bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual‐Amplification of Antigen–Antibody Interactions via Backfilling Gold Nanoparticles on (3‐Mercaptopropyl) Trimethoxysilane Sol‐Gel Functionalized Interface
Authors: An Haizhen , Yuan Ruo , Tang Dianping , Chai Yaqin , Li Na 
Published: February 2007

AbstractA new dual‐amplification strategy of electrochemical signaling from antigen–antibody interactions was proposed via backfilling gold nanoparticles on (3‐mercaptopropyl) trimethoxysilane sol‐gel (MPTS) functionalized interface. The MPTS was employed not only as a building block for the electrode surface modification but also as a matrix for ligand functionalization with first amplification. The second signal amplification strategy introduced in this study was based on the backfilling immobilization of nanogold particles to the immunosensor surface. Several coupling techniques, such as with nanogold but not MPTS or with MPTS but not nanogold, were investigated for the determination of carcinoembryonic antigen (CEA) as a model, and a very good result was obtained with nanogold and MPTS coupling immunosensor. With the noncompetitive format, the formation of the antigen–antibody complex by a simple one‐step immunoreaction between the immobilized anti‐CEA and CEA in sample solution introduced membrane potential change before and after the antigen–antibody interaction. Under optimal conditions, the proposed immunosensor exhibited a good electrochemical behavior to CEA in a dynamic concentration range of 4.4 to 85.7 ng/mL with a detection limit of 1.2 ng/mL (at 3 δ). Moreover, the precision, reproducibility and stability of the as‐prepared immunosensor were acceptable. Importantly, the proposed methodology would be valuable for diagnosis and monitoring of carcinoma and its metastasis.
Stereoselective determination of hydroxychloroquine and its metabolites in human urine by liquid‐phase microextraction and CE
Authors: de Oliveira Anderson Rodrigo Moraes , Cardoso Carmen Dickow , Bonato Pierina Sueli 
Published: February 2007

AbstractLiquid‐phase microextraction based on polypropylene hollow fibers and CE were applied for the chiral determination of hydroxychloroquine (HCQ) and its metabolites (desethylchloroquine, DCQ; desethylhydroxychloroquine, DHCQ; bisdesethylchloroquine, BDCQ) in human urine. The analytes were extracted from 3 mL of urine spiked with the internal standard (metoprolol) and alkalinized with 250 μL of 2 M NaOH. The analytes were extracted into 1‐octanol impregnated in the pores of the hollow fiber, and into an acid acceptor solution inside the hollow fiber. The electrophoretic separations were carried out in 100 mmol/L Tris buffer (pH adjusted to 9.0 with phosphoric acid) containing 1% w/v S‐β‐CD and 30 mg/mL HP‐β‐CD with a constant voltage of +18 kV. The method was linear over the concentration range of 10–1000 ng/mL for each HCQ stereoisomer and 21–333 ng/mL for each metabolite stereoisomer. Within‐day and between‐day assay precision and accuracy for the analytes were studied at three concentration levels for each stereoisomer and were lower than 15%. The developed method was applied for the determination of the cumulative urinary excretion of HCQ, DCQ, and DHCQ after oral administration of rac‐HCQ to a health volunteer. The results obtained are in agreement with previous literature data.
Pseudodynamic response of torsionally unbalanced two‐storey test structure
Authors: Bousias S. N. , Fardis M. N. , Spathis A.‐L. , Kosmopoulos A. J. 
Published: February 2007

AbstractTwo one‐way eccentric, two‐storey, one‐by‐one‐bay reinforced concrete (RC) structures are pseudodynamically tested under unidirectional ground motions. Theoretical considerations about the effect of torsional coupling on modal periods and shapes agree with modal results of the test structure, considering member stiffness is equal to the secant stiffness to yielding in skew‐symmetric bending. Modal periods of such an elastic structure are in fair agreement with effective periods inferred from the measured response at the beginning of a test of a thoroughly cracked structure and at the end of the test. A time‐varying stiffness matrix and a non‐proportional damping matrix fitted to the test results may be used to reproduce the measured response approximately by modal superposition and identify the role of the four time‐varying modes. Flexible side columns sustained very large drift demands simultaneously in the two transverse directions and suffered significant but not heavy, damage at lap‐splices. RC‐jacketing of the flexible side columns practically eliminated the static eccentricity between the floor centres of twist and mass as well as the torsional response. Inelastic time‐history analysis with point‐hinge member models, using as elastic stiffness the secant stiffness to yielding and neglecting post‐ultimate‐strength cyclic degradation of resistance in members with plain bars and poor detailing, predicted fairly well the response until the peak displacements and member deformations occurred. After that, it underestimated displacement peaks and the lengthening of the apparent period and missed the gradual drifting of the response towards a permanent offset. Copyright © 2007 John Wiley & Sons, Ltd.
Equivalent force control method for generalized real‐time substructure testing with implicit integration
Authors: Wu Bin , Wang Qianying , Benson Shing P. , Ou Jinping 
Published: February 2007

AbstractThis paper presents a new method, called the equivalent force control method, for solving the nonlinear equations of motion in a real‐time substructure test using an implicit time integration algorithm. The method replaces the numerical iteration in implicit integration with a force‐feedback control loop, while displacement control is retained to control the motion of an actuator. The method is formulated in such a way that it represents a unified approach that also encompasses the effective force test method. The accuracy and effectiveness of the method have been demonstrated with numerical simulations of real‐time substructure tests with physical substructures represented by spring and damper elements, respectively. The method has also been validated with actual tests in which a Magnetorheological damper was used as the physical substructure. Copyright © 2007 John Wiley & Sons, Ltd.
Mobile radio bi‐dimensional large‐scale fading modelling with site‐to‐site cross‐correlation
Authors: Fraile Rubén , Monserrat José F. , Gozálvez Javier , Cardona Narcís 
Published: February 2007

AbstractWireless communication simulations are generally conducted using one‐dimensional models for large‐scale fading. While simple and with low computational costs, these models cannot produce correlated fading values for mobiles that are in nearby positions. To overcome this limitation, this paper presents a novel bi‐dimensional large‐scale fading model which introduces the spatial correlation present in real systems. Besides, it is also able to model the non‐negligible cross‐correlation among signals coming from different sites. Copyright © 2007 John Wiley & Sons, Ltd.
A simplified v2–f model for near‐wall turbulence
Authors: Rahman M. M. , Siikonen T. 
Published: February 2007

AbstractA simplified version of the v2–f model is proposed that accounts for the distinct effects of low‐Reynolds number and near‐wall turbulence. It incorporates modified Cε(1,2) coefficients to amplify the level of dissipation in non‐equilibrium flow regions, thus reducing the kinetic energy and length scale magnitudes to improve prediction of adverse pressure gradient flows, involving flow separation and reattachment. Unlike the conventional v2–f, it requires one additional equation (i.e. the elliptic equation for the elliptic relaxation parameter fµ) to be solved in conjunction with the k–ε model. The ${\bar{v}}^2$ scaling is evaluated from k in collaboration with an anisotropic coefficient Cv and fµ. Consequently, the model needs no boundary condition on ${\bar{v}}^2$ and avoids free stream sensitivity. The model is validated against a few flow cases, yielding predictions in good agreement with the direct numerical simulation (DNS) and experimental data. Copyright © 2007 John Wiley & Sons, Ltd.
Acoustic upwinding for sub‐ and super‐sonic turbulent channel flow at low Reynolds number
Authors: de Lange H. C. 
Published: February 2007

AbstractA recently developed asymmetric implicit fifth‐order scheme with acoustic upwinding for the spatial discretization for the characteristic waves is applied to the fully compressible, viscous and non‐stationary Navier–Stokes equations for sub‐ and super‐sonic, mildly turbulent, channel flow (Reτ=360). For a Mach number of 0.1, results are presented for uniform (323, 643 and 1283) and non‐uniform (expanding wall‐normal, 323 and 643) grids and compared to the (incompressible) reference solution found in (J. Fluid. Mech. 1987; 177:133–166). The results for uniform grids on 1283 and 643 nodes show high resemblance with the reference solution. Expanding grids are applied on 643‐ and 323‐node grids. The capability of the proposed technique to solve compressible flow is first demonstrated by increasing the Mach number to 0.3, 0.6 and 0.9 for isentropic flow on the uniform 643‐grid. Next, the flow speed is increased to Ma=2. The results for the isothermal‐wall supersonic flows give very good agreement with known literature results. The velocity field, the temperature and their fluctuations are well resolved. This means that in all presented (sub‐ and super‐sonic) cases, the combination of acoustic upwinding and the asymmetric high‐order scheme provides sufficient high wave‐number damping and low wave‐number accuracy to give numerically stable and accurate results. Copyright © 2007 John Wiley & Sons, Ltd.
The pricing of electricity futures: Evidence from the European energy exchange
Authors: Wilkens Sascha , Wimschulte Jens 
Published: February 2007

AbstractThis study investigates the pricing of electricity futures at the European Energy Exchange (EEX) over the period 2002 through 2004. To calculate theoretical contract values, the reduced‐form models of J. J. Lucia and E. S. Schwartz (2002) are used, and a thorough empirical analysis by means of an out‐of‐sample test is conducted for both one‐ and two‐factor models, incorporating a constant non‐zero price of risk. Although the models are proven to capture all basic spot market characteristics and provide an accurate in‐the‐sample fit to observed futures prices, the forecasting performance is subject to biases. For instance, it was found that the relative mispricing depends on both the spot price level and the remaining time‐to‐maturity of the futures contracts. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:387–410, 2007
The information content of implied volatility in light of the jump/continuous decomposition of realized volatility
Authors: Giot Pierre , Laurent Sébastien 
Published: February 2007

AbstractIn the framework of encompassing regressions, the information content of the jump/continuous components of historical volatility is assessed when implied volatility is included as an additional regressor. The authors' empirical application focuses on daily and intradaily data for the S&P100 and S&P500 indexes, and daily data for the associated VXO and VIX implied volatility indexes. The results show that the total explanatory power of the encompassing regressions barely changes when the jump/continuous components are included, although the weekly and monthly continuous components are usually significant. This evidence supports the view that implied volatility has very high information content, even when extended decompositions of past realized volatility are used. Moreover, adding GARCH‐type volatility forecasts in the regressions confirms these results. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:337–359, 2007
Involvement of P2X4and P2Y12receptors in ATP‐induced microglial chemotaxis
Authors: Ohsawa Keiko , Irino Yasuhiro , Nakamura Yasuko , Akazawa Chihiro , Inoue Kazuhide , Kohsaka Shinichi 
Published: February 2007

AbstractWe previously reported that extracellular ATP induces membrane ruffling and chemotaxis of microglia and suggested that their induction is mediated by the Gi/o‐protein coupled P2Y12receptor (P2Y12R). Here we report discovering that the P2X4receptor (P2X4R) is also involved in ATP‐induced microglial chemotaxis. To understand the intracellular signaling pathway downstream of P2Y12R that underlies microglial chemotaxis, we examined the effect of two phosphatidylinositol 3′‐kinase (PI3K) inhibitors, wortmannin, and LY294002, on chemotaxis in a Dunn chemotaxis chamber. The PI3K inhibitors significantly suppressed chemotaxis without affecting ATP‐induced membrane ruffling. ATP stimulation increased Akt phosphorylation in the microglia, and the increase was reduced by the PI3K inhibitors and a P2Y12R antagonist. These results indicate that P2Y12R‐mediated activation of the PI3K pathway is required for microglial chemotaxis in response to ATP. We also found that the Akt phosphorylation was reduced when extracellular calcium was chelated, suggesting that ionotropic P2X receptors are involved in microglial chemotaxis by affecting the PI3K pathway. We therefore tested the effect of various P2X4R antagonists on the chemotaxis, and the results showed that pharmacological blockade of P2X4R significantly inhibited it. Knockdown of the P2X4receptor in microglia by RNA interference through the lentivirus vector system also suppressed the microglial chemotaxis. These results indicate that P2X4R as well as P2Y12R is involved in ATP‐induced microglial chemotaxis. © 2007 Wiley‐Liss, Inc.
Variations in sediment sources and yields in the Finger Lakes and Catskills regions of New York
Authors: Nagle Gregory N. , Fahey Timothy J. , Ritchie Jerry C. , Woodbury Peter B. 
Published: February 2007

AbstractThe proportional contributions of stream bank and surface sources to fine sediment loads in watersheds in New York State were quantified with uncertainty analysis. Eroding streamside glacial drift, including glaciolacustrine deposits, were examined to help explain variations in the proportional contributions made by bank erosion. Sediment sources were quantified by comparing concentrations of the bomb‐derived radionuclide 137Cs in fluvial sediment with sediment from potential source areas such as agricultural soils, forest soils and stream banks.To compare sediment sources in streams containing abundant deposits of fine‐grained glacial drift with watersheds that lacked moderate or extensive streamside deposits, samples were taken from 15 watersheds in the region. The mean contribution of bank erosion to sediment loads in the six streams with glaciolacustrine deposits was 60% (range 46–76%). The proportional contribution of bank erosion was also important in one stream lacking glaciolacustrine deposits (57%) but was less important in the remainder, with contributions ranging from 0 to 46%. Data from this study on the varying contributions of bank erosion and data from past studies of sediment yield in 15 watersheds of New York State suggest that eroding streamside glacial deposits dominate sediment yield in many watersheds. In other watersheds, past impacts to streams, such as channelization, have also resulted in high levels of bank erosion. Copyright © 2007 John Wiley & Sons, Ltd.
Gaussian induced dipole polarization model
Authors: Elking Dennis , Darden Tom , Woods Robert J. 
Published: February 2007

AbstractA new induced dipole polarization model based on interacting Gaussian charge densities is presented. In contrast to the original induced point dipole model, the Gaussian polarization model is capable of finite interactions at short distances. Aspects of convergence related to the Gaussian model will be explored. The Gaussian polarization model is compared with the damped Thole‐induced dipole model and the point dipole model. It will be shown that the Gaussian polarization model performs slightly better than the Thole model in terms of fitting to molecular polarizability tensors. An advantage of the model based on Gaussian charge distribution is that it can be easily generalized to other multipole moments and provide effective damping for both permanent electrostatic and polarization models. Finally, a method of parameterizing polarizabilities is presented. This method is based on probing a molecule with point charges and fitting polarizabilities to electrostatic potential. In contrast to the generic atom type polarizabilities fit to molecular polarizability tensors, probed polarizabilities are significantly more accurate in terms of reproducing molecular polarizability tensors and electrostatic potential, while retaining conformational transferability. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Wavelet transform analysis of ab initio molecular dynamics simulation: Application to core‐excitation dynamics of BF3
Authors: Otsuka Takao , Nakai Hiromi 
Published: February 2007

AbstractWe propose a novel analysis method of ab initio molecular dynamics (AIMD) simulation using a continuous wavelet transform (c‐WT) technique. The c‐WT technique, one of the time‐frequency signal analysis methods, provides a clear view of the dynamical information in time developments. Combined with the auto‐correlation function of velocity by AIMD simulation, c‐WT analysis enables us to well understand dynamical distribution, such as the vibrational properties following a change of electronic structure in a molecular system. As a practical application, AIMD simulation of core‐excited BF3 (B1s → 2a) is illustrated. AIMD simulation leads to the change of vibrational motion as well as structural deformation by core‐excitation. The c‐WT analysis clarifies the relationship between structural deformation and the related significant vibrational modes in core‐excitation within 50 fs. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Combined DFT, QCISD(T), and G2 mechanism investigation for the reactions of carbon monophosphide CP with unsaturated hydrocarbons allene CH2CCH2 and methylacetylene CH3CCH
Authors: Zhao YAn‐Li , Kan Wei , Zhong Hua , Yu Hai‐Tao , Fu Hong‐Gang 
Published: February 2007

AbstractThe possible reaction product distribution and mechanism of carbon monophosphide CP with unsaturated hydrocarbons allene CH2CCH2 and methylacetylene CH3CCH are investigated at the B3LYP/6‐311+G(d,p), QCISD(T)/6‐311++G(2df,2p), and G2 levels of theory. Corresponding reactants, products, intermediates, and interconversion and dissociation transition states are located on the reaction potential energy profiles. Computation results show that in the reaction of CP with CH2CCH2 the dominant reaction product should be species CH2CCHCP. Also, we can suggest species HCCCH2CP as a secondary reaction product despite of only minor contribution to reaction products. In the reaction of CP with CH3CCH, the primary and secondary products are suggested to be two important molecules HCCCP and CH3CCCP, respectively. The predicted mechanisms for the two reactions are not in parallel with the reactions of CN with allene CH2CCH2 and methylacetylene CH3CCH given in previous studies. The present calculations provide some useful information for future possible experimental isolation and observation for some interesting unsaturated carbon–phosphorus‐bearing species. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Global minimum structure searches via particle swarm optimization
Authors: Call Seth T. , Zubarev Dmitry Yu. , Boldyrev Alexander I. 
Published: February 2007

AbstractNovel implementation of the evolutionary approach known as particle swarm optimization (PSO) capable of finding the global minimum of the potential energy surface of atomic assemblies is reported. This is the first time the PSO technique has been used to perform global optimization of minimum structure search for chemical systems. Significant improvements have been introduced to the original PSO algorithm to increase its efficiency and reliability and adapt it to chemical systems. The developed software has successfully found the lowest‐energy structures of the LJ26 Lennard‐Jones cluster, anionic silicon hydride Si2H, and triply hydrated hydroxide ion OH− (H2O)3. It requires relatively small population sizes and demonstrates fast convergence. Efficiency of PSO has been compared with simulated annealing, and the gradient embedded genetic algorithm. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
A semiempirical approach to the intra‐phycocyanin and inter‐phycocyanin fluorescence resonance energy‐transfer pathways in phycobilisomes
Authors: Matamala Adelio R. , Almonacid Daniel E. , Figueroa Maximiliano F. , Martínez‐oyanedel JosÉ , Bunster Marta C. 
Published: February 2007

AbstractA semiempirical methodology to model the intra‐phycocyanin and inter‐phycocyanin fluorescence resonance energy‐transfer (FRET) pathways in the rods of the phycobilisomes (PBSs) from Fremyella diplosiphon is presented. Using the Förster formulation of FRET and combining experimental data and PM3 calculation of the dipole moments of the aromatic portions of the chromophores, transfer constants between pairs of chromophores in the phycocyanin (PC) structure were obtained. Protein docking of two PC hexamers was used to predict the optimal distance and axial rotation angle for the staked PCs in the PBSs' rods. Using the distance obtained by the docking process, transfer constants between pairs of chromophores belonging to different PC hexamers were calculated as a function of the angle of rotation. We show that six preferential FRET pathways within the PC hexameric ring and 15 pathways between hexamers exist, with transfer constants consistent with experimental results. Protein docking predicted the quaternary structure for PCs in rods with inter‐phycocyanin distance of 55.6 Å and rotation angle of 20.5°. The inter‐phycocyanin FRET constant between chromophores at positions β155 is maximized at the rotation angle predicted by docking revealing the crucial role of this specific inter‐phycocyanin channel in defining the complete set of FRET pathways in the system. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Array files for computational chemistry: MP2 energies
Authors: Ford Alan R. , Janowski Tomasz , Pulay Peter 
Published: February 2007

AbstractA simple message‐passing implementation for distributed disk storage, called array files (AF), is described. It is designed primarily for parallelizing computational chemistry applications but it should be useful for any application that handles large amounts of data stored on disk. AF allows transparent distributed storage and access of large data files. An AF consists of a set of logically related records, i.e., blocks of data. It is assumed that the records have the typical dimension of matrices in quantum chemical calculations, i.e., they range from 0.1 to ∼32 MB in size. The individual records are not striped over nodes; each record is stored on a single node. As a simple application, second‐order Møller‐Plesset (MP2) energies have been implemented using AF. The AF implementation approaches the efficiency of the hand‐coded program. MP2 is relatively simple to parallelize but for more complex applications, such as Coupled Cluster energies, the AF system greatly simplifies the programming effort. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007.