bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical modeling of biomedical corpora: mining the Caenorhabditis Genetic Center Bibliography for genes related to life span
Authors: Blei DM , Franks K , Jordan MI , Mian IS
Published: May 2006

Background

The statistical modeling of biomedical corpora could yield integrated, coarse-to-fine views of biological phenomena that complement discoveries made from analysis of molecular sequence and profiling data. Here, the potential of such modeling is demonstrated by examining the 5,225 free-text items in the Caenorhabditis Genetic Center (CGC) Bibliography using techniques from statistical information retrieval. Items in the CGC biomedical text corpus were modeled using the Latent Dirichlet Allocation (LDA) model. LDA is a hierarchical Bayesian model which represents a document as a random mixture over latent topics; each topic is characterized by a distribution over words.

Results

An LDA model estimated from CGC items had better predictive performance than two standard models (unigram and mixture of unigrams) trained using the same data. To illustrate the practical utility of LDA models of biomedical corpora, a trained CGC LDA model was used for a retrospective study of nematode genes known to be associated with life span modification. Corpus-, document-, and word-level LDA parameters were combined with terms from the Gene Ontology to enhance the explanatory value of the CGC LDA model, and to suggest additional candidates for age-related genes. A novel, pairwise document similarity measure based on the posterior distribution on the topic simplex was formulated and used to search the CGC database for "homologs" of a "query" document discussing the life span-modifying clk-2 gene. Inspection of these document homologs enabled and facilitated the production of hypotheses about the function and role of clk-2.

Conclusion

Like other graphical models for genetic, genomic and other types of biological data, LDA provides a method for extracting unanticipated insights and generating predictions amenable to subsequent experimental validation.
Regularized binormal ROC method in disease classification using microarray data
Authors: Ma Shuangge , Song Xiao , Huang Jian
Published: May 2006

Background

An important application of microarrays is to discover genomic biomarkers, among tens of thousands of genes assayed, for disease diagnosis and prognosis. Thus it is of interest to develop efficient statistical methods that can simultaneously identify important biomarkers from such high-throughput genomic data and construct appropriate classification rules. It is also of interest to develop methods for evaluation of classification performance and ranking of identified biomarkers.

Results

The ROC (receiver operating characteristic) technique has been widely used in disease classification with low dimensional biomarkers. Compared with the empirical ROC approach, the binormal ROC is computationally more affordable and robust in small sample size cases. We propose using the binormal AUC (area under the ROC curve) as the objective function for two-sample classification, and the scaled threshold gradient directed regularization method for regularized estimation and biomarker selection. Tuning parameter selection is based onV-fold cross validation. We develop Monte Carlo based methods for evaluating the stability of individual biomarkers and overall prediction performance. Extensive simulation studies show that the proposed approach can generate parsimonious models with excellent classification and prediction performance, under most simulated scenarios including model mis-specification. Application of the method to two cancer studies shows that the identified genes are reasonably stable with satisfactory prediction performance and biologically sound implications. The overall classification performance is satisfactory, with small classification errors and large AUCs.

Conclusion

In comparison to existing methods, the proposed approach is computationally more affordable without losing the optimality possessed by the standard ROC method.
T-cell lymphoproliferative disorder of hand-mirror cell morphology presenting in an eosinophilic loculated peritoneal effusion, with omental "caking"
Authors: Siderits Richard , Godyn Janusz , Tufankjian Dearon , Ouattara Osman
Published: May 2006

Background:

Cells with hand mirror morphology have not, to the best of our knowledge, been described in a primary effusion sample. This paper describes a case of T-cell lymphoma with eosinophilia in a patient with suspected peritoneal carcinomatosis. Rarely, a T-cell lymphoproliferative process may mimic primary peritoneal carcinomatosis, clinically suggested by a presentation in CT imaging of omental caking with bilateral massive loculated effusions in a patient without lymphadenopathy or splenomegaly.

Methods:

A 60 year old caucasian male presented with vague abdominal discomfort and increasing abdominal girth. Computed tomography showed a two centimeter thick omental cake and a small loculated effusion. The clinical presentation and imaging findings were most consistent with peritoneal carcinomatosis. Cytologic evaluation of the effusion was undertaken for diagnostic study.

Results:

Rapid intraprocedural interpretation of the effusion sample showed a monomorphic population of cells with hand-mirror cell morphology exhibiting cytoplasmic extensions (uropodia) with 3-5 course dark cytoplasmic granules and a rim of vacuolated cytoplasm capping the opposing mirror head side. These cells were seen within a background of mature eosinophils. Flow cytometric evaluation of the ascites fluid demonstrated an atypical T-cell population with the following immunophenotype: CD2-, CD3+, CD4-, CD5-, CD7-, CD8+, CD56+. T-cell receptor (TCR) gene rearrangement was positive for clonal TCR-gamma gene rearrangement, supporting the diagnosis of a T-lymphoprolifereative disorder.

Conclusion:

A T-cell lymphoproliferative process may present with hand mirror morphology in an effusion sample. These cells may show polar cytoplasmic vacuolization and 3-5 course granules within the handle of these unique cells. Cytoplasm shows peripheral constriction around the nucleus.
Topoisomerase IIα Gene Amplification Predicts Favorable Treatment Response to Tailored and Dose-Escalated Anthracycline-Based Adjuvant Chemotherapy in HER-2/neu–Amplified Breast Cancer: Scandinavian Breast Group Trial 9401
Authors: Tanner Minna , Isola Jorma , Wiklund Tom , Erikstein Björn , Kellokumpu-Lehtinen Pirkko , Malmström Per , Wilking Nils , Nilsson Jonas , Bergh Jonas
Published: May 2006

Purpose

Amplification of the HER-2/neu and topoisomerase IIα (TOP2A) genes has been linked to the effects of anthracyclines. Their role in predicting the outcome of anthracycline-based adjuvant chemotherapy for breast cancer patients has remained controversial.

Patients and Methods

The present substudy of the Scandinavian Breast Group trial 9401, in which an epirubicin-based regimen (nine courses of tailored and dose-escalated fluorouracil, epirubicin, and cyclophosphamide [FEC]) was compared with three or four courses of standard FEC followed by bone marrow–supported high-dose chemotherapy (cyclophosphamide, thiotepa, and carboplatin), included high-risk breast cancer patients (with eight or more positive axillary lymph nodes or at least five nodes with additional poor prognostic indicators). Amplification of HER-2/neu was determined retrospectively in paraffin-embedded tumor tissue sections by chromogenic in situ hybridization. TOP2A was tested only in HER-2/neu–amplified tumors.

Results

HER-2/neu amplification alone, which was present in 32.7% of the tumors, was a strong prognostic factor for short relapse-free (P = .0034) and overall survival (P = .0008) but showed no direct association with treatment assignment. TOP2A coamplification, which was present in 37% of HER-2/neu–amplified tumors, was associated with better relapse-free survival in patients treated with tailored and dose-escalated FEC (hazard ratio [HR] = 0.45; P = .049). A statistical multivariate Cox's regression analysis confirmed the predictive significance of TOP2A coamplification (HR = 0.30; P = .020) in HER-2/neu–amplified tumors. There was no such association in patients with HER-2/neu–amplified tumors without TOP2A gene amplification.

Conclusion

Coamplification of HER-2/neu and TOP2A may define a subgroup of high-risk breast cancer patients who benefit from individually tailored and dose-escalated adjuvant anthracyclines.
On the Biomechanical Stability of Cementless Straight Conical Hip Stems
Authors: Viceconti M , Pancanti A , Varini E , Traina F , Cristofolini L
Published: May 2006

The aim of the present study was to investigation in vitro the effect of deficient bone-implant contact on the primary stability of a straight conical stem. Various possible deficient contact patterns were derived from surgical simulations. The effect of stair climbing loads on the bone-implant micromotion was firstly investigated using a finite element model and then an in vitro test aimed at assessing primary stability. It was found that if the surface features are prevented from biting dense bone in a few small but critical regions, stem primary stability is completely lost. These results suggest that the surface features used in the axisymmetric stem under investigation can be too sensitive to deficient contact conditions, and thus should be augmented with additional antirotational fins. Preliminary tests showed that a stem with the addition of such fins presents good primary stability in all tested conditions.
The Stability of the Femoral Component of a Minimal Invasive Total Hip Replacement System
Authors: Willems M M M , Kooloos J , Gibbons P , Minderhoud N , Weernink T , Verdonschot N
Published: May 2006

In this study, the initial stability of the femoral component of a minimal invasive total hip replacement was biomechanically evaluated during simulated normal walking and chair rising. A 20 mm diameter canal was created in the femoral necks of five fresh frozen human cadaver bones and the femoral heads were resected at the smallest cross-sectional area of the neck. The relatively short, polished, taper-shaped prostheses were cemented centrally in this canal according to a standardized procedure. A servohydraulic testing machine was used to apply dynamic loads to the prosthetic head. Radiostereophotogrammetric analysis was used to measure rotations and translations between the prosthesis and bone. In addition, the reconstructions were loaded until failure in a static, displacement-controlled test. During the dynamic experiments, the femoral necks did not fail and no macroscopical damage was detected. Maximal values were found for normal walking with a mean rotation of about 0.2° and a mean translation of about 120 μm. These motions stabilized during testing. The mean static failure load was 4714 N. The results obtained in this study are promising and warrant further development of this type of minimal invasive hip prosthesis.
Robust Filtering for Systems with Stochastic Non-Linearities and Deterministic Uncertainties
Authors: Wang Zidong , Yang Fuwen , Liu Xiaohui
Published: May 2006

In this paper, the robust finite-horizon filter design problem is considered for a class of discrete time-varying systems with both stochastic non-linearities and deterministic uncertainties. The description of the stochastic non-linearities is quite general, which comprises state-multiplicative noises and random sequences whose powers depend on either the sector-bound non-linear function of the state or the sign of a non-linear function of the state. The norm-bounded parameter uncertainties are allowed to enter both the system and the output matrices. The aim is to design a robust filter that guarantees an optimized upper bound on the state estimation error variance for all stochastic non-linearities and admissible deterministic uncertainties. The existence conditions for the desired robust filters are first derived and the filter parameters are then determined in terms of the solutions to two recursive Ricatti-like difference equations. A numerical simulation example is presented to show the applicability of the proposed method.
Switched control of a vertical/short take-off land aircraft: An application of linear quadratic bumpless transfer
Authors: Turner M. C. , Aouf N , Bates D. G. , Postlethwaite I , Boulet B
Published: May 2006

This paper describes the design of a switching scheme for integrated flight and propulsion control of a vertical/short take-off land (V/STOL) aircraft throughout the hover and transition regions of its flight envelope. The approach adopted makes use of a recently introduced bumpless transfer technique and presents a methodology for switching between multiple controllers while limiting on-line computational overheads. The success of the switching scheme in maintaining desirable flying qualities as the aircraft accelerates from hover to wing-borne flight is demonstrated in non-linear simulation. Simulation results for the switched system clearly show the effectiveness of the bumpless transfer scheme in preserving closed-loop performance during switching.
Model-in-the-Loop Testing
Authors: Plummer A. R.
Published: May 2006

Physical testing is used extensively to characterize mechanical systems. However, in many cases, mathematical models are now available that adequately describe the behaviour of part of the test specimen. Thus, test systems can be conceived which split the specimen into a physical part, and a virtual part, i.e. a real-time computer simulation. This has the potential to enhance convenience and reduce cost. The term ‘model-in-the-loop’ (MiL) has been used in the automotive industry to describe this concept. In this paper, a general framework for MiL system analysis is described. Two detailed examples are given. These concern the integration of numerical aerodynamic and tyre models into car test rigs. In the first case, the analytical results are validated by data from a real system. It is clear that particular demands are placed on the actuation and sensing systems if the numerical and real parts of the specimen are to interact correctly to give a realistic response for the complete system. Acceptable realism is achieved in the case of the aerodynamic model example. However, the results are less satisfactory in the tyre model example where both actuator response and sensor noise are limiting factors.
Sliding Mode Control of Robot Manipulators Based on Sliding Mode Perturbation Observation
Authors: Fei Y. N. , Smith J. S. , Wu Q. H.
Published: May 2006

This paper presents a sliding mode controller based on a sliding mode perturbation observer (SMPO) for the tracking control of robot manipulators. The SMPO is designed to estimate unmeasurable states and system perturbations that involve system non-linearities, disturbances, and unmodelled dynamics. The use of an SMPO allows the linearization of the input/output and the decoupling of the strongly coupled non-linear robot manipulator system merely by the feedback of joint angles, waiving the need for expensive tachometers. The controller design does not need an accurate model of the robot manipulator. Simulation studies are undertaken based on a two-link robot manipulator to evaluate the proposed approach. The simulation results show that the SMPO has more superior tracking control performance, with a wide range of payloads, in comparison with a sliding mode controller designed based on state feedback linearization with full states available.
Velocity Predictions from a Coupled One-Dimensional/Three-Dimensional Computational Fluid Dynamics Simulation Compared with Measurements in the Catalyst System of a Firing Engine
Authors: Benjamin S F , Disdale W , Liu Z , Roberts C A , Zhao H
Published: May 2006

Velocity measurements were made in the catalyst system of a firing engine using a one-component laser Doppler velocimetry system. The 1.4 l engine was operated at 2000 r/min and 88 per cent full-load condition. Velocity pulsations were observed in one of the runners supplying the catalyst and downstream of the catalyst. The velocity pulsations measured downstream of the catalyst enabled the mean velocity profile to be found. Observations were compared with simulations obtained from a coupling of the Star-CD computational fluid dynamics code, which modelled the catalyst as a three-dimensional component, with the Ricardo WAVE one-dimensional engine-cycle simulation code. The velocities in the runners were predicted to fluctuate between –65 m/s and 240 m/s. The observed velocity showed a similar pulse shape but a smaller magnitude of reversed flow. The velocities downstream of the catalyst were predicted to fluctuate between –5 and 22 m/s. The observed velocities showed smaller amplitude pulsations and significantly lower magnitudes of reversed flow, consistent with the input runner observations. The coupled simulation was shown to give good qualitative agreement with measurements, with quantitative predictions being most accurate near the catalyst centre but less accurate at locations closer to the outer wall.
Thermo-Fluid Dynamic Modelling of a Six-Cylinder Spark Ignition Engine with a Secondary Air Injection System
Authors: D'Errico G , Onorati A
Published: May 2006

This paper deals with the modelling of one-dimensional (1D) unsteady flows in the complete exhaust system of spark-ignited (SI) engines with secondary air injection, to reduce the catalyst light-off time and to speed up the after-treatment system warm-up. In particular, the numerical code GASDYN, developed by the authors, has been extended to model the injection of air in the exhaust manifold, simulating the post-oxidation of pollutant emissions in the ducts. The main chemical reactions arising in the gas phase, in the upper part of the exhaust manifold, have been included, considering the oxidation of C3H6, C3H8, and CO, and the steam reforming of C3H6 and C3H8. The heat released in the gas due to the exothermal reactions has been taken into account to evaluate the exhaust gas temperature caused by the injection of air. The gas composition in the exhaust pipe system is imposed by the cylinder discharge process after the calculation of the combustion process via a thermodynamic multi-zone combustion model, based on a ‘fractal’ approach and augmented by kinetic emission sub-models for the prediction of emissions. A sub-model for the catalytic converter has been applied to simulate the pre-catalysts and the main catalysts from a fluid dynamic, thermal, and chemical point of view, pointing out the influence of secondary air injection parameters on the conversion efficiency of pollutants during the system warm-up. A Fiat-GM Powertrain, six-cylinder 3.2 l automotive SI engine (for Alfa Romeo) complying with Euro IV regulations has been modelled, in order to predict the chemical specie concentration along the exhaust system, allowing for reactions in gas and solid phases and taking account of the consequent heat released, which notably influences the wall and gas temperatures with and without secondary air injection. A large set of experimental data concerning this engine (in-cylinder pressures, pressure pulses, chemical composition along the system) has enabled a comprehensive comparison between predictions and measurements, in order to validate the model in different operating conditions.
Alternative Fuel for a Standard Diesel Engine
Authors: Hull A , Golubkov I , Kronberg B , van Stam J
Published: May 2006

Alternative fuels have been developed for the commercial diesel products Mk1 and EN590. Appropriate additives were selected from a broad range of oxygenates including alcohols, acetals, ethers, esters, and nitrates by a process of systematic elimination. The resulting fuels called Biodiesel 15 meet all existing standards in force for diesel fuel, are stable, and have similar performance characteristics to standard diesel. Significantly Biodiesel 15 is much cleaner than standard diesel with around 30 per cent or more reductions in particulate matter in the exhaust emissions. Carbon dioxide (CO2) emissions are much lower with Biodiesel 15 than with standard diesel products. Other regulated emissions are on a par with Mk1. The fuel consumption of Biodiesel 15 is 2 per cent lower than that of conventional Mk1.
Development of a Flame Propagation Model for Dual-Fuel Partially Premixed Compression Ignition Engines
Authors: Singh S , Liang L , Kong S-C , Reitz R D
Published: May 2006

The limitations of an existing characteristic-time combustion (CTC) model are explored and a new combustion model is developed and applied to simulate combustion in dual-fuel engines in which the premixed natural gas is ignited by the combustion flame initiated by a diesel spray. The model consists of a diesel auto-ignition model and a flame propagation model. A G-equation-based model previously developed to simulate SI engine combustion was incorporated with an auto-ignition model to simulate the flame propagation process in partially premixed environments. The computer code is based on the KIVA-3V code and consists of updated sub-models to simulate more accurately the fuel spray atomization, auto-ignition, combustion, and emissions processes. Modifications were made to implement the level set G-equation approach and to track the location of the flame as a function of the turbulent flame speed, flame curvature, flow velocity, and the movement of the computational mesh in the engine environment. Good agreement with engine experiments was obtained by using the present model.
Conductometric Studies on the Triple Ion and Quadrupole Formations from Lithium and Tributylammonium Trifluoroacetates in Protophobic Aprotic Solvents
Authors: Hojo Masashi , Miyauchi Yoshihiro , Nakatani Itsuki , Mizobuchi Taiji , Imai Yoshihiko
Published: May 2006

The observed conductivity data of CF3COOLi in propylene carbonate were properly explained by the strong formation of the quadrupole (M2X2, M = Li+ and X = CF3COO−), in addition to the symmetrical formation of the triple ions (M2X+ and MX2−) and the ion pair formation.
Transient Absorptions Due to Solvated Complexes of [Bis(salicylaldehyde)-o-phenylenediiminato]cobalt(II)
Authors: Ohashi Yukako
Published: May 2006

Transient absorptions due to a photo-induced solvation at phenolic oxygen atoms were observed for [Co(saloph)], [Co(saloph)(py)] and [Co(saloph)(py)O2] in dichloromethane.
Shape Selective Catalysis by ZSM-5 in Disproportionation of 2-Methylnaphthalene
Authors: Matsuda Takeshi , Yogo Katsunori , Mogi Yashuhiro , Kikuchi Eiichi
Published: May 2006

Disproportionation of methylnaphthalene(MN) was carried out on ZSM-5 catalysts. The external acid sites were eliminated by dealumination with (NH4)2SiF6. The dealuminated ZSM-5 gave 2,6- and 2,7-dimethylnaphthalene(DMN) from disproportionation of 2-methylnaphthalene(MN), due to its shape selective property.
Gallium Chloride-Mediated Allylation of Dithioacetals with Allylstannanes
Authors: Saigo Kazuhiko , Hashimoto Yukihiko , Kihara Nobuhiro , Hara Ken-ichi , Hasegawa Masaki
Published: May 2006

In the presence of gallium chloride, dithioacetals reacted with allylstannanes to give the corresponding homoallyl sulfides in high yields. The present method could be applied to the chemoselective allylation of bis(dithioacetal) of keto aldehyde, and the dithioacetal arising from keto function reacted with allylstannane exclusively.
Highly Diastereoselective Synthesis of cis-2,3-Disubstituted γ-Lactones by the Reaction of 2,2-Dialkoxy-3-alkylcyclopropanecarboxylic Esters with Symmetric Ketones
Authors: Saigo Kazuhiko , Shimada Shigeru , Hashimoto Yukihiko , Nagashima Tadamichi , Hasegawa Masaki
Published: May 2006

In the presence of titanium(IV) chloride, 2,2-dialkoxy-3-alkylcyclopropanecarboxylic esters reacted with symmetric ketones to give cis-2,3-disubstituted γ-lactones with high diastereoselectivity. The resulting cis-lactones were easily converted into trans-isomers by treatment with a catalytic amount of sodium ethoxide.
Electrochemical Fixation of CO2 in Acetyl-coenzyme A to Yield Pyruvic Acid Using Pyruvate Dehydrogenase Complexes as an Electrocatalyst
Authors: Kuwabata Susumu , Morishita Nobuyasu , Yoneyama Hiroshi
Published: May 2006

Electrochemical fixation of CO2 in acetyl-coenzyme A has successfully been accomplished by using pyruvate dehydrogenase complex as an electrocatalyst. The production of pyruvic acid was enhanced when coenzyme A, which was a byproduct in the pyruvic acid production, was converted to the substrate in situ in the electrolytic cell with assistance of acetyl phosphate and phosphotransacetylase.
A Novel Transesterification of Thioesters with Alcohols by an Electrochemical Activation
Authors: Yamaguchi Masahiko , Tsukamoto Yukiharu , Minami Toru
Published: May 2006

Esters were synthesized from thioesters and alcohols in high yields by an electrochemical activation. Different results were obtained by the use of n-Bu4N+ I− and LiBF4 as the electrolyte.
Intracellular Voltammetry in a Single Protoplast with an Ultramicroelectrode
Authors: Uchida Isamu , Abe Takayuki , Itabashi Takeyuki , Matsue Tomokazu
Published: May 2006

Silver ring ultramicroelectrodes with tip diameter of 1 μm or less were fabricated by electroless plating in a glass capillary. The ultramicroelectrode was inserted in a living protoplast of Bryopsis plumosa and the oxygen concentration inside the cell was estimated from the steady-state current observed in a voltammogram.
ESR Spectra of Transient Radical Cations of NADH Analogues
Authors: Fukuzumi Shunichi , Kitano Toshiaki
Published: May 2006

Electron spin resonance (ESR) spectra of transient radical cations of 9,10-dihydro-10-methylacridine and derivatives, which are NADH analogues, are observed in electron transfer reactions from the NADH analogues to Fe3+ or Cu2+ in acetonitrile.
Michael Addition of 2,2-Difluoroketene Silyl Acetal. Preparation of 4,4-Difluoroglutamic Acid and 5,5-Difluorolysine
Authors: Kitagawa Osamu , Hashimoto Akihiro , Kobayashi Yoshiro , Taguchi Takeo
Published: May 2006

2,2-Difluoroketene silyl acetal, generated in situ by treating methyl difluoroiodoacetate with Zn followed by chlorosilane, readily reacted with α,β-unsaturated carbonyl compounds or acetals to give the 1,4-addition products, preferentially. The difluoro analogs of glutamic acid and lysine were prepared through the present reaction.
Asymmetric Cleavage of 9-Azabicyclo[3.3.1]nonan-3-one into cis-2,6-Disubstituted Piperidine. A Facile Approach to a Chiral Building Block for Alkaloid Synthesis
Authors: Momose Takefumi , Toyooka Naoki , Hirai Yoshiro
Published: May 2006

An asymmetric cleavage of the ‘fork head’ ketone of 9-azabicyclo[3.3.1]nonan-3-one gave a cis-2,6-disubstituted piperidine derivative in 93% ee, which was transformed to the cis-2,6-bis(hydroxymethyl)piperidine derivative, a versatile chiral building block.
Synthesis of 5-Deoxy-3-O-methyl-5-phenylphosphinyl-L-fucopyranoses. The First P-in-Ring Sugar Analogs of L-Fucose Type
Authors: Hanaya Tadashi , Ohmae Takeshi , Kawamoto Heizan , Yamamoto Hiroshi
Published: May 2006

Starting from 1,2:5,6-di-O-isopropylidene-β-D-altrofuranose, 5,6-dideoxy-1,2-O-isopropylidene-5-[(methoxy)phenylphosphiny1]-3-O-methyl-β-D-arabino-hexofuranose was prepared in a 6 step sequence (13% overall yield). It was converted into the title compounds, which were characterized as the 1,2,4-triacetates.
Atropisomerism in a Molecular Gear, 8-Bromo-1,4-dimethyl-9-(2-methylbenzyl)triptycene
Authors: Yamamoto Gaku
Published: May 2006

Two rotamers, ap and sc1, of the title compound were separately isolated as stable entities at room temperature. The rotamers gave an equilibrium mixture of the two at elevated temperatures, K([ap]/[sc1]) being 2.26 at 60 °C in toluene-d8. The kinetic parameters for the sc1 → ap conversion are as follows: ΔH‡ = 26.3 ± 0.6 kcal mol−1 (1 cal = 4.184 J), ΔS‡ = −2.7 ± 1.8 cal mol−1 K−1, ΔG‡350K = 27.2 kcal mol−1.
Selective Synthesis of (Z)-1-Ethylidene-2-silylcycloalkanes by Palladium-Catalyzed Hydrosilylation of 1-Vinylcycloalkenes
Authors: Hayashi Tamio , Hengrasmee Sunantha , Matsumoto Yonetatsu
Published: May 2006

Hydrosilylation of 1-vinylcycloalkenes with methyldichlorosilane in the presence of a palladium catalyst proceeded with high regio- and stereoselectivity to give (Z)-1-ethylidene-2-silylcycloalkanes in high yields.
Oscillation Found in Reaction between Permanganate and Oxalic Acid
Authors: Fujiwara Kitao , Kashima Toshiyuki , Tsubota Hiroyuki , Toyoshima Yoshinori , Aihara Masato , Kiboku Mitsuo
Published: May 2006

The temporal change in absorbance of the solution was observed after mixing permanganate and oxalic acid. The oscillating structure appeared continuing more than 1 h. This oscillation was not observed by mixing permanganate with the reducing agents other than oxalic acid such as Ce3+ and As3+.
Chloro Complex of Ruthenium(III) with Trioctylmethylammonium Chloride and Its Thermal Decomposition
Authors: Watanabe Hiroshi , Utsuyama Hiroaki , Sahara Shinji
Published: May 2006

The chloro complex of ruthenium(III) with TOMAC, and its thermal decomposition behavior have been investigated. The complex exists in a polymeric chloro complex bridged with hydroxyl groups. Further, the thermal decomposition process of the complex was proposed.
Electrocatalytic Synthesis of a Cobaltocenium/ferrocene Bilayer-like Film Acting as a Solid State Diode
Authors: Ando Yoshiyuki , Nishihara Hiroshi , Aramaki Kunitsugu
Published: May 2006

Two-step electropolymerization involving reduction of Fe(C5H4CH2Cl)2 catalyzed by a poly[Co(C5CH4Cl=CHCHO)2]+/0 electrode film affords a cobaltocenium/ferrocene bilayer-like film. A device fabricated by sandwiching this film between electrodes shows diode-like i-V characteristics under a dry nitrogen atmosphere.
A Novel Synthesis of Primary Selenoamides from Nitriles by the Treatment of Bis(trimethylsilyl) Selenide and BF3·OEt2
Authors: Shimada Kazuaki , Hikage Shigeki , Takeishi Yoshiyuki , Takikawa Yuji
Published: May 2006

Reaction of nitriles with (Me3Si)2 Se in the presence of BF3·OEt2 afforded the corresponding primary selenoamides in moderate yields. A selenourea and a selenothiocarbamate were also prepared in a similar manner from the corresponding cyanamide and thiocyanate.
First Total Synthesis of Symbioramide, a Novel Ca2+-ATPase Activator from Symbiodinium sp.
Authors: Nakagawa Masako , Yoshida Jun , Hino Tohru
Published: May 2006

The first total synthesis of symbioramide (1) is described and simultaneously established the complete stereostructure of 1 to be (2S,3R,2′R,3′E)-N-(2′-hydroxy-3′-octadecenoyl)-dihydrosphingosine.
Synthesis of 3″-Dehydro-4-O-methylbarminomycin II Having an Eight-membered Acetal-azomethine Ring
Authors: Ikeda Daishiro , Ajito Keiichi , Kondo Shinichi , Takeuchi Tomio
Published: May 2006

Barminomycin I and II, an extremely potent antitumor anthracyclines, have a unique eight-membered azomethine or carbinolamine structure. (1″R,5″R)-3″-Dehydro-4-O-methylbarminomycin II was first synthesized through the hypothetical biogenetic intermediate.
Enantiodifferentiating Functionalization of Prochiral Diols by Highly Stereoselective Ring-Cleavage Reaction of Spiroacetals Derived from I-Menthone with Allyltrimethylsilane-Titanium Tetrachloride
Authors: Harada Toshiro , Ikemura Yoshifumi , Nakajima Hiroyuki , Ohnishi Jakayuki , Oku Akira
Published: May 2006

Enantiodifferentiating transformation of prochiral diols possessing σ-symmetry was realized by the utilization of titanium tetrachloride-promoted selective ring-cleavage reaction of spiroacetals derived from the diols and I-menthone with allyltrimethylsilane.
Cerium(IV) Trifluoromethanesulfonate as a Strong Oxidizing Agent
Authors: Imamoto Tsuneo , Koide Yasuhiro , Hiyama Susumu
Published: May 2006

Cerium(IV) trifluoromethanesulfonate was prepared by the reaction of cerium(IV) carbonate with trifluoromethanesulfonic acid. The powerful oxidizing ability of this compound is observed in the oxidation of benzyl alcohols and alkylbenzenes.
The Efficient Catalytic Asymmetric Aldol-type Reaction
Authors: Kobayashi Shu , Fujishita Yuko , Mukaiyama Teruaki
Published: May 2006

A wide variety of aldehydes including aromatic, aliphatic and α,β-unsaturated aldehydes react with silyl enol ether of S-ethyl propanethioate in propionitrile to afford the corresponding aldol-type adducts with high relative and absolute stereochemical control by use of chiral diamine coordinated tin(II) triflate as a catalyst.
Stereoselectivity in the Coupling Reaction between 2-Phenylthio-2,3-dideoxyribose and Silylated Pyrimidine Bases
Authors: Kawakami Hiroshi , Ebata Takashi , Koseki Koshi , Matsushita Hajime , Naoi Yoshitake , Itoh Kazuo
Published: May 2006

Coupling reaction between 2-α-phenylthio-2,3-dideoxyribose and silylated pyrimidine bases in the presence of SnCl4 proceeded stereoselectively to give the β-anomers. These nucleosides were converted to 2′,3′-dideoxy-2′,3′-didehydronucleosides by oxidation followed by thermal elimination.
Synthesis of Dimeric and Trimeric Porphyrins Based on Intramolecular Macrocyclization Reactions
Authors: Osuka Atsuhiro , Kobayashi Fumikazu , Maruyama Kazuhiro
Published: May 2006

An useful method based on acid-catalyzed intramolecular macrocyclization was developed for the synthesis of dimeric and trimeric porphyrins with constrained geometries.
Pyrolysis of Methane into Higher Hydrocarbons on Carbon Fibers
Authors: Mochida Isao , Aoyagi Yusuke , Fujitsu Hiroshi
Published: May 2006

Pyrolysis of methane over pitch based carbon fibers at 1173–1273 K produced rather selectively C2 hydrocarbons (selectivity up to 67%) at a stational conversion of 20% with limited deposition of carbon (18%).
An Application of Polypyrrole Films Electropolymerized in NaOH Aqueous Solution to Non-linear MIM Devices
Authors: Osaka Tetsuya , Ouchi Kiyoshi , Fukuda Toshihiro
Published: May 2006

Thin films of electroinactive polypyrrole(PPy) were electropolymerized in NaOH aqueous solutions on ITO(indium tin oxide) electrode. The PPy films were used at as-prepared condition without undoping process. The metal-insulator-metal(MIM) structure was fabricated by sputtering ITO on the PPy films to give ITO/PPy/ITO devices. The devices showed non-linear and symmetric I–V characteristics, where the currents sharply increased at ca. ±5 V.
Selective Mono- and Dicarbonylation of Terminal Olefins Catalyzed by Pd–C in the Presence of Cu(II) or Cu(I) Chloride under Mild Conditions
Authors: Inomata Katsuhiko , Toda Shiho , Kinoshita Hideki
Published: May 2006

Pd–C can catalyze the carbonylation of terminal olefins with normal pressure of carbon monoxide at room temperature. The corresponding mono- and diesters (succinates) were selectively formed in excellent yields using Cu(II) and Cu(I) chloride, respectively, in alcohol.
Discrimination of Drinks with a Novel Sensing System Detecting Electrochemical Nonlinearity
Authors: Nakata Satoshi , Yoshikawa Kenichi
Published: May 2006

We propose a novel strategy for the development of a chemical sensor based on the information of electrochemical nonlinearity. A sinusoidal voltage is applied to a test solution and the resulting output current is analyzed by the Fast Fourier transformation (FFT). From the higher harmonic components in the FFT, voltage dependences of both capacitance and conductance are evaluated. This method may become a powerful analytical tool with the selection of suitable metal electrodes.
Optically Active Organometallic Complexes of Heptafulvalene and 1,2-Homoheptafulvalene
Authors: Morita Noboru , Ito Shunji , Asao Toyonobu , Sotokawa Hideo , Hatano Masahiro , Tajiri Akio
Published: May 2006

Racemic and/or optically active 7-methyltropone-Fe(CO)3, tropone-Cr(CO)3, and endo- and exo-homotropone-Fe(CO)3 reacted with 8-oxoheptafulvene to afford the corresponding racemic and/or optically active heptafulvalene metal complexes, respectively. Endo- and exo-homoheptafulvalene-Fe(CO)3 reacted with TCNE to give [2+4]π and [2+8]π cycloadducts, respectively.
Fatigue-resistant Photochromic Hemithioindigoes
Authors: Ichimura Kunihiro , Seki Takahiro , Tamaki Takashi , Yamaguchi Takeo
Published: May 2006

The hemithioindigo derivatives have been found to show satisfactory photoresponses even after more than 104 cycles of alternate irradiation with the lights which can induce a Z–E isomerization.
Ene Reaction of Allenyl Sulfides with Aldehydes and Schiffs Bases Catalyzed by Lewis Acids
Authors: Hayashi Yujiro , Shibata Takanori , Narasaka Koichi
Published: May 2006

Ene reaction proceeds between α-alkylallenyl sulfides and enophiles such as aldehydes and Schiffs bases in the presence of Lewis acid to afford various 1,3-dienes.
Novel Synthesis of (2S, 3R, 4S)-4-Amino-5-cyclohexyl-1-morpholino-2,3-pentanediol and (2S, 3R, 4S)-2-Amino-1-cyclohexyl-6-methyl-3,4-heptanediol, the C-Terminal Components of Renin Inhibitors
Authors: Kobayashi Yuko , Nakatani Kazuhiko , Ito Yoshio , Terashima Shiro
Published: May 2006

The title synthesis could be accomplished in a highly stereo- and regioselective manner by employing epoxide formation with inversion of configuration followed by epoxide opening with a nucleophile.
On the Reaction Pathway and Stereochemistry of Allylic Tin Reagents-Benzaldehyde Condensation. A Substituent Effect Study
Authors: Yamataka Hiroshi , Nishikawa Kazuyoshi , Hanafusa Terukiyo
Published: May 2006

A substituent effect study on the reactivity and steneoselectivity of the Lewis acid mediated addition of allyl- and crotylstannanes to arylaldehydes indicates that the reaction proceeds via a polar antiperiplanar transition state with the exception of 2,4,6-trimethylbenzaldehyde, for which a cyclic pathway competes with the open pathway.
Practical Chemical Synthesis of RNA Fragments. Improvement in the Preparation of Ribonucleosidephosphoramidite Units
Authors: Tanimura Hiroshi , Imada Takashi
Published: May 2006

Highly pure ribonucleoside phosphoramidite units were prepared and three 20 long RNA fragments were synthesized on the solid phase by use of these starting compounds.
A Convenient Electrochemical Method for Conversion of 4-Haloacetophenone to 1-(4-Halophenyl)ethanol
Authors: Ikeda Yoshikazu
Published: May 2006

In the presence of a catalytic amount of Sb(III), 4-fluoro-, 4-chloro-, 4-bromo-, and 4-iodoacetophenone were converted into the corresponding 1-(4-halophenyl)ethanols by an electrochemical method (−3.7 mA/cm2, 6F/mol, Pb cathode). Each alcohol yielded 91, 94, 98, and 94%, respectively.
Reactions of 4-Siloxy-1-benzopyrylium Salts with Allylsilane and Allylstannane Reagents
Authors: Ohkata Katsuo , Ishimaru Kenji , Lee Yong-gyun , Akiba Kin-ya
Published: May 2006

The reactions of allylstannanes with 4-siloxy-1-benzopyrylium salts gave the corresponding allylated derivatives more smoothly than allylsilanes. Similar reactions with 3-trimethylsilyl-1-butene afforded unexpected five-membered ring adducts in 87% and 37% yields, respectively.
Linear Chain Compounds of Molybdenum(II) Acetate Dimer Linked by Linear-bidentate Ligands, Pyrazine, 4,4′-Bipyridine, and 1,4-Diazabicyclo[2.2.2]octane
Authors: Handa Makoto , Kasamatsu Kenichi , Kasuga Kuninobu , Mikuriya Masahiro , Fujii Toshinori
Published: May 2006

Linear chain compounds, [Mo2(O2CCH3)4·L]n (L = pyrazine, 4,4′-bipyridine, 1,4-diazabicyclo[2.2.2]octane) have been prepared and characterized. The linear chain structure of alternating MO2(O2CCH3)4 units and bridging ligands L was confirmed by an X-ray structural analysis of the bpy complex.
Influence of Light Intensity on Photoe1ectroreduction of CO2 at a p-GaP Photocathode
Authors: Noda Hidetomo , Yamamoto Akio , Ikeda Shoichiro , Maeda Masunobu , Ito Kaname
Published: May 2006

The influence of the light intensity on the photoelectroreduction of CO2 was investigated at a p-GaP photocathode in 0.1 mol dm−3 KHCO3 aqueous solution. The faradaic efficiencies for the formation of HCOO− and H2 were strongly affected by the light intensity. The maximum faradaic efficiency for HCOO− production was close on 70%. A mechanism of variation of the efficiencies with light intensity was discussed.
Regioreversed Allylation in Lewis Acid-mediated and Photochemical Addition Reactions of Unsymmetric α-Diketones with Allylic Stannanes
Authors: Takuwa Akio , Nishigaichi Yutaka , Yamashita Koichi , Iwamoto Hidetoshi
Published: May 2006

In the photochemical reaction of allyl- and benzyltrimethylstannanes with unsymmetric α-diketones (PhCOCOR), the allylic group was introduced to the benzoyl carbon in high or excellent selectivity, whereas the acyl carbon was allylated either exclusively or predominantly under BF3-mediated reaction.
Enantioselective Catalysis by Artificial Tryptophan Synthase Formed with Functionalized Bilayer Membrane
Authors: Murakami Yukito , Hisaeda Yoshio , Nakamura Koichiro , Kikuchi Jun-ichi
Published: May 2006

A functionalized bilayer membrane, composed of a cationic peptide lipid having a L-histidyl residue, a hydrophobia pyridoxal derivative, and copper(II) ions, catalyzed the β-replacement reaction of serine with indole to afford tryptophan in a significant enantiomeric excess of the D-isomer.
Separation of Some Metal Thiothenoyltrifluoroacetonates and Their Pyridine Base Adducts by Reversed Phase HPLC
Authors: Tsunoda Kin-ichi , Sekiguchi Ryu-ichi , Akaiwa Hideo
Published: May 2006

Separated were 1,1,1-trifluoro-4-mercapto-4-(2-thienyl)-3-butene-2-one (thiothenoyltrifluoroacetone, STTA) chelates of Zn2+, Cu2+, Cd2+, Ni2+, Co3+ by reversed phase high performance liquid chromatography (RP-HPLC). The elution of the STTA chelates of Cd2+, Zn2+, and Ni2+ was delayed by the addition of pyridine, α-picoline, or γ-picoline, indicating the formation of the adducts.
CP/MAS 13C-NMR Studies on the Structure of Bacteriochlorophyll c in Chlorosomes from Chloroflexus aurantiacus
Authors: Nozawa Tsunenori , Suzuki Manabu , Kanno Syuichi , Shirai Syu
Published: May 2006

High resolution solid state NMR spectra have been obtained for chlorosomes by suitable choice of observation conditions, and their comparison with those of monomeric and oligomeric solid BChl c showed the presence of a hydrogen bond between the 9-carbonyl group, and the 2a-hydroxyl group.
A Stereoselective Synthesis of a Basic Skeleton of Amaryllidaceae Montanine-type Alkaloids, (±)-4a,11a-cis-11,11a-syn-5,11-Methanomorphanthridine Ring System
Authors: Hoshino Osamu , Ishizaki Miyuki
Published: May 2006

A title compound was synthesized by reductive cyclization of 4a,11a-cis-11,11a-syn-11-acetoxymethyl-N-p-tosylmorphanthridine or N-detosylated alcohol derived from a hydroxymethyl-p-tosylamide prepared by hydroboration-oxidation of cis-1-(p-to-sylamido)-2-vinylcyclohexane derivative.
Cryptoacetalide and Epicryptoacetalide, Novel Spirolactone Diterpenoids from Salvia miltiorrhiza
Authors: Asari Fumika , Kusumi Takenori , Zheng Guo-Zhi , Cen Ying-Zhou , Kakisawa Hiroshi
Published: May 2006

Two novel spirolactone diterpenoids have been isolated from the roots of Chinese medicinal plant, Salvia miltiorrhiza. Their structures were established by spectroscopic means including 2D-NMR methods.
Reactions of Dimethylsilyl Ferrocenes with Some Transition Metal Carbonyl Complexes
Authors: Kotani Sonae , Tanizawa Tsuneyoshi , Shiina Kyo , Sonogashira Kenkichi
Published: May 2006

Treatment of dimethylsilylferrocene (1) and 1,1′-bis(dimethylsilyl)ferrocene (2) with dicobaltoctacarbonyl affords the complexes containing the Si–Co σ-bond stabilized with a ferrocenyl group. The reactions of 1 or 2 with ironpentacarbonyl and trirutheniumdodecacarbonyl give the ferrocenyl derivatives bridged with Si–M–Si (M = Fe or Ru) sequences inter- or intramolecularly.
Synthesis of Conformationally Restricted Carotenoid-linked Porphyrins
Authors: Osuka Atsuhiro , Yamada Hiroko , Maruyama Kazuhiro
Published: May 2006

Carotenoid-linked porphyrin compounds were synthesized in acceptable to good yields (15–94%) by the acid-catalyzed condensation of dipyrrylmethane and carotenoid-linked aryl aldehyde. Comparison of the absorption spectra with fluorescence excitation spectra indicated the efficient intramolecular singlet energy transfer from the carotenoid to the porphyrin.
Effects of Si–Si σ-Bonds on Stability of Adjacent Benzylic Cations
Authors: Shimizu Nobujiro , Kinoshita Chieko , Osajima Erika , Tsuno Yuho
Published: May 2006

Solvolytic formation of α-pentamethyldisilanylbenzyl cation is about 7 kcal/mol energetically more favorable than that of α-trimethylsilylbenzyl cation from the corresponding bromides in 97% TFE.
XPS Determination of the Surface Composition of Vanadyl Pyrophosphate Catalysts
Authors: Okuhara Toshio , Nakama Tetsuya , Misono Makoto
Published: May 2006

The surface P/V ratios of vanadyl pyrophosphates ((VO)2P2O7), which were selective catalysts for the oxidation of butane to maleic anhydride, were determined to be close to that of the bulk (P/V = 1) by XPS using V–P–O glasses as standard materials.
Syntheses and Spectroelectrochemistry of 2-Cyanobipyridinium Derivatives
Authors: Saika Tetsuyuki , Iyoda Tomokazu , Shimidzu Takeo
Published: May 2006

Novel 2-cyanoviologen derivatives having highly anodically shifted reduction potentials were synthesized. The colors of their cation radicals showed a variety of colors as same as those of corresponding viologen derivatives.
Amphiphilic Tailor-made Proteins as Novel Chiral Hosts
Authors: Morii Hisayuki , Ichimura Kunihiro , Uedaira Hatsuho
Published: May 2006

We have designed and synthesized the proteins made up of several amphiphilic helices and the mobile linkage parts. They were proved to serve as host molecules providing hydrophobic inclusion sites. Induced circular dichroism spectra of the protein–acridine orange derivative systems were observed, which suggests the induction of asymmetric structure of the dye.
Hydrogen-Bonded Liquid Crystals. A Novel Mesogen Incorporating Nonmesogenic 4,4′-Bipyridine through Selective Recognition between Hydrogen Bonding Donor and Acceptor
Authors: Kato Takashi , Wilson Paul G , Fujishima Akira , Fréchet Jean M J
Published: May 2006

Selective recognition between a benzoic acid derivative and nonmesogenic 4,4′-bibyridine through intermolecular hydrogen bonds results in a novel molecular structure with liquid crystalline properties, in which 4,4′-bipyridine functions as a core unit.
Proton-Pumping by Purple Membrane in Combined Multilayers with a Phthalocyanine Derivative
Authors: Ogawa Kimiya , Kinoshita Sho-ichi , Nakahara Hiroo , Fukuda Kiyoshige
Published: May 2006

Combined multilayers of purple membrane and octa-n-butoxyphthalocyanine as a pH sensitive dye were prepared by horizontal lifting method. The photo-induced proton-pumping activity of bacteriorhodopsin was observed by change of absorption spectra of the multilayers in water, and the one-way transport of proton was confirmed.
Photochemical Reduction of Carbon Dioxide to Formate Catalyzed by p-Terphenyl in Aprotic Polar Solvent
Authors: Matsuoka Shinjiro , Kohzuki Takao , Pac Chyongjin , Yanagida Shozo
Published: May 2006

Photoreduction of CO2 to formic acid and a small quantity of CO can be achieved in aprotic polar solvent by using p-terphenyl as catalyst and triethylamine as a sacrificial electron donor under >290-nm irradiation.
A Novel Deselenation in the Reaction of Selenoamides with Organolithium Reagents
Authors: Sekiguchi Masahito , Ogawa Akiya , Fujiwara Shin-Ichi , Ryu Ilhyong , Kambe Nobuaki , Sonoda Noboru
Published: May 2006

The reaction of selenoamides with organolithium reagents proceeds in a carbophilic manner, and more interestingly, the presence of excess lithium reagents causes a novel deselenation reaction from the carbophilic adducts.
A Highly Efficient Synthesis of Tri-O-Acyl-α-D-Glucopyranose 1,2-(Orthoesters) under High Pressure
Authors: Gama Yasuo , Sasaki Makoto , Yasumoto Masahiko , Ishigami Yutaka
Published: May 2006

High pressure-assisted condensation reaction of acylated glucosyl bromides with complex alcohols in the presence of diisopropylethylamine and tetrabutylammonium bromide gave the corresponding 1,2-orthoesters in good to excellent yields without using heavy metal salts.