai Takahiro , Kamiya Nobuyuki , Ota Ken-ichiro
Published: May 2004

The oxidation behavior of Ni in molten carbonate was evaluated by chronopotentiometry. The oxidation of Ni in molten carbonate proceeded in a two-step reaction. The first step of oxidation was independent of the specimens’ nature and depended on PCO2. On the other hand, the second step of oxidation depended on the batch of the specimens, and was independent of PCO2. The corrosion product in both oxidation processes was divalent Ni oxide, namely NiO.
Synthesis of Enantiomerically Pure (R,R)- and (S,S)-1,2-Bis(pentafluorophenyl)ethane-1,2-diamine and Evaluation of the pKa Value by Ab Initio Calculations
Authors: Sakai Takashi , Korenaga Toshinobu , Washio Noriyuki , Nishio Yuji , Minami Shinichi , Ema Tadashi
Published: May 2004

1,2-Bis(pentafluorophenyl)ethane-1,2-diamine (1) was synthesized by the imino pinacol coupling of 4-methoxy-N-(pentafluorobenzylidene)benzylamine using a Zn–Cu couple and p-TsOH·H2O. The optical resolution of (±)-1 by means of chiral HPLC gave enantiomerically pure (R,R)- and (S,S)-1. The pKa value of 1 was estimated by a titration experiment and ab initio calculations, showing that 1 has a basicity comparable to aniline derivatives.
The Cyanation of Aromatic Halides Catalyzed by Nickel(0) Complexes Generated In Situ. III. Kinetic and Mechanistic Aspects
Authors: Sakakibara Yasumasa , Sasaki Ken , Okuda Fumio , Hokimoto Akihiro , Ueda Takuji , Sakai Mutsuji , Takagi Kentaro
Published: May 2004

The cyanation of chlorobenzene catalyzed by [Ni(PPh3)n], which was generated in situ from [NiBr2(PPh3)2]–Zn–PPh3 (Ni:Zn:P = 1:3:2 molar ratio), was carried out at 60 °C using KCN or NaCN in hexamethyl phosphoric triamide (HMPA). Kinetic analyses revealed that the reaction rates in the KCN–HMPA system were zero order for both of chlorobenzene and nickel concentrations, and two-thirds order for KCN. The determination of the kinetic order for NaCN was difficult due to its high solubility in HMPA since excess cyanide ion inhibited the reaction. Zinc bromide which was formed with [Ni(PPh3)n] from [NiBr2(PPh3)2]–Zn–PPh3, acted as an important cocatalyst for the successful cyanation by comparison with [Ni(cod)2] (cod = 1,5-cyclooctadiene)–PPh3 system. Based on these experimental results, a reaction mechanism was proposed and discussed.
Development of New Reagents Containing Silicon and Related Metals and Application to Practical Organic Syntheses
Authors: Hosomi Akira , Miura Katsukiyo
Published: May 2004

Our research works in the last few decades are summarized. We have studied the synthetic use of organometallics, especially organosilicon compounds, and have developed a number of new reagents and reactions useful for efficient organic synthesis. In the first section, the allylation of carbon electrophiles with allylsilanes, the so-called Hosomi–Sakurai reaction, is described. We have demonstrated that the allylation reaction is valuable not only for highly regio- and stereoselective carbon–carbon bond formation but also for introduction of a variety of functionalities. The second section deals with synthetic reactions using highly coordinated organosilanes and other organometallics, including Cr, Mn, Fe, and Cu. Higher coordination by one or more extra anionic ligands brings about unique reactivities that enable synthetically useful transformations. As shown in the third section, we developed stable 1,3-dipole equivalents protected by a silyl group and their cycloadditions, leading to N, S, or O-containing heterocycles. The following section describes the stereoselective synthesis of cyclic ethers and amines by acid-catalyzed cyclizations of vinylsilanes bearing a hydroxy or amino group. These silicon-directed cyclizations have disclosed the synthetic utility of β-silylcarbenium ion species generated from vinylsilanes by protonation. The copper-catalyzed reactions of organosilanes via silicon–copper exchange are described in the fifth section. In the final section, our studies on homolytic carbometalation reactions are presented.
Novel π-Conjugated Nano-Supramolecules Having Fine-Controlled Metal-Assembling Functions
Authors: Higuchi Masayoshi , Yamamoto Kimihisa
Published: May 2004

Dendritic and cyclic polyphenylazomethines (DPA and CPA) were exploited as π-conjugated polymer ligands having novel topological structures. DPAs were synthesized by the convergent method via dehydration in the presence of TiCl4. DPA G4 molecules have a sphere-like structure with a 2.3-nm diameter, and they are regularly assembled without deformation of the molecule on a plate, as observed by means of GPC, molecular modeling, TEM, AFM, and π–A measurements. The stepwise radial complexation in DPAs with SnCl2 was observed as a stepwise shift in the isosbestic point in the UV–vis spectra; this conclusion was further supported by TEM, NMR, and shell-selective reduction (SSR) of the imines. The order of complexation among the shells permits control by the introduction of electron-withdrawing groups to the DPA structure. CPAn-ab and CPAn-aabb (designated as CPAX-Y where X and Y are the degree of polymerization and whether the polymerization was AB- or AABB-type, respectively) was synthesized via dehydration in the presence of TiCl4, TiCl4(THF)2 or p-toluenesulfonic acid (PTS). The unique structures of CPAn-ab and CPAn-aabb: triangle, square, or oblong, and their regular molecular-packing were revealed by NMR, MD calculations, and X-ray crystal analysis. CPAn-aabb shows reversible redox functions by protic acid doping, unlike conventional polyphenylazomethine (PPA).
Exterior Characteristics of Molecular Orbitals and Molecular Surfaces as Studied by Atomic Probes
Authors: Ohno Koichi
Published: May 2004

This is a brief survey of studies on exterior characteristics of molecules conducted by means of atomic probes, mostly by metastable states of rare gas atoms in collisional ionization experiments and partly by atoms from H to Ar in quantum chemical calculations. Spatial distributions of molecular orbitals (MO) outside the molecular surfaces have been studied to determine stereoelectronic properties related with partial ionization cross sections of molecules due to electrophilic attacks of metastable atoms. A newly developed collision-energy/electron-energy resolved two-dimensional electron spectroscopy has disclosed anisotropic and dynamic characteristics of molecular surfaces (MS) via collision-energy dependence of partial ionization cross sections. Starting from a simple theoretical model of exterior electron densities (EED), researchers have developed quantum chemical treatments of the ionization reactions to a level of trajectory calculations based on potential energy surfaces of both entrance and exit reaction channels together with electronic transition rates between the surfaces. The present stage of techniques can elucidate one of the two aspects, MO or MS, assuming knowledge of the other. Since experimental aspects may contain various features of MO and MS, a simultaneous determination of both MO and MS by experiments will allow further developments in experimental techniques.
X-ray Analysis of Excited-State Structures of the Diplatinum Complex Anions in Five Crystals with Different Cations
Authors: Yasuda Nobuhiro , Uekusa Hidehiro , Ohashi Yuji
Published: May 2004

The photo-excited structures of [Pt2(pop)4]4− and [Pt2(pop)2(popH)2]2−, (pop = diphosphite) in five kinds of complexes were analyzed by X-rays. For the complex with tetrabutylammonium (Bu), tetrapentylammonium (Pn), benzyltriethylammonium (Bzte), or benzyltributylammonium (Bztbu) as a counter cation, the Pt complex anion is attached by two protons and is represented as [Pt2(pop)2(popH)2]2−, whereas the anion is [Pt2(pop)4]4− for the complex with benzyldimethylphenylammonium (Bzdmp) as a cation. Since the Bu, Pn, and Bzte complexes have two crystal forms, the structures of eight crystals, Bu1, Bu2, Pn1, Pn2, Bzte1, Bzte2, Bztbu, and Bzdmp, were determined by X-ray analysis before irradiation. The five crystals of Bu1, Pn1, Bzte1, Bztbu, and Bzdmp were irradiated with a xenon lamp. The intensity data were collected at the light-on and light-off stages at 173 K for Bu1, Pn1, and Bzdmp crystals and at 103 K for Bzte1 and Bztbu crystals. Each crystal showed the contraction of the unit-cell volume significantly at light-on stage and returns to the original one at light-off stage. The analyzed structures at light-on and light-off stages clearly indicated that the Pt–Pt and Pt–P bond distances became significantly shorter at light-on stage than the corresponding distances at light-off stage. The decreased values for the Pt–Pt and Pt–P distances at the light-on stage are 0.0038(3) and 0.0069(10) Å for Bu1, 0.0081(3) and 0.0053(11) Å for Pn1, 0.0127(5) and 0.0085(14) Å for Bzte1, 0.0031(3) and 0.0019(12) Å for Bztbu, and 0.0019(2) and 0.0033(8) Å for Bzdmp, respectively. The other bond distances in anions and cations are not significantly changed. These structural changes indicate that the excited- and ground-state molecules reach the equilibrium state at the light-on stage; the values are in good agreement with the results observed by spectroscopic methods and theoretical calculation.
One Novel Racemic Cu–Co Cyano-Bridged Complex: Synthesis, Characterization, Crystal Structure, and Magnetic Properties
Authors: Choudhury Chirantan Roy , Dey Subrata Kumar , Mitra Samiran , Mondal Nijhuma , Ribas Joan , Abdul Malik K M
Published: May 2004

One novel racemic Cu–Co cyano-bridged complex [C38H38CoCu2N14O]+[C22H18CoCuN10]−·7H2O where [L = N,N′-bis(2-pyridylmethylene)butane-1,4-diamine] has been prepared and characterized by elemental analyses, spectroscopic study, single crystal X-ray crystallography, and variable temperature magnetic susceptibility measurements. The compound crystallises as a 57/43 racemic twin and contains two different, one binuclear and one trinuclear, complex species. A low temperature magnetic susceptibility measurement showed the existence of very weak antiferromagnetic interactions.
New Bioactive Zinc(II) Complexes with Peptides and Their Derivatives: Synthesis, Structure, and In Vitro Insulinomimetic Activity
Authors: Ueda Eriko , Yoshikawa Yutaka , Kishimoto Noriko , Tadokoro Makoto , Sakurai Hiromu , Kajiwara Naemi , Kojima Yoshitane
Published: May 2004

Four Zn(II) complexes with dipeptides and three new Zn(II) complexes with pseudo-tripeptides were prepared and a complex, [Zn(glythr)2]n, was revealed to have a polymeric structure by X-ray structure analysis. The ligand, glythr−, acts as a bridging ligand completely, a monodentate oxygen atom of the terminal carboxyl group of threonine residue and a didentate ligand containing the nitrogen and oxygen atoms of glycine one. Because the Zn2+ ion has a distorted six-coordinated octahedral geometry, it binds with two terminal carboxyl groups and two didentate ligands. Also, all Zn(II) complexes were found to have high in vitro insulinomimetic activity compared with that of zinc sulfate, as estimated by the inhibition of free fatty acid release in isolated rat adipocytes that had been treated with epinephrine (adrenalin).
A New Method for 18F-Labeling of Biochemical Molecules Using [18F]Perfluoronitrobenzene and Its Application to 18F-Labeling of Angiotensin II
Authors: Hashizume Kazunari , Tamakawa Hiroyoshi , Hashimoto Naoto , Miyake Yoshihiro
Published: May 2004

We propose a new method for labeling biochemical molecules with fluorine-18 (positron emitters) using [G-18F]polyfluoronitrobenzene as the reagent. Perfluoronitrobenzene was easily labeled with 18F− by the 18F- for-19F exchange reaction giving [G-18F]pentafluoronitrobenzene (PFNB, radiochemical yield 30-41 %) and the [G-18F]PFNB was applied successfully for 18F-labeling of angiotensin II.
Chelate-Ring Formation in Cr(CO)5(phen) Studied by Laser Flash Photolysis with Visible and Infrared Detection
Authors: Oishi Shigero , Inui Hiroshi , Kuriyama Yasunao
Published: May 2004

Kinetic parameters were obtained for the formation of chelate ring in transient Cr(CO)5(phen) and 0.17 s−1 (20 °C), ΔH‡ = 85.0 kJ·mol−1, and ΔS‡ =29.8 J·mol−1·K−1, indicating the concerted extrusion of CO by an uncoordinated nitrogen rather than the simple dissociation of CO. In comparison with other bidentate ligands, it was revealed that the structural advantage of phen, which gave significant enhancement in the rate of chelation, was due to entropy term.
Enantioselective Synthesis of Octalactin A
Authors: Kodama Mitsuaki , Matsushita Masayuki , Terada Yuuko , Takeuchi Atsuko , Yoshio Suzuyo , Fukuyama Yoshiyasu
Published: May 2004

An efficient enantioselective synthesis of the C1-C9 fragment 2 of octalactin A (1) has been achieved starting from (−)-citronellol (3).
An Efficient Method for Catalytic and Stereoselective Glycosylation with Thioglycosides Promoted by Trityl Tetrakis(pentafluorophenyl)borate and Sodium Periodate
Authors: Uchiro Hiromi , Mukaiyama Teruaki
Published: May 2004

A new and efficient method for catalytic stereoselecive synthesis of several glycosides from thioglycosides is successfully performed by the combined use of trityl salt and sodium periodate. Several β-d-gluco- and galactopyranosides are prepared in good yields with high stereoselectivities.
A Carbene•Phosphinidene Adduct: “Phosphaalkene”
Authors: Arduengo Anthony J , Dias H V Rasika , Calabrese Joseph C
Published: May 2004

The synthesis, characterization and X-ray crystallographic structure determination are described for a “phosphaalkene” formally derived from 1,3,4,5-tetramethylimidazol-2-ylidene and phenylphosphinidene. This carbene•phosphinidene adduct has a central P-C bond length of 179.4 pm and a dihedral twist of 46° which indicates a very weak C-P pπ-pπ interaction. The valence angle at phosphorus in 102.3°.
Preparation and Characterization of Macrocyclic Tetraamine Dimethylthiolate Copper(II) Complex
Authors: Choi Ki-Young , Oh Mi-Ran , Suh Il-Hwan
Published: May 2004

A novel compound, [Cu(L)(SCH3)2]· 2H2O 1 (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07,12]docosane), bridged by two thiolate sulfur atoms, has been prepared and characterized. The copper(II) ion adopts a tetragonally elongated octahedral geometry with two axial thiolate sulfur atoms.
The Influence of Fluorinated Alkyl Chains on the Stabilization of Hydrogen Bonded Liquid Crystals
Authors: Bernhardt Henry , Weissflog Wolfgang , Kresse Horst
Published: May 2004

Perfluorinated alkyl chains were introduced into hydrogen bonded associates. Both, mesophase induction and stabilization were observed.
13C-NMR Evidence for Hydrogen Supply by Water for Polymer Cracking in Supercritical Water
Authors: Nakahara Masaru , Tennoh Toshinari , Wakai Chihiro , Fujita Emi , Enomoto Heiji
Published: May 2004

A rubber polymer (EPDM, ethylene-propylene-diene-terpolymer) vulcanized was cracked to paraffinic oil (PO) in NaOH-containing supercritical water (SCW) at 420 °C and 30 MPa. The SCW polymer cracking in not oxidative but reductive. The 13C-NMR analysis of PO obtained by SCW D2O cracking demonstrates that the terminal methyl carbons are deuterated as a clear indication of hydrogen supply by SCW in the cracking.
Stereoselective Synthesis of trans-2,5-Disubstituted Tetrahydrofurans via the Lewis Acid Mediated Reduction of Cyclic Hemiketals with Triphenylsilane
Authors: Nishiyama Yutaka , Tujino Takashi , Yamano Tadamichi , Hayashishita Masayoshi , Itoh Kazuyoshi
Published: May 2004

An efficient method for the synthesis of trans-2,5-disubstituted tetrahydrofuran derivatives has been developed. Dithioacetal-functionalized cyclic hemiketals are reduced by triphenylsilane (Ph3SiH) in the presence of TiCl4 to afford the corresponding trans-2,5-disubstituted tetrahydrofuran derivatives in good yield and high stereoselectivity. Asymmetrical synthesis of (2S,5S) disubstituted tetrahydrofuran was also achieved by using this reduction method.
Carbon Molecular Sieve Membrane Prepared from Phenolic Resin
Authors: Kita Hidetoshi , Maeda Hiroshi , Tanaka Kazuhiro , Okamoto Ken-ichi
Published: May 2004

Carbon membranes are prepared by coating thin layers of phenolic resin on the outer surface of a porous alumina substrate and then carbonizing the polymer under nitrogen atmosphere at 600 °C. The membranes have excellent separation performances of alkene/alkane and CO2/N2.
Linear Trinuclear Copper(II) Complexes Bridged by Oximato and Azido or Hydroxo Groups
Authors: Akagi Fumio , Nakao Yasuo , Matsumoto Keiji , Takamizawa Satoshi , Mori Wasuke , Suzuki Shinnichiro
Published: May 2004

The linear trinuclear copper(II) complexes Cu3(L1)2(N3)2(NO3)2·2H2O·2CH3OH 1 and Cu3(L1)2(OH)2(ClO4)2  2 containing 3-[{2-(2-pyridinyl)ethyl}imino]-2-butanone oximato ligand (L1) were prepared; the crystal structure of 1 was determined by X-ray crystallography. Magnetic susceptibility measurements from liquid helium temperature to room temperature showed a vary strong antiferromagnetic exchange coupling between copper(II) ions(J = −266 cm−1 and −245 cm−1 for 1 and 2, respectively, H=−2JS1·S2).
Regioselective distal-Dibromination of Calix[4]resorcinarene
Authors: Konishi Hisatoshi , Nakamaru Hidekazu , Nakatani Hideki , Ueyama Tsuyoshi , Kobayashi Kazuhiro , Morikawa Osamu
Published: May 2004

The partial bromination of calix[4]resorcinarene with a limited amount of N-bromosuccinimide was examined. The ratio of the two dibromo derivatives, distal- and proximal-isomers, was 10:1, which is much different from the statistical value of 1:2. The simple procedure for the preparation of the distal-dibromo derivative is described.
A Novel Type of Amidato Coordination: The Metallocycle Rh-Rh-NH-C(Me)=O
Authors: Kukushkin Vadim Yu , Nishioka Takanori , Nakamura Shigeyuki , Kinoshita Isamu , Isobe Kiyoshi
Published: May 2004

Treatment of [Rh2Cp*2(μ-CH2)2(μ-O2CO)] (Cp* = η5-C5Me5) with acetonitrile in aqueous solution followd by addition of KPF6 affords the Rh–Rh complex [Rh2Cp*2(μ-CH2)2(μ-NHC(=O)Me)][PF6], which has been characterized by elemental analysis, FAB-MS, 1H and 13C{1H} NMR spectroscopy, and X-ray crystallography. [Rh2Cp*2(μ-CH2)2(μ-η1:η1-NHC(=O)Me)][PF6] is the first example of an amidato complex where the ligand [NHC(=O)Me]− links the metal–metal site forming a novel type of metallocycle.
Femtosecond Visible Pump Mid-IR Probe Study on the Effects of Surface Treatments on Ultrafast Photogenerated Carrier Dynamics in n-GaAs (100) Crystals
Authors: Ebina Kojiro , Yagi Ichizo , Noguchi Hidenori , Uosaki Kohei
Published: May 2004

The femtosecond visible pump mid-IR probe technique was employed to investigate photogenerated carrier dynamics in n-GaAs (100) crystals subjected to various surface treatments in a time domain of picoseconds–several tens of picoseconds. Pt- or Ru-treatment significantly accelerated the carrier recombination as a result of the introduction of surface states. The recombination rate was also increased by Au-treatment but less significantly than that by the Pt- or Ru-treatment. The effect of sulfide treatment on the recombination dynamics seemed to be rather small, although it has been reported that the density of surface states is decreased by the sulfide treatment.