bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Electrolytes on the Redox Potential and the Rate of the CO Dissociation Reaction of Trinuclear Ruthenium Monocarbonyl Complexes Self-Assembled on an Au(111) Electrode Surface
Authors: Michi Takayuki , Abe Masaaki , Matsuno Junzo , Uosaki Kohei , Sasaki Yoichi 
Published: July 2007

Abstract
Densely packed redox-active self-assembled monolayers (SAMs) of monocarbonyl triruthenium complexes [Ru3(μ3-O)(μ-CH3COO)6(CO)(mpy)(C10PY)] (1) (mpy, 4-methylpyridine; C10PY, {(NC5H4)CH2NHC(O)(CH2)10S–}2), [Ru3(μ3-O)(μ-CH3COO)6(CO)(μ-C10PY)] (2), and [{Ru3(μ3-O)(μ-CH3COO)6(CO)(mpy)}2(μ-C10PY)] (3) have been constructed on an Au(111) electrode surface. They were characterized by infrared reflection absorption spectroscopy (IRRAS), spectroscopic ellipsometry, and contact angle measurement as well as cyclic voltammetry. Redox potential of the SAMs of 1 at the interface of aqueous electrolyte solutions shifted negatively as the concentration of HClO4 increased from 0.01 to 1.0 mol dm−3 with the slope of 0.059 V/decade and as the electrolyte was changed from H2SO4 (0.79 V vs. Ag|AgCl) to HNO3 (0.69 V) and HClO4 (0.59 V) at a fixed concentration of 0.1 mol dm−3. No significant difference in the redox potential was observed between the acid and its sodium salt. The effect is explained, as previously reported for the ferrocenylalkanethiol and non-carbonyl triruthenium SAMs, in terms of the effective ion pair formation in the order ClO4− &gt; NO3− &gt; SO42−. The rate of the CO dissociation reaction of the complex in the SAMs (complete within a few minutes at room temperature) that occurs in the oxidation state of Ru3III,III,III was not very sensitive to the applied electrode potential (0.6–0.8 V), but increased by ca. 2.5 times as the concentration of HClO4 (0.01–1.0 mol dm−3) was lowered, and by ca. one-order of magnitude as the electrolyte anions was changed from ClO4− to SO42− and NO3−.
Co3O4 Nanostructures with Different Morphologies and their Field‐Emission Properties
Authors: Varghese B. , Teo C. H. , Zhu Y. , Reddy M. V. , Chowdari B. V. R. , Wee A. T. S. , Tan V. B. C. , Lim C. T. , Sow C.‐H. 
Published: July 2007

AbstractWe report an efficient method to synthesize vertically aligned Co3O4 nanostructures on the surface of cobalt foils. This synthesis is accomplished by simply heating the cobalt foils in the presence of oxygen gas. The resultant morphologies of the nanostructures can be tailored to be either one‐dimensional nanowires or two‐dimensional nanowalls by controlling the reactivity and the diffusion rate of the oxygen species during the growth process. A possible growth mechanism governing the formation of such nanostructures is discussed. The field‐emission properties of the as‐synthesized nanostructures are investigated in detail. The turn‐on field was determined to be 6.4 and 7.7 V μm–1 for nanowires and nanowalls, respectively. The nanowire samples show superior field‐emission characteristics with a lower turn‐on field and higher current density because of their sharp tip geometry and high aspect ratio.
Lanthanide Class of a Trinuclear Enantiopure Helical Architecture Containing Chiral Ligands: Synthesis, Structure, and Properties
Authors: Lama Marco , Mamula Olimpia , Kottas Gregg S. , Rizzo Fabio , De Cola Luisa , Nakamura Asao , Kuroda Reiko , Stoeckli‐Evans Helen 
Published: July 2007

AbstractThe pinene‐bipyridine carboxylic derivatives (+)‐ and (−)‐HL, designed to form configurationally stable lanthanide complexes, proved their effectiveness as chiral building blocks for the synthesis of lanthanide‐containing superstructures. Indeed a self‐assembly process takes place with complete diastereoselectivity between the enantiomerically pure ligand L−and LnIIIions (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er), thus leading to the quantitative formation of a trinuclear supramolecular architecture with the general formula [Ln3(L)6(μ3‐OH)(H2O)3](ClO4)2(abbreviated as tris(Ln[L]2)). This class ofC3‐symmetrical compounds was structurally characterized in the solid state and solution. Electrospray (ES) mass spectrometric and1H NMR spectroscopic analyses indicated that the trinuclear species are maintained in solution (CH2Cl2) and are stable in the investigated concentration range (10−2–10−6 m). The photophysical properties of the ligand HL and its tris(Ln[L]2) complexes were studied at room temperature and 77 K, thus demonstrating that the metal‐centered luminescence is well sensitized both for the visible and near‐IR emitters. The chiroptical properties of tris(Ln[L]2) complexes were investigated by means of circular dichroism (CD) and circularly polarized luminescence (CPL). A high CD activity is displayed in the region of π–π* transitions of bipyridine. CPL spectra of tris(Eu[(+)‐L]2) and tris(Tb[(+)‐L]2) present large dissymmetry factorsgemfor the sensitive transitions of EuIII(5D0→7F1,gem=−0.088) and TbIII(5D4→7F5,gem=−0.0806). The self‐recognition capabilities of the system were tested in the presence of artificial enantiomeric mixtures of the ligand.1H NMR spectra identical to those of the enantiomerically pure complexes and investigations by CD spectroscopic analysis reveal an almost complete chiral self‐recognition in the self‐assembly process, thus leading to mixtures of homochiral trinuclear structures.
Phase 2 study of erlotinib in patients with unresectable hepatocellular carcinoma
Authors: Thomas Melanie B. , Chadha Romil , Glover Katrina , Wang Xuemei , Morris Jeffrey , Brown Thomas , Rashid Asif , Dancey Janet , Abbruzzese James L. 
Published: July 2007

AbstractBACKGROUND.Growth factor overexpression, including epidermal growth factor receptor (EGFR) expression, is common in hepatocellular cancers. Erlotinib is a receptor tyrosine kinase inhibitor with specificity for EGFR. The primary objective of this study was to determine the proportion of hepatocellular carcinoma (HCC) patients treated with erlotinib who were alive and progression‐free (PFS) at 16 weeks of continuous treatment.METHODS.Patients with unresectable HCC, no prior systemic therapy, performance status (PS) of 0, 1, or 2, and Childs‐Pugh (CP) cirrhosis A or B received oral erlotinib 150 mg daily for 28‐day cycles. Tumor response was assessed every 2 cycles by using Response Evaluation Criteria in Solid Tumors (RECIST; National Cancer Institute Cancer Therapy Evaluation Program, Bethesda, Md) criteria. Patients accrued to either “low” or “high” EGFR expression cohorts; each cohort had stopping rules applied when there was a lack of efficacy.RESULTS.Forty HCC patients were enrolled. Median age was 64 years (range, 33–83 years), sex distribution was 32 males and 8 females, performance scores were 40% PS 0, 55% PS 1, Childs‐Pugh distribution was 75% A and 20% B. There were no complete or partial responses; however, 17 of 40 patients achieved stable disease at 16 weeks of continuous therapy. The PFS at 16 weeks was 43%, and the median overall survival (OS) was 43 weeks (10.75 months). No patients required dose reductions of erlotinib. No correlation between EGFR expression and outcome was found.CONCLUSIONS.Results of this study indicated that single‐agent erlotinib is well tolerated and has modest disease‐control benefit in HCC, manifested as modestly prolonged PFS and OS when compared with historical controls. Cancer 2007. Published 2007 by the American Cancer Society.
Reactive Plasma‐Aided RF Sputtering Deposition of Hydroxyapatite Bio‐implant Coatings
Authors: Long J. , Sim L. , Xu S. , Ostrikov K. 
Published: July 2007

AbstractThe plasma‐assisted RF sputtering deposition of a biocompatible, functionally graded calcium phosphate bioceramic on a Ti6Al4 V orthopedic alloy is reported. The chemical composition and presence of hydroxyapatite (HA), CaTiO3, and CaO mineral phases can be effectively controlled by the process parameters. At higher DC biases, the ratio [Ca]/[P] and the amount of CaO increase, whereas the HA content decreases. Optical emission spectroscopy suggests that CaO+ is the dominant species that responds to negative DC bias and controls calcium content. Biocompatibility tests in simulated body fluid confirm a positive biomimetic response evidenced by in‐growth of an apatite layer after 24 h of immersion.
Molecular Dynamics Simulations of the Growth of Thin A‐C:H Films Under Additional Ion Bombardment: Influence of the Growth Species and the Ar+ Ion Kinetic Energy
Authors: Neyts E. , Eckert M. , Bogaerts A. 
Published: July 2007

AbstractMolecular dynamics (MD) simulations are used to investigate the growth of thin, amorphous, hydrogenated carbon films for conditions corresponding to an argon/acetylene expanding thermal plasma with additional ion bombardment. It is shown that the hydrocarbon growth species determines the final structure of the film, in particular how the Ar+ ions contribute to the growth process. Attention is focused on how the Ar+ ion energy and flux influence the morphology of the films, the hydrogen content, the density, and the carbon coordination in the films due to a knock‐on penetration mechanism.
Two optimized combination assays to examine apoptosis pathways in clinical samples
Authors: Hollier Mark , Whistler Toni , Dawson Carolyn , Vernon Suzanne D. 
Published: July 2007

AbstractBackground:A consequence of a number of diseases is an alteration in apoptosis. Currently, there is no single assay that measures the main stages of apoptosis, requiring that multiple assays be performed. This hinders studies on clinical samples that have limited cell numbers. Our objective was to combine and optimize assays that target specific stages of apoptosis for use in a typical clinical blood sample.Methods:Two flow cytometric assays were developed for use on peripheral blood mononuclear cells (PBMC) collected in two 8‐ml tubes from a single draw. One measures caspase‐12 activity, the level of active caspase‐3 and DNA fragmentation. The second assesses depolarization of the mitochondria and phosphatidylserine externalization. Cell populations present within the samples were determined by flow cytometry. Apoptosis was validated by ELISA.Results:Each assay was optimized for use with cell numbers and sample volumes typical of clinical blood samples. Each combination assay effectively distinguished apoptotic from nonapoptotic blood cells.Conclusions:This combined optimized method comprised of two independent assays makes it possible to assay the major pathways of apoptosis in addition to determining the blood cell subsets that are affected. Published 2007 Wiley‐Liss, Inc.
Over expression of glutamate cysteine ligase increases cellular resistance to H2O2‐induced DNA single‐strand breaks
Authors: Shi Shengli , Hudson Francesca N. , Botta Dianne , McGrath Monica B. , White Collin C. , Neff‐LaFord Haley D. , Dabrowski Michael J. , Singh Narendra P. , Kavanagh Terrance J. 
Published: July 2007

AbstractHydrogen peroxide (H2O2) can cause single strand DNA breaks (ssDNA) in cells when the mechanisms normally in place to reduce it are overwhelmed. Such mechanisms include catalase, glutathione peroxidases (GPx), and peroxiredoxins. The relative importance of these enzymes in H2O2 reduction varies with cell and tissue type. The role of the GPx cofactor glutathione (GSH) in oxidative defense can be further understood by modulating its synthesis. The first and rate‐limiting enzyme in GSH synthesis is glutamate‐cysteine ligase (GCL), which has a catalytic subunit (Gclc) and a modifier subunit (Gclm). Using mouse hepatoma cells we evaluated the effects of GCL over expression on H2O2‐induced changes in GSH and ssDNA break formation with the single cell gel electrophoresis assay (SCG or comet assay), and the acridine orange DNA unwinding flow cytometry assay (AO unwinding assay). Cells over expressing GCL had higher GSH content than control cells, and both SCG and AO unwinding assays revealed that cells over expressing GCL were significantly more resistant to H2O2‐induced ssDNA break formation. Furthermore, using the AO unwinding assay, the prevalence of H2O2‐induced breaks in different phases of the cell cycle was not different, and the degree of protection afforded by GCL over expression was also not cell cycle phase dependant. Our results support the hypothesis that GCL over expression enhanced GSH biosynthesis and protected cells from H2O2‐induced DNA breaks. These results also suggest that genetic polymorphisms that affect GCL expression may be important determinants of oxidative DNA damage and cancer. © 2007 International Society for Analytical Cytology
Application of complex kalman filter to NMR spectroscopy
Authors: Nishiyama Kiyoshi , Mita Tutomu 
Published: July 2007

AbstractThe Fourier transform NMR (nuclear magnetic resonance) spectroscopy is used widely at present as a noninvasive method in the structural analysis of macromolecules in organic chemistry and in the metabolic study of tissue and cells in biochemistry. We believe, however, that the Fourier transform is not adequate in the determination of the density distribution of the nucleus. the NMR signal contains essentially the relaxation (a kind of damping) phenomena, but the Fourier transform does not take this fact into consideration. Consequently, the obtained NMR spectrum is degraded both in intensity and resolution, providing apparent nucleus density distribution which is different from the true value. This paper proposes an estimation of the NMR spectrum, which positively takes the relaxation phenomenon into consideration. the method is derived by extending the Kalman filter to the complex stochastic system and applying the result to the NMR signal represented by the complex stochastic system. the proposed method is applied to the NMR signal of proton (1H) obtained from mayonnaise in 2[T] static magnetic field. the result is compared with the NMR spectrum obtained by the Fourier transform, and it is shown that the resolution and the intensity are improved drastically.
Analysis and minimization of roundoff noise in separable denominator multidimensional digital filters
Authors: Zhao Qiangfu , Kawamata Masayuki , Higuchi Tatsuo 
Published: July 2007

AbstractThis paper studies the analysis and minimization of roundoff noise in separable denominator multidimensional (SD M‐D) digital filters on the basis of state‐space representations. First, the roundoff noise in SD M‐D digital filters is analyzed and the l2‐norm dynamic range constraint is discussed. Using the results, a synthesis method of optimal realizations (with respect to roundoff noise) is proposed. Further, the simple relation between balanced realizations and optimal realizations of SD M‐D digital filters is obtained and an efficient method for synthesizing optimal realizations from balanced realizations is proposed. In addition, this paper also proves that optimal realizations are free of overflow oscillations under zero input conditions. Finally, the synthesis procedure is illustrated by a numerical example.
Design and analysis of low‐sensitivity all‐pole low‐pass switched capacitor filters
Authors: Inoue Takahiro , Ueno Fumio 
Published: July 2007

AbstractAll‐pole switched capacitor filters (SCFs) having a zero worst‐case sensitivity of amplitude response in their passband are proposed, together with their approximate and exact design methods. In the approximate design method, a normalized doubly terminated LC ladder filter which satisfies given specification is used for an analog reference filter. the LDI s‐a transformation is applied to the equations representing this circuit. Stable equations representing the approximated circuit are obtained by replacing the terminal resistances with frequency‐ dependent cosine‐function resistances. the design is carried out based on these equations. In the exact design method, a doubly terminated unit‐element filter which satisfies specifications is used as a reference filter. From its lumped‐element equivalent circuit using two kinds of complex‐frequency variables, equations in the same form as those of the foredescribed approximated circuit are obtained. the SCFs are designed based on these equations.In this paper, first, a general Circuitstructure in which the minimum worst‐case sensitivity of amplitude response in the passband can be zero is shown. Based on this, formulas of the approximate and exact designs of an all‐pole low‐pass SCF circuit are given. As an example, the design of a third‐order all‐pole low‐pass SCF is shown. the proposed SCF is compared with a typical conventional SCF, and excellence of the former, such as a low element sensitivity, is demonstrated.
Stopping rules based on a posteriori probability for every pattern and every stage
Authors: Suzuki Joe , Matsushima Toshiyasu , Hirasawa Shigeichi , Inazumi Hiroshige 
Published: July 2007

AbstractThe algorithms for pattern recognition systems considering the observation cost from the viewpoint of the system, can be re duced to the problems of stopping rule in which we must determine when the observation should be stopped. As the stopping rule in the Bayesian pattern recognition, methods based on DP search first given by K. S. Fu et al. is known to be the optimum in the sense of the minimum risk. A problem in those methods is that an exponential amount of data must be stored in memory for each observation stage, which is hard to realize. This paper discusses the new class of stopping rules, where the optimum thresholds based on a posteriori probability are chosen for each pattern and for each stage. the proposed method is not applicable to the problem where the patterns have strong correlations in the observed values along each dimension, but it can realize almost the same performance from the viewpoint of the minimum risk, while eliminating the number of parameters to be stored. the method also provides a model for the conventional method to set the border for the likelihood ratio when the a priori probabilities of the patterns are distributed uniformly.
A simplification of computation for optimal control problems using fixed‐point theorem
Authors: Shidama Yasunari , Ohta Toyomi , Yamaura Hiroo 
Published: July 2007

AbstractThis paper proposes a first‐order algorithm for unconstrained nonlinear optimal control problems based on the fixed point theorem. the method has the following features: (a) the algorithm is simple; (b) unlike second‐order algorithms, the choice of the first approximation is less critical; and (c) unlike gradient methods, experimental selections of parameters during iterative calculations are not required. This paper also describes the conditions of convergence of the algorithm in the space of continuous functions, and the optimality of a solution derived.
An error analysis of an approximation method for band‐limited signals using minimum energy signal‐existence of the optimum number of sampling points and its estimation
Authors: Uyematsu Tomohiko , Sakaniwa Kohichi , Kishi Genya 
Published: July 2007

AbstractFor an approximation problem of band‐limited signals, “minimum energy signal” is defined as a band‐limited waveform with minimum energy that takes the specified sample valueas at the given sampling points.By using minimum energy signals, we have already reported a new approximation method for band‐limited signals. In the proposed method, sampling points are selected from a given time interval so as to minimize the square error between the original and the approximation signals. However, when this approximation method is realized with a digital hardware or a digital computer, there are round‐off noises in sample values due to the finite word length of the hardware system. Thus, to employ our proposed approximation method in practice, it is essentially important to analyze the effect of this round‐off noise.In this paper, some properties of minimum energy signals are investigated when the sample values of the signal are quantized to fit a finite word length of the hardware, i.e., a fixed‐point of floating point format. Also, it is shown that an optimum number of sampling points may exist when the proposed approximation method is applied to signals with noise. Moreover, by considering the effect of noise in advance, we propose a method to estimate the optimum number of sampling point as well as to determine the statistically optimum sampling points.
An optimal symbolic reliability expression using spanning trees for source‐to‐all‐terminal systems
Authors: Noda Takashi , Higashiyama Youichi , Ariyoshi Hiromu , Shirakawa Isao 
Published: July 2007

AbstractIn the probabilistic graph, SAT reliability may be defined as the probability that there exists at least one path consisting only of successful edges from s (source vertex) to every other vertex. The SDP method enumerates Boolean product terms corresponding to each of the minimal sets of edges (tree or cutset) whose success or failure results in successful or failed graph operation. The method then generates the reliability formula by transforming a Boolean sum of products into an equivalent form in which all terms are disjoint. However, this method has disadvantages in that in the process of transformation an intermediate product term should be compared with partially formed disjoint terms to determine the term to be retained or dropped, and the amount of computation time is dominated by the number of comparisons.This paper defines an optimal SAT reliability formula which is the one with a minimal number of product terms. Next, the expected property and ordering of the minimal sets for generating the optimal formula are discussed and some conditions are presented to obtain an optimal one whose number of terms is equal to the number of minimal sets. Furthermore, this paper proposes an optimal method which has a fundamental operation to enumerate spanning trees by edge reductions (open‐ or short‐circuiting) and derives an optimal formula such that the number of terms in the SAT reliability formula is equal to the number of spanning trees and each term of the formula can be determined from a spanning tree and its particular chords without use of Boolean algebra. Since every term is determined directly without comparisons at a time when a tree is generated, it seems to result in less computation time and remarkable saving of the memory space compared with the SDP method using a set of minimal cutsets.
Bandpass magnitude and delay approximations using digital transfer functions
Authors: Yamaguchi Yasuhiro , Tomiyama Shigenori , Takebe Tsuyoshi 
Published: July 2007

AbstractThis paper proposes a method to approximate transfer functions of magnitude and delay digital equalizers for transmission channels with bandpass characteristics. In this method, an extrapolation band is added to the equalization band on the unit circle on the z‐plane, and the resulting extended approximation band is mapped on the overall unit circle on the auxiliary complex plane.In the magnitude equalization, the all‐pole type transfer function is used for the approximation to have a loss from the extended approximated band. On the auxiliary complex plane, the desired characteristics are squared and inverted. Then the extrapolation characteristics are determined, and the inverted desired characteristics are expanded into Fourier cosine series. This series is transformed inversely into the z‐plane to determine the denominator of the transfer function. If the extrapolation characteristics are determined improperly, the resulting transfer functions may become unrealizable.This paper proposes a method of determining the extrapolation characteristics so that it always gives realizable transfer functions. In the delay equalization using the auxiliary complex plane, the approximation cannot be performed in a straightforward manner. In the proposed method, the delay characteristics are treated graphically and the inverted characteristics are expanded into Fourier cosine series. After inverse transformation into the z‐plane, the inverse of the series is expanded into the Fourier series and truncated in some length to give the transfer function.