bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Analysis of the Catalytic Combustion of Premixed Methane/Air Mixtures in Microtubes
Authors: Zhong B. J. , Jiao J. 
Published: August 2008

AbstractThe combustion characteristics and extinction limits for the catalytic combustion of a methane/air mixture in a microtube are investigated computationally using the commercial CFD code FLUENT coupled to an external subroutine DETCHEM. The effects of the microtube dimensions, conductivities of wall materials, external heat losses and flow velocity on the combustion stability, are also studied. The numerical model is set as either adiabatic or non‐adiabatic with a fixed exterior heat transfer coefficient. Numerical results indicate that thermal conductivity and wall thickness are vital to preheat the methane/air mixture through the conducting wall. Two types of extinction occur, i.e., thermal quenching and blow out. These extinction limits are characterized by wall surface temperature in the microtube and the ratio of Pt(s)/O(s).
Dividing Wall Distillation Columns: Optimization and Control Properties
Authors: Gómez‐Castro F. I. , Segovia‐Hernández J. G. , Hernández S. , Gutiérrez‐Antonio C. , Briones‐Ramírez A. 
Published: August 2008

AbstractThe optimal design of dividing wall columns is a non‐linear and multivariable problem, and the objective function used as optimization criterion is generally non‐convex with several local optimums. Considering this fact, in this paper, we studied the design of dividing wall columns using as a design tool, a multi‐objective genetic algorithm with restrictions, written in MatlabTM and using the process simulator Aspen PlusTM for the evaluation of the objective function. Numerical performance of this method has been tested in the design of columns with one or two dividing walls and with several mixtures to test the effect of the relative volatilities of the feed mixtures on energy consumption, second law efficiency, total annual cost, and theoretical control properties. In general, the numerical performance shows that this method appears to be robust and suitable for the design of sequences with dividing walls.
Effect ofcytochrome P450 3A5*3genotype on the stereoselective pharmacokinetics of amlodipine in healthy subjects
Authors: Kim Kyoung‐Ah , Park Pil‐Whan , Park Ji‐Young 
Published: August 2008

AbstractAmlodipine is a racemic mixture composed ofS‐ andR‐form and metabolized stereoselectively. Cytochrome P450 3A (CYP3A) including CYP3A5 are involved in the metabolism of amlodipine and it was reported that polymorphicCYP3A5genotype modulates the plasma levels of amlodipine and thus affect its pharmacokinetics. This study was conducted to find whether stereoselective pharmacokinetics of amlodipine was affected by the polymorphicCYP3A5genotype. Seventeen healthy subjects were genotyped forCYP3A5*3variant. After a single dose of 10‐mg amlodipine, enantiomers of amlodipine were analyzed using HPLC‐MS/MS equipped with an AGP column. Amlodipine showed stereoselective pharmacokinetics.S‐amlodipine exhibited higher plasma levels thanR‐amlodipine in both genotype groups.S‐amlodipine showed 15% higher mean peak plasma concentrations (Cmax) inCYP3A5*1/*3carriers (3.28 ng/ml) thanCYP3A5*3/*3carriers (2.85 ng/ml) (P= 0.194) andR‐amlodipine also showed 21% higherCmaxinCYP3A5*1/*3carriers (3.33 ng/ml) thanCYP3A5*3/*3carriers (2.75 ng/ml) (P= 0.114).CYP3A5*1/*3carriers also have 23 and 12% higher mean area under the time versus concentration curve ofR‐amlodipine andS‐amlodipine thanCYP3A5*3/*3carriers, respectively (forR‐amlodipine, 147.1 ng*h/ml forCYP3A5*1/*3carriers versus 121.8 ng*h/ml forCYP3A5*3/*3carriers,P= 0.234; for S‐amlodipine, 161.6 ng*h/ml forCYP3A5*1/*3carriers vs. 144.2 ng*h/ml forCYP3A5*3/*3carriers,P= 0.353). Other pharmacokinetic parameters also showed no significant difference between them. In conclusion, the present study showed that despite the evidence that amlodipine is stereoselectively metabolized,CYP3A5*3genotype did not affect stereoselective disposition of amlodipine. It provides the evidence thatCYP3A5*3genotype plays a minor role in the interindividual variability of stereoselective disposition of amlodipine in humans. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Asymmetric Michael addition of trisubstituted carbanion to nitroalkenes catalyzed by sodium demethylquinine salt in water
Authors: Chen Fu‐Xin , Shao Cheng , Liu Qian , Gong Pin , Liu Chun‐Liang , Wang Rui 
Published: August 2008

AbstractA mild method for the asymmetric synthesis of quaternary and tertiary carbon centers has been developed through Michael addition of trisubstituted carbon nucleophile to nitroalkenes catalyzed by low loading sodium demethylquinine salt in water. Chirality, 2008. © 2009 Wiley‐Liss, Inc.
Dyson's nonintersecting Brownian motions with a few outliers
Authors: Adler Mark , Delépine Jonathan , van Moerbeke Pierre 
Published: August 2008

AbstractConsider n nonintersecting Brownian particles on ℝ (Dyson Brownian motions), all starting from the origin at time t = 0 and forced to return to x = 0 at time t = 1. For large n, the average mean density of particles has its support, for each 0 < t < 1, on the interval ±√2nt(1 − t). The Airy process 𝒜(τ) is defined as the motion of these nonintersecting Brownian motions for large n but viewed from the curve 𝒞 : y = √2nt(1 − t) with an appropriate space‐time rescaling.Assume now a finite number r of these particles are forced to a different target point, say a = ρ0√n/2 > 0. Does it affect the Brownian fluctuations along the curve 𝒞 for large n? In this paper, we show that no new process appears as long as one considers points (y, t) ∈ 𝒞 such that 0 < t < (1 + ρ)−1, which is the t‐coordinate of the point of tangency of the tangent to the curve passing through (ρ0√n/2, 1). At this point the fluctuations obey a new statistics, which we call the Airy process with r outliers 𝒜(r)(τ) (in short, r‐Airy process). The log of the probability that at time τ the cloud does not exceed x is given by the Fredholm determinant of a new kernel (extending the Airy kernel), and it satisfies a nonlinear PDE in x and τ, from which the asymptotic behavior of the process can be deduced for τ → −∞. This kernel is closely related to one found by Baik, Ben Arous, and Péché in the context of multivariate statistics. © 2008 Wiley Periodicals, Inc.
On the Validity of Stokes–Einstein and Stokes–Einstein–Debye Relations in Ionic Liquids and Ionic‐Liquid Mixtures
Authors: Köddermann Thorsten , Ludwig Ralf , Paschek Dietmar 
Published: August 2008

AbstractStokes–Einstein (SE) and Stokes–Einstein–Debye (SED) relations in the neat ionic liquid (IL) [C2mim][NTf2] and IL/chloroform mixtures are studied by means of molecular dynamics (MD) simulations. For this purpose, we simulate the translational diffusion coefficients of the cations and anions, the rotational correlation times of the C(2)H bond in the cation C2mim+, and the viscosities of the whole system. We find that the SE and SED relations are not valid for the pure ionic liquid, nor for IL/chloroform mixtures down to the miscibility gap (at 50 wt % IL). The deviations from both relations could be related to dynamical heterogeneities described by the non‐Gaussian parameter α(t). If α(t) is close to zero, at a concentration of 1 wt % IL in chloroform, both relations become valid. Then, the effective radii and volumes calculated from the SE and SED equations can be related to the structures found in the MD simulations, such as aggregates of ion pairs. Overall, similarities are observed between the dynamical properties of supercooled water and those of ionic liquids.
A fast, fully automated cell segmentation algorithm for high‐throughput and high‐content screening
Authors: Fenistein D. , Lenseigne B. , Christophe T. , Brodin P. , Genovesio A. 
Published: August 2008

AbstractHigh‐throughput, high‐content screening (HT‐HCS) of large compound libraries for drug discovery imposes new constraints on image analysis algorithms. Time and robustness are paramount while accuracy is intrinsically statistical. In this article, a fast and fully automated algorithm for cell segmentation is proposed. The algorithm is based on a strong attachment to the data that provide robustness and have been validated on the HT‐HCS of large compound libraries and different biological assays. We present the algorithm and its performance, a description of its advantages and limitations, and a discussion of its range of application. © 2008 International Society for Advancement of Cytometry
Myotonic dystrophy protein kinase is expressed in embryonic myocytes and is required for myotube formation
Authors: Harmon Erin B. , Harmon Michelle L. , Larsen Tricia D. , Paulson Alicia F. , Perryman M. Benjamin 
Published: August 2008

AbstractMyotonic dystrophy (DM1) is a multi‐systemic disease caused by a triplet nucleotide repeat expansion in the 3′ untranslated region of the gene coding for myotonic dystrophy protein kinase (DMPK). The primary pathophysiology of DM1 is thought to result from RNA transport and processing defects. The function of DMPK in development or any potential role in DM1 remains unknown. Here we report a novel role for DMPK in myogenesis. We have discovered a specific expression pattern of DMPK in mouse and chick embryonic development. DMPK is expressed in postmitotic cardiac and skeletal myocytes and developmental signaling centers. During cardiac myocyte maturation, DMPK migrates from perinuclear to cellular membrane localization. Manipulating DMPK levels in cultured cardiac and skeletal myocytes has revealed a key role for DMPK in myocyte differentiation. Overexpression of DMPK induces cell rounding and apoptosis in myocytes. In addition, DMPK is necessary for myogenin expression in differentiating C2C12 myoblasts. Developmental Dynamics 237:2353–2366, 2008. © 2008 Wiley‐Liss, Inc.
Monocilia in the embryonic mouse heart suggest a direct role for cilia in cardiac morphogenesis
Authors: Slough Jennifer , Cooney Laura , Brueckner Martina 
Published: August 2008

AbstractPrimary cilia are required for signaling, chemosensing and mechanosensing in many fluid‐filled organs, thus cilia could also have a direct role in heart development. They are essential to the development of cardiac left–right (LR) asymmetry by means of their function at the embryonic organizer (node). We show that cilia are found in the mouse embryo heart at embryonic day (e) 9.5–e12.5. We demonstrate abnormal development of the endocardial cushions (ECCs) and compact myocardium (CM) in e9.5 mouse embryos with absent cilia. In contrast, hearts from embryos with abnormal LR development due to paralyzed, but structurally normal, node cilia show less severe ECC defects and normal CM. These observations suggest that a subset of cilia called cardiac cilia are required in cardiac development independently from their function in LR development. One possible function of cardiac cilia is as mechanosensors, integrating flow, cardiac function, and morphogenesis. Developmental Dynamics 237:2304–2314, 2008. © 2008 Wiley‐Liss, Inc.
Muscle development is disrupted in zebrafish embryos deficient for fibronectin
Authors: Snow Chelsi J. , Peterson Matthew T. , Khalil Andre , Henry Clarissa A. 
Published: August 2008

AbstractAfter somitogenesis, skeletal muscle precursors elongate into muscle fibers that anchor to the somite boundary, which becomes the myotome boundary. Fibronectin (Fn) is a major component of the extracellular matrix in both boundaries. Although Fn is required for somitogenesis, effects of Fn disruption on subsequent muscle development are unknown. We show that fn knockdown disrupts myogenesis. Muscle morphogenesis is more disrupted in fn morphants than in a mutant where initial somite boundaries did not form, aei/deltaD. We quantified this disruption using the two‐dimensional Wavelet‐Transform Modulus Maxima method, which uses the variation of intensity in an image with respect to the direction considered to characterize the structure in a cell lattice. We show that fibers in fn morphants are less organized than in aei/deltaD mutant embryos. Fast‐ and slow‐twitch muscle lengths are also more frequently uncoupled. These data suggest that fn may function to regulate fiber organization and limit fast‐twitch muscle fiber length. Developmental Dynamics 237:2542–2553, 2008. © 2008 Wiley‐Liss, Inc.
Zebrafish mutants with disrupted early T‐cell and thymus development identified in early pressure screen
Authors: Trede Nikolaus S. , Ota Tatsuya , Kawasaki Hirohide , Paw Barry H. , Katz Tammisty , Demarest Bradley , Hutchinson Sarah , Zhou Yi , Hersey Candace , Zapata Agustin , Amemiya Chris T. , Zon Leonard I. 
Published: August 2008

AbstractGeneration of mature T lymphocytes requires an intact hematopoietic stem cell compartment and functional thymic epithelium. We used the zebrafish (Danio rerio) to isolate mutations that affect the earliest steps in T lymphopoiesis and thymic organogenesis. Here we describe the results of a genetic screen in which gynogenetic diploid offspring from heterozygous females were analyzed by whole‐mount in situ hybridization for the expression of rag‐1. To assess immediately if a global defect in hematopoiesis resulted in the mutant phenotype, α‐embryonic globin expression was simultaneously assayed for multilineage defects. In this report, we present the results obtained with this strategy and show representative mutant phenotypes affecting early steps in T‐cell development and/or thymic epithelial cell development. We discuss the advantage of this strategy and the general usefulness of the zebrafish as a model system for vertebrate lymphopoiesis and thymic organogenesis. Developmental Dynamics 237:2575–2584, 2008. © 2008 Wiley‐Liss, Inc.
Global optimization with the PSO coupling‐type discrete gradient chaos model
Authors: Okamoto Takashi , Aiyoshi Eitaro 
Published: August 2008

AbstractIn this paper, we propose a new multiagent discrete gradient chaos model using a coupling structure which PSO has. Concretely, first, we introduce a multiagent‐type optimization model whose agents search autonomously with the discrete gradient chaos model which is the simplest dynamical global search model, and they are coupled by convective coupling. Convective coupling in this model is used to aim at overcoming of emergence of boundary crisis which is a problem of the original discrete gradient chaos model. Second, we introduce PSO coupling structure, where population drifts to the “gbest” and the “pbest”, into discrete gradient chaos model. Then, we propose “PSO coupling‐type discrete gradient chaos model” with the search strategy based on objective function's value. In this paper, our proposed models are applied to several benchmark problems. The results show that our proposed models have better global optimization ability than the original discrete gradient chaos model and PSO model. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(4): 67–75, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20563
Spatial metrics and methods for riverscapes: quantifying variability in riverine fish habitat patterns
Authors: Le Pichon Céline , Gorges Guillaume , Baudry Jacques , Goreaud François , Boët Philippe 
Published: August 2008

AbstractDefining the optimal configuration of all habitats required during a life cycle, called vital habitat, is a necessary step for effective management of riverine fishes and restoration of river habitats. Landscape ecology provides many metrics and methods to study the composition and configuration of habitats, but they need to be adapted for fishes in river environments or riverscapes. For example, hydrographic distance seems more appropriate than Euclidean distance for measuring distances between vital habitats in riverscapes. We adapted some metrics to assess habitats patterns of a threatened cyprinid species (Barbus barbus) for natural and artificial riverscapes of the Seine river, France. Composition metrics provided essential quantification of the relative abundance of the vital habitats, whereas configuration metrics were relevant to quantify their spatial arrangement and spatial relationships. Nearest‐neighbor hydrographic distance was useful to evaluate the influence of flow variability in the natural riverscape, but was not relevant to discriminate the artificial riverscape from the natural one. Conversely, a proximity index revealed high fragmentation in the artificial riverscape. Spatial habitat relationships between feeding and resting habitats, evaluated with a moving window analysis, provided a map of daily activity patches and emphasized the gaps in the biological continuity of the riverscape. The spatial metrics and methods we adapted to the particularities of the Seine river allowed us to detect natural and artificial variability in fish habitat patterns. They should help in evaluating impacts of habitat alteration and isolation and prioritize preservation and restoration policies in human‐impacted rivers. Copyright © 2008 John Wiley & Sons, Ltd.
Modelling the Effect of Inhomogeneous Compression of GDL on Local Transport Phenomena in a PEM Fuel Cell
Authors: Nitta I. , Karvonen S. , Himanen O. , Mikkola M. 
Published: August 2008

AbstractThe effects of inhomogeneous compression of gas diffusion layers (GDLs) on local transport phenomena within a polymer electrolyte membrane (PEM) fuel cell were studied theoretically. The inhomogeneous compression induced by the rib/channel structure of the flow field plate causes partial deformation of the GDLs and significantly affects component parameters. The results suggest that inhomogeneous compression does not significantly affect the polarisation behaviour or gas–phase mass transport. However, the effect of inhomogeneous compression on the current density distribution is evident. Local current density under the channel was substantially smaller than that under the rib when inhomogeneous compression was taken into account, while the current density distribution was fairly uniform for the model which excluded the effect of inhomogeneous compression. This is caused by the changes in the selective current path, which is determined by the combination of conductivities of components and contact resistance between them. Despite the highly uneven current distribution and variation in material parametres as a function of GDL thickness, the temperature profile was relatively even over the active area for both the modelled cases, contrary to predictions in previous studies. However, an abnormally high current density significantly accelerates deterioration of the membrane and is critical in terms of cell durability. Therefore, fuel cells should be carefully designed to minimise the harmful effects of inhomogeneous compression.
Modelling of Reaction and Diffusion Processes in a High‐surface‐area Biofuel Cell Electrode Made of Redox Polymer‐grafted Carbon
Authors: Tamaki T. , Ito T. , Yamaguchi T. 
Published: August 2008

AbstractA mathematical model considering reaction and diffusion processes in biofuel cells, such as enzyme reactions, apparent electron diffusion in the redox polymer, and diffusion of a substrate in a redox polymer film, verified the effectiveness of a high‐surface‐area biofuel cell electrode with a thin, grafted redox polymer layer. The model calculation shows that the rate‐limiting step of apparent electron diffusion can be overcome by using the electrode with a thin redox polymer, even when the redox polymer used has a low apparent electron diffusion coefficient. In the electrode, increase in the second‐order rate constant for the reaction between an enzyme and a mediator above a certain value does not increase the current density, and thus the mediator used in the electrode should have an adequate second‐order rate constant and a more negative redox potential. In addition, increase in the turnover rate of the enzyme and the surface coverage of the enzyme allows an increase in the current density; the surface coverage of the enzyme has the most influence. Based on these calculations, it is important to realise high‐surface‐area electrodes with a thin redox polymer, and with high enzyme loading.
Ligand‐Free Copper‐Catalyzed Arylation of Imidazole and N,N′‐Carbonyldiimidazole, and Microwave‐Assisted Synthesis of N‐Aryl‐1H‐imidazoles
Authors: Yang Xiao‐Dong , Li Liang , Zhang Hong‐Bin 
Published: August 2008

AbstractMicrowave‐assisted arylation of 1H‐imidazoles and N,N′‐carbonyldiimidazole under ligand‐free copper‐mediated conditions in tetraethyl orthosilicate is reported. Valuable evidence for understanding of the Cu‐catalyzed mechanism of the Ullmann reaction is also presented.
Intramolecular Wittig Reaction: A New Synthesis of (S)‐Pyrrolam A
Authors: Majik Mahesh S. , Parameswaran Perunninakulath S. , Tilve Santosh G. 
Published: August 2008

AbstractA straightforward synthesis of (S)‐pyrrolam A is described. The synthesis involves in situ generation of the phosphorane 3, followed by an intramolecular Wittig reaction to furnish (S)‐pyrrolam A.
Kopsine and Danuphylline Alkaloids from Kopsia. Biomimetic Partial Synthesis of Danuphylline B
Authors: Lim Kuan‐Hon , Low Yun‐Yee , Tan Guan‐Huat , Kam Toh‐Seok , Lim Tuck‐Meng 
Published: August 2008

AbstractTwo new indole alkaloids, 12‐methoxykopsine (6) and danuphylline B (7), were obtained from the leaf extract of the Malayan Kopsia species, K. arborea, and their structures established by spectroscopic analysis. An electrochemically‐mediated partial synthesis of the ring‐opened alkaloid, danuphylline B from the hexacyclic alkaloid, methyl N(1)‐de(methoxycarbonyl)chanofruticosinate was carried out.
Synthesis, Characterization, Thermal Decomposition, and Kinetic Studies of Binuclear Sulfur‐Coordinated Tungsten(V) Complexes with Piperidine‐1‐carbodithioate
Authors: Lozano Rafael , de Jesús Fernando , Cano de Santayana Mercedes , Lozano M. Carmen 
Published: August 2008

AbstractWe describe the synthesis, characterization by IR and electronic spectra, magnetic susceptibility measurements, analytical data, kinetic study by differential‐scanning calorimetry, and thermogravimetric analysis of the thermal decomposition under N2 of the adducts 2–7 with pyridine or substituted pyridines of bis(piperidine‐1‐carbodithioato‐κS,κS′)di‐μ‐thioxodithioxoditungsten(V) (1), to which the general formula [W2B2(pipCS2)2S2(μ‐S)2] is assigned (pipCS2=piperidine‐1‐carbodithioato and B=pyridine (py), 3‐methylpyridine (3‐Mepy), 4‐methylpyridine (4‐Mepy), 3,5‐dimethylpyridine (3,5‐Me2py), pyridin‐3‐amine (3‐pyNH2), and pyridin‐4‐amine (4‐pyNH2)). For the endothermic process of loss of the coordinated base B, we calculated activation energies with a method reported previously by us; the mechanism and pre‐exponential Arrhenius factor of this reaction were also determined. A relationship between the pyridines' basicity, IR and electronic spectral data, and activation energies was established.