bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploration of the Ca2+ Interaction Modes of the Nifedipine Calcium Channel Antagonist
Authors: Liu Huichun , Zhang Liang , Li Ping , Cukier Robert I. , Bu Yuxiang 
Published: December 2006

AbstractA comprehensive study is carried out using quantum chemical computation and molecular dynamics (MD) simulations to gain insight into the interaction between Ca2+ ions and the most important class of calcium channel antagonists—nifedipine. First, the chelating structures and energetic characters of nifedipine–Ca2+ in the gas phase are explored, and 25 isomers are found. The most favorable chelating mode is a tridentate one, that is, Ca2+ binds to two carbonyl O atoms and one nitryl O atom, where Ca2+ is above the plane of the three O atoms to form a pyramidal structure. Accurate geometric structures, relative stabilities, vertical and adiabatic binding energies, and charge distributions are discussed. The differences in the geometries and energies among these isomers are analyzed from the contributions of chelating sites, electrostatics and polarizations, steric repulsions, and charge distributions. The interconversions among isomers with similar geometries and energies are also investigated because of the importance of the geometric transformation in the biological system. Furthermore, certain numbers of water molecules are added to the nifedipine–Ca2+ system to probe the effect of water. A detailed study is performed on the hydrated geometries on the basis of the most stable isomer 1. Stepwise hydration can weaken the nifedipine–Ca2+ interaction, and the chelating sites of nifedipine are gradually replaced by the added water molecules. Hexacoordination is found to be the most favorable geometry no matter how many water molecules were added, which can be verified by the MD simulations. The transfer of water molecules from the inner shell to the outer shell is also supported by MD simulations of the hexahydrated complexes.
High‐frequency constant‐current power supply in noncontact energy transfer system using immittance converter
Authors: Irie Hisaichi , Yabuuchi Tomohiro 
Published: December 2006

AbstractNoncontact energy transfer systems are used in various fields in the industry. A high‐frequency constant current must be supplied to the feeder of noncontact energy transfer systems. This paper proposes a high‐frequency constant power supply for a noncontact energy transfer system using an immittance converter. When there are two or more pick‐up coils on the feeder, the output of one pick‐up coil does not affect other pick‐up coils on the feeder if the feeder current is constant. We proposed use of an immittance converter to transform the high‐frequency constant‐voltage source into a high‐frequency constant‐current source.“Immittance converter” is a combined form of “impedance‐admittance converter.” The immittance converter has input impedance that is proportional to the admittance of the load connected across output terminals. In this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant‐voltage source into a constant‐current source and a constant‐current source into a constant‐voltage source.This paper contains descriptions of the configuration of the new high‐frequency constant‐current power supply for noncontact energy transfer system, output characteristics versus excessive reactance and small frequency deviations for different values of the duty factor. The experimental results are also described. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(3): 81–89, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20438
Robust optimum design of SAW filters by the penalty function method
Authors: Tagawa Kiyoharu , Ohtani Toru , Igaki Tsutomu , Seki Syunichi , Inoue Katsumi 
Published: December 2006

AbstractIn order to increase the reliability of surface acoustic wave (SAW) filters, a robust optimum design technique is presented. The frequency response characteristics of SAW filters are governed primarily by their geometrical structures, that is, the configurations of the interdigital transducers (IDTs) and reflectors fabricated on piezoelectric substrates. To choose desirable structures of SAW filters through computer simulation, conventional design techniques utilize the equivalent circuit model of the IDT. However, they have rarely considered the accuracy of the underlying model, which may be degraded by the dispersion of the circuit parameters. In this paper, considering the errors of these parameters, the robust optimum design of SAW filters is formulated as a constrained optimization problem. Then, a penalty function method combined with an improved variable neighborhood search is proposed and applied to the problem. Computational experiments conducted on a practical design problem of a resonator type SAW filter demonstrate the usefulness of the proposed method. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(3): 45–54, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20469
Controlled Formation of Mixed‐Metal Macrocycles Using Dynamic Exchange Processes and Steric Constraints
Authors: Grote Zacharias , Scopelliti Rosario , Severin Kay 
Published: December 2006

AbstractThe exchange reaction of the trinuclear macrocycles [(C6H3iPr3)Ru(C5H3NO2)]3 (AAA) and [(cymene)Ru(C5H3NO2)]3 (BBB) has been studied. It was found that the equilibration proceeds in two steps and that the final mixture is completely dominated by the mixed‐metal macrocycles [{(C6H3iPr3)Ru}2{(cymene)Ru}(C5H3NO2)3] (AAB) and [{(C6H3iPr3)Ru}{(cymene)Ru}2(C5H3NO2)3] (ABB). The results are rationalized by assuming unfavorable steric interactions between adjacent (C6H3iPr3)Ru fragments. It is shown that interactions of this kind can be used to bias scramblingprocesses in such a way that mixed‐metal macrocycles are obtained in over 80 % yield. The structures of [{(C6Me6)Ru}{(C6H6)Ru}2(C5H3NO2)3] and [(Cp*Rh){(C6H6)Ru}2‐(C5H3NO2)3] have been determined by single‐crystal X‐ray analysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis, Structure and Reactivity of Trimethylsilyl‐Substituted Phosphametallocenes
Authors: Loschen Rebekka , Loschen Christoph , Frank Walter , Ganter Christian 
Published: December 2006

AbstractNew sterically crowded phosphaferrocene and ‐ruthenocene derivatives were synthesized via the 2,5‐bis(trimethylsilyl)phospholide anion 5. Their reactivity with regard to the exchange of the Me3Si groups for other functional groups was examined. X‐ray structures were determined for the mono‐ (6) and the 1,1′‐diphosphaferrocene (8). The activation barrier for ring–ring rotation in 8 was determined by NMR spectroscopy and supported by DFT calculations. Attempts to prepare 2,5‐difunctional phosphaferrocenes through electrophilic substitutions were unsuccessful, but yielded en route a new bidentate P,P ligand (3) and its Mo(CO)4 complex, which were both characterized by X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Transient Amino‐Hydrazino‐Carbenes: A Radical Pathway for Intramolecular 1,2‐Migration Reactions
Authors: Cattoën Xavier , Gornitzka Heinz , Tham Fook S. , Miqueu Karinne , Bourissou Didier , Bertrand Guy 
Published: December 2006

AbstractThe transient amino‐hydrazino‐carbenes 2c–e are reported to undergo intramolecular 1,2‐migration reactions that proceed through a radical pathway according to DFT calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Simultaneous determination of allantoin, hypoxanthine, xanthine, and uric acid in serum/plasma by CE
Authors: Caussé Elizabeth , Pradelles Aude , Dirat Béatrice , Negre‐Salvayre Anne , Salvayre Robert , Couderc François 
Published: December 2006

AbstractAllantoin (All) is an oxidative end product of purines in mammals. The small amount of All present in human plasma or serum results from free radical action on urate and may provide a stable marker of in vivo free radical activity. Because free radicals have been implicated in the development and progression of atherosclerosis, this study focused on the metabolic compounds of the All pathway. We propose a new fast CE (CE/UV) method for the simultaneous determination of All, uric acid (UA), hypoxanthine (HX), and xanthine (X) in human plasma. These products were quantified in the plasma of patients with chronic renal failure before hemodialysis (n = 6), patients with chronic heart failure (n = 6) and controls (n = 6). The filtered plasma were diluted ten‐fold before the direct injection in CE/UV (195 nm), which allows separating the four compounds in less than 13 min. The metabolites were detectable at concentrations of 0.3–0.6 μmol/L. The method was linear over the range 0.5–150 μmol/L for All, HX, and X and 10–1500 μmol/L for UA (r > 0.99). The analytical performance of this method is satisfactory with intra‐assay CV < 3.4%, inter‐assay CV < 5% (HX and X < 7%), and recovery (93–101%). The proposed CE‐UV method appears to be a useful tool for studying physiological and pathological changes of HX, UA, and All levels in plasma samples, the latter being a possible indicator of free radical damage in vivo.
Detection of hexamethonium‐perchlorate association complexes using NACE‐MS
Authors: Groom Carl A. , Hawari Jalal 
Published: December 2006

AbstractPerchlorate (ClO4+) and other chlorine oxide anions were observed to complex weakly with hexamethonium (1,6‐bis‐(trimethylammonium)‐hexane) in both aqueous and polar nonaqueous solvents. The resultant positively charged complexes were resolved by NACE using 2‐propanol/acetone electrolytes prior to mass spectrometric detection using an Agilent3DCE system coupled to a Bruker Esquire 3000+ quadrupole IT mass detector. Using electrokinetic injection, the method detection limit for perchlorate in nonaqueous media was 10 μg/L. The isotope patterns due to the presence of 35Cl and 37Cl in complex mass spectra allowed for unambiguous identification of perchlorate, chlorate (ClO3+), chlorite (ClO2+), and chloride (Cl+) in photoreaction samples.
Genetic analysis of human complement factor H polymorphisms
Authors: Susukida Rie , Kido Akira , Oya Masakazu , Mabuchi Tadashi 
Published: December 2006

AbstractHuman complement factor H (factor H) is polymorphic, with five previously reported FH alleles and three previously reported HF alleles (HF*A, HF*B, and HF*Q0). The relationship between the FH and HF alleles is not clear, and the genetic basis of factor H phenotypes has not yet been identified. In this study, nucleotide sequence analysis of complementary DNA (cDNA) from individuals with each HF phenotype identified seven mutated sites in the factor H gene. However, in four cases, the same cDNA sequence was observed in individuals with two different HF phenotypes. Western blotting and 2‐DE also showed that a 160 kDa protein corresponding to factor H was expressed in individuals with HF phenotypes. In addition, factor H cross‐reacting 45 and 42 kDa polypeptides were detected in individuals with HF A, HF B, or HF AB phenotypes, but not in individuals with the HF Q0 (a null allele) phenotype. Thus, HF phenotype did not correlate well with factor H gene or protein structural variation. Evidence is provided to support the hypothesis that the HF phenotypes do not correspond to polymorphism in factor H, but instead correspond to polymorphism in factor H‐related protein 1. A novel PCR‐RFLP method was developed and used to detect four polymorphisms (G257A, G1492A, A2089G, and G2881T) in the factor H gene in 54 unrelated Japanese individuals. This method could be useful for studies on genetic disease associated with these mutations.
Kohlrausch regulating function and other conservation laws in electrophoresis
Authors: Hruška Vlastimil , Gaš Bohuslav 
Published: December 2006

AbstractThe Kohlrausch regulating function (KRF) is a conservation law (conservation function), which is held in electrophoresis and which enables calculation of the so‐called adjusted concentrations of constituents. The KRF is not the only conservation function and, depending on the complexity of the electrophoretic system, other conservation laws may be obeyed having a broader range of applicability. The conservation laws are tightly related to system eigenmobilities and system zones (system peaks). In principle, no system eigenmobility is exactly zero, but in most practical cases at least one system's eigenmobility is close to zero. The existence of the close‐to‐zero eigenmobility inherently points to the existence of a conservation function and a system zone which is stationary. The stationary system zone is called injection zone, stagnant zone, water peak, or solvent dip. Electrophoretic (electromigration) systems can be divided into two types: (i) conservation systems, in which the absolute value of at least one system eigenmobility is close to zero and where at least one conservation law is obeyed and (ii) nonconservation systems, where no system eigenmobility is close to zero and no conservation law is obeyed. The paper reviews work dealing with conservation functions in electromigration, derives some “historical” conservation functions in a new way, derives several conservation functions for systems of multivalent electrolytes, and discusses electrophoretic systems that have nonconservation behavior. In some typical instances, the conservation functions are simulated by means of a dynamic simulation tool and depicted graphically.
Molecularly imprinted polymers as a tool for separation in CEC
Authors: Liu Zhao‐Sheng , Zheng Chao , Yan Chao , Gao Ru‐Yu 
Published: December 2006

AbstractMolecularly imprinted polymers (MIPs) are synthesized in the presence of a template which results in the formation of specific recognition cavities complementary to the template in shape and chemical functionality. One of the most successful application areas of MIPs is chromatographic sorbents, which are tailor‐made synthetic polymers for a given analyte. However, low efficiency of MIP columns is often observed because of slow kinetics of the template. CEC‐based MIPs are thought to improve efficiency of MIP‐based separation due to the enhanced flow dynamics of CEC. Another attractive feature is the miniaturized format of CEC, so that fewer templates or monomers for the molecular imprinting are consumed, a characteristic desired for ‘green chemistry'. The small dimensions of a capillary demand the development of novel polymer formats that can be applied to a miniaturized system. This review discusses the various formats, i.e., the micro‐ or nanoparticle, the coating and the monolith, for application in CEC as well as the use in MIP syntheses and characteristics.
Biospecific interaction (affinity) CEC and affinity nano‐LC
Authors: Okanda Fred M. , El Rassi Ziad 
Published: December 2006

AbstractThis review article is aimed at assessing the recent progress made in affinity nano‐LC and affinity CEC performed in capillaries and microchips. A variety of biospecific interactions is covered including lectin affinity, immunoaffinity, immobilized metal affinity, sugar‐based affinity, protein A affinity, protein G affinity, aptamer affinity, enzyme affinity, and other miscellanea. ACE involving affinity interaction in free solution is not covered in this review article. Also, affinity‐based separations involving chiral recognition are not the subject of this review article because they are the topic of a more specialized review article on chiral separations in this special issue. A total of 31 papers published in the period 1998–2006 have been discussed in this review article.
Two preconditioners for saddle point problems in fluid flows
Authors: de Niet A. C. , Wubs F. W. 
Published: December 2006

AbstractIn this paper two preconditioners for the saddle point problem are analysed: one based on the augmented Lagrangian approach and another involving artificial compressibility. Eigenvalue analysis shows that with these preconditioners small condition numbers can be achieved for the preconditioned saddle point matrix. The preconditioners are compared with commonly used preconditioners from literature for the Stokes and Oseen equation and an ocean flow problem. The numerical results confirm the analysis: the preconditioners are a good alternative to existing ones in fluid flow problems. Copyright © 2006 John Wiley & Sons, Ltd.
Semi‐Lagrangian semi‐implicit time‐splitting scheme for the shallow water equations
Authors: Bourchtein A. , Bourchtein L. 
Published: December 2006

AbstractTime‐splitting technique applied in the context of the semi‐Lagrangian semi‐implicit method allows the use of extended time steps mainly based on physical considerations and reduces the number of numerical operations at each time step such that it is approximately proportional to the number of the points of spatial grid. To control time growth of the additional truncation errors, the standard stabilizing correction method is modified with no penalty for accuracy and efficiency of the algorithm. A linear analysis shows that constructed scheme is stable for time steps up to 2h. Numerical integrations with actual atmospheric fields of pressure and wind confirm computational efficiency, extended stability and accuracy of the proposed scheme. Copyright © 2006 John Wiley & Sons, Ltd.
Free PSA isoforms and intact and cleaved forms of urokinase plasminogen activator receptor in serum improve selection of patients for prostate cancer biopsy
Authors: Steuber Thomas , Vickers Andrew , Haese Alexander , Kattan Michael W. , Eastham James A. , Scardino Peter T. , Huland Hartwig , Lilja Hans 
Published: January 2007

AbstractClinicians currently use simple cut‐points, such as serum prostate‐specific antigen (PSA) ≥≥4 ng/ml, to decide whether to recommend further work‐up for prostate cancer (PCa). As an alternative strategy, we evaluated multivariable models giving probabilities of a PCa diagnosis based on PSA and several circulating novel biomarkers. We measured total PSA, free PSA (fPSA), fPSA subfractions (single‐chain fPSA‐I and multichain fPSA‐N), total human glandular kallikrein 2 (hK2) and full‐length and cleaved forms of soluble urokinase plasminogen activator receptor (suPAR) in pretreatment serum from 355 men referred for prostate biopsy. Age and total PSA were combined in a “base” regression model to predict biopsy outcome. We then compared this base model to models supplemented by various combinations of circulating markers, using concordance index (AUC) to measure diagnostic discrimination. PCa prediction was significantly enhanced by models supplemented by measurements of suPAR fragments and fPSA isoforms. Addition of these markers improved bootstrap‐corrected AUC from 0.611 for a cut‐point and 0.706 for the base model to 0.754 for the full model (p = 0.005). This improved diagnostic accuracy was also seen in subanalysis of patients with PSA 2–9.99 ng/ml and normal findings on DRE (0.652 vs. 0.715, p = 0.039). In this setting, hK2 did not add diagnostic information. Measurements of individual forms of suPAR and PSA isoforms contributed significantly to discrimination of men with PCa from those with no evidence of malignancy. © 2006 Wiley‐Liss, Inc.
Naringin, a grapefruit flavanone, protects V79 cells against the bleomycin‐induced genotoxicity and decline in survival
Authors: Jagetia Abhinav , Jagetia Ganesh Chandra , Jha Shalini 
Published: December 2006

AbstractThe effect of naringin, a grapefruit flavonone was studied on bleomycin‐induced genomic damage and alteration in the survival of cultured V79 cells. Exposure of V79 cells to bleomycin induced a concentration dependent elevation in the frequency of binucleate cells bearing micronuclei (MNBNC) and a maximum number of MNBNCs were observed in the cells treated with 50 μg ml−1 bleomycin, the highest concentration evaluated. This genotoxic effect of bleomycin was reflected in the cell survival, where a concentration dependent decline was observed in the cells treated with different concentrations of bleomycin. Treatment of cells with 1 mm naringin before exposure to different concentrations of bleomycin arrested the bleomycin‐induced decline in the cell survival accompanied by a significant reduction in the frequency of micronuclei when compared with bleomycin treatment alone. The cell survival and micronuclei induction were found to be inversely correlated. The repair kinetics of DNA damage induced by bleomycin was evaluated by exposing the cells to 10 μg ml−1 bleomycin using single cell gel electrophoresis. Treatment of V79 cells with bleomycin resulted in a continuous increase in DNA damage up to 6 h post‐bleomycin treatment as evident by migration of more DNA into the tails (% tail DNA) of the comets and a subsequent increase in olive tail moment (OTM), an index of DNA damage. Treatment of V79 cells with 1 mm naringin reduced bleomycin‐induced DNA damage and accelerated DNA repair as indicated by a reduction in % tail DNA and OTM with increasing assessment time. A maximum reduction in the DNA damage was observed at 6 h post‐bleomycin treatment, where it was 5 times lower than bleomycin alone. Our study, which was conducted on the basis of antioxidant, free radical scavenging and metal chelating properties of naringin demonstrates that naringin reduced the genotoxic effects of bleomycin and consequently increased the cell survival and therefore may act as a chemoprotective agent in clinical situations. Copyright © 2006 John Wiley & Sons, Ltd.
The role of the organ microenvironment in the biology and therapy of cancer metastasis
Authors: Fidler Isaiah J. , Kim Sun‐Jin , Langley Robert R. 
Published: December 2006

AbstractBy the time of diagnosis, primary neoplasms are biologically heterogeneous and contain subpopulations of cells with different metastatic potentials. The pathogenesis of a metastasis consists of many sequential steps that must be completed to produce clinically relevant lesions. During any of these steps, tumor cells interact with host factors in the microenvironment that the tumor cells can usurp. Treatment of metastasis can be directed against tumor cells and/or microenvironmental factors that support tumor growth, such as tumor‐associated blood vessels. J. Cell. Biochem. 101: 927–936, 2007. © 2006 Wiley‐Liss, Inc.