bluuebunny/crossref_metadata_2025_split huggingface dataset:
Binding kinetics of magnetic nanoparticles on latex beads studied by magnetorelaxometry
Authors: Eberbeck D. , Bergemann Ch. , Hartwig S. , Steinhoff U. , Trahms L. 
Published: October 2004

AbstractA system of magnetic nanoparticles (MNPs) and modified latex spheres was used serving as a model for studying binding reactions. The binding of MNPs on latex is estimated by the change of the magnetic relaxation properties of the MNP measured by a SQUID‐based magnetorelaxometry measurement system. By fitting of subsequently recorded relaxation curves, the kinetics of the binding reactions, i.e. the evolution of the fraction of bound MNPs, was extracted. The signal of bound MNPs scales linearly with the concentration of latex beads. For low latex concentrations the kinetics are described by a simple aggregation model, providing information about the density and probability of bindings to the target surface. Copyright © 2004 John Wiley & Sons, Ltd.
Study of the structure and stability of cobalt nanoparticles for ferrofluidic applications
Authors: Rudenkiy S. , Frerichs M. , Voigts F. , Maus‐Friedrichs W. , Kempter V. , Brinkmann R. , Matoussevitch N. , Brijoux W. , Bönnemann H. , Palina N. , Modrow H. 
Published: October 2004

AbstractWe present X‐ray absorption spectroscopy (XAS) data, ultraviolet photoelectron spectra (HeI) and metastable impact electron spectra (MIES) of cobalt nanoparticles (typically 4 to 10 nm), prepared by Co2(CO)8 thermolysis and pre‐stabilized by smooth oxidation. We find that the particles consist of a core–shell system with a dominantly f.c.c. core and a shell in which CoC and CoO coordination is likely to occur. This corresponds well to the results from electron spectroscopy, that stabilization occurs via formation of (CoCOx) and (CoO) groups formed during the oxidation procedure and appears sensitive to the reaction conditions. Peptization of the pre‐stabilized particles with KorantinSH surrounds the particles with a dense organic shell, stable up to about 250°C. The carbonic acid molecules of the shell are oriented predominantly perpendicular to the surface of the particles, their carboxyl functional group linking the shell with the cobalt particles. This result is also supported by the XAS data, where it is observed that, during peptization, CoC coordination is partly replaced by CoO coordination. In order to arrive at these statements, auxiliary measurements on bare and gas‐exposed cobalt films, also reported here, were required. Copyright © 2004 John Wiley & Sons, Ltd.
Simulation of a ferrofluid‐supported linear electrical machine
Authors: Nethe Arnim , Scholz Thomas , Stahlmann Hanns‐Dietrich 
Published: October 2004

AbstractThe force magnification of ferrofluids used in the airgap between the two acting magnets in electrical machines has been investigated with the theoretical method of orthogonal expansion. This theoretical substantiation is necessary for a comprehensive judgement of the measurements on a ferrofluid‐supported electric motor. The method itself and the results are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Distribution of olfactory epithelium in the primate nasal cavity: Are microsmia and macrosmia valid morphological concepts?
Authors: Smith Timothy D. , Bhatnagar Kunwar P. , Tuladhar Praphul , Burrows Annie M. 
Published: October 2004

AbstractThe terms “microsmatic” and “macrosmatic” are used to compare species with greater versus lesser olfactory capabilities, such as carnivores compared to certain primates. These categories have been morphologically defined based on the size of olfactory bulb and surface area of olfactory epithelium in the nasal fossa. The present study examines assumptions regarding the morphological relationship of bony elements to the olfactory mucosa, the utility of olfactory epithelial surface area as a comparative measurement, and the utility of the microsmatic concept. We examined the distribution of olfactory neuroepithelium (OE) across the anteroposterior length of the nasal fossa (from the first completely enclosed cross‐section of the nasal fossa to the choanae) in the microsmatic marmoset (Callithrix jacchus) compared to four species of nocturnal strepsirrhines (Otolemur crassicaudatus, O. garnetti, Microcebus murinus, and Cheirogaleus medius). Adults of all species were examined and infant C. jacchus, O. crassicaudatus, M. murinus, and C. medius were also examined. All specimens were serially sectioned in the coronal plane and prepared for light microscopic study. Distribution of OE across all the turbinals, nasal septal surfaces, and accessory spaces of the nasal chamber was recorded for each specimen. The right nasal fossae of one adult C. jacchus and one neonatal M. murinus were also three‐dimensionally reconstructed using Scion Image software to reveal OE distribution. Findings showed OE to be distributed relatively more anteriorly in adult C. jacchus compared to strepsirrhines. It was also distributed more anteriorly along the nasal septal walls and recesses in neonates than adults. Our findings also showed that OE surface area was not a reliable proxy for receptor neuron numbers due to differing OE thickness among species. Such results indicate that nasal cavity morphology must be carefully reconsidered regarding traditional functional roles (olfaction versus air conditioning) assigned to various nasal cavity structures. At present, the microsmatic concept itself lacks a basis in nasal chamber morphology, since OE may have varying patterns of distribution among different primates. © 2004 Wiley‐Liss, Inc.
SB‐236057: Critical window of sensitivity study and embryopathy of a potent musculoskeletal teratogen
Authors: Augustine‐Rauch Karen A. , Zhang Qin J. , Posobiec Lorraine , Mirabile Rosanna , DeBoer Lisa S. , Solomon Howard M. , Wier Patrick J. 
Published: October 2004

AbstractBACKGROUNDSB‐236057 is a potent skeletal teratogen in rodents and rabbits. The study objective was to identify the critical developmental window of compound sensitivity and to characterize the early onset of SB‐236057 embryopathy.METHODSSB‐236057 was orally administered to Sprague Dawley dams at 100 mg/kg/day on days 6–7, 8–11, 12–14, or 15–17 postcoitus (pc). The critical window of sensitivity was identified to occur between days 8–11 pc. Dams were then dosed on days 8–11 pc and embryos were evaluated by histochemical procedures on days 11, 13, or 15 pc.RESULTSAxial malformations were evident by day 11 pc. Analysis of the cartilaginous skeleton revealed missing posterior axial skeletal elements. However, only about one‐third of the malformed fetuses exhibited obvious rib and vertebrae abnormalities, and none of the affected fetuses exhibited abnormal appendicular skeletal elements. Expression pattern of sonic hedgehog in the notochord and floor plate was not affected, suggesting ventral midline signaling was not disrupted. Histological analysis demonstrated hypoplastic and/or missing musculature in proximity to the ribs and vertebrae. Caspase 3 analysis revealed no increases in apoptotic cells in the musculature. Confocal analysis of the limbs demonstrated truncated peripheral nerve formation and shortening of the appendicular musculature.CONCLUSIONSSB‐236057 is speculated to alter paraxial mesoderm programming. Many of the skeletal malformations may be caused secondarily from musculature abnormalities, suggesting that the myotome may be particularly sensitive to the compound. Furthermore, the finding that peripheral nerve trajectories were altered along the axis and in the limb suggests that SB‐236057 may alter early embryonic signaling pathways necessary for neuronal differentiation/axonal guidance that occur subsequently in embryo‐fetal development. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Unexpected distribution of immobilized microorganisms within alginate beads
Authors: Zohar‐Perez C. , Chet I. , Nussinovitch A. 
Published: October 2004

AbstractImmobilization refers to the prevention of free cell movement by natural or artificial means. It has always been assumed that immediately after an immobilization procedure is performed, cells are distributed homogeneously in the beads that entrap them. However, in this study, Escherichia coli and Trichoderma asperellum distribution in alginate‐gel beads was found to be nonhomogenous. In fact, there was a greater presence of cells on the surface of the alginate beads than in their cores. © 2004 Wiley Periodicals, Inc.
A liquid chromatography–mass spectrometry method for the quantiﬁcation of both etoricoxib and valdecoxib in human plasma
Authors: Werner Ulrike , Werner Dierk , Hinz Burkhard , Lambrecht Christoph , Brune Kay 
Published: October 2004

AbstractA practicable and selective liquid chromatography–mass spectrometry assay for the determination of two cyclooxygenase‐2 inhibitors, etoricoxib and valdecoxib, in human plasma is presented. The analytical technique is based on reversed‐phase high‐performance liquid chromatography (HPLC) coupled to atmospheric pressure chemical ionisation (APCI) mass spectrometry (Finnigan Mat LCQ ion trap). Mass analysis was performed in the positive ion mode. The ion trap was operated in the tandem MS mode (MS2) and the transitions of etoricoxib (m/z 359.2 → 280.3) and valdecoxib (m/z 315.1 → 235.1) were followed by selected reaction monitoring. Retention times of etoricoxib and valdecoxib were 1.05 and 1.08 min, respectively. The method was validated over a linear range 10–2500 and 5–1000 µg/L using the other substrate as internal standard. After validation, the method was used to study the pharmacokinetic proﬁle of etoricoxib or valdecoxib in a healthy volunteer after administration of a single oral dose (valdecoxib, 20 mg; etoricoxib, 90 mg). The presented method was sufﬁcient to cover more than 90% of the area under the plasma concentration time curve. Copyright © 2004 John Wiley & Sons, Ltd.
Stabilization of Acrylic Esters
Authors: Becker H. , Vogel H. 
Published: October 2004

AbstractAcrylic acid (AA) and its esters are monomers which can easily be polymerized. In order to avoid the unintentional polymerization during the manufacture and storage, the acrylic esters are stored under air‐atmosphere to which 15 ppm (g g–1) hydroquinone monomethylether (MeHQ) has been added. The consumption of the stabilizers, oxygen (O2) and MeHQ, play an important role in the prognosis of the stability of the monomers. In earlier works the O2/MeHQ‐consumption of acrylic acid during the inhibition period without radical‐starter‐addition was examined [1]. In this paper it could be shown that the examinations on acrylic acid are not transferable to different acrylic esters. The O2‐consumption rates in the acrylic esters are approximately ten times smaller than in acrylic acid, depending on temperature and monomer. The inhibition periods of the acrylic esters are about the factor ten greater in comparison to acrylic acid.A correlation between the concentration of the C=C double bond in the esters and the O2‐consumption is possible with the measurements of the O2‐consumption in the different acrylic esters as a function of temperature. The O2‐consumption of any acrylic ester can be calculated in this way on the basis of the C=C double bond concentration. The same applies to the inhibition period (the time up to the start of the polymerization). An estimation of the stability is possible with these two parameters.
A Theoretical Approach to Pressure Drop across Cyclone Separators
Authors: Zhao B. 
Published: October 2004

AbstractBased on investigation of the flow pattern in cyclone separators, a new theoretical model was developed for the prediction of pressure drop across cyclone separators. This model includes the effect of the geometrical dimensions and flow parameters, and assumes that the total pressure drop consists of four main partial pressure drops due to gas expansion at the separator entrance, wall friction within the separator, swirling motion of the gas, and gas flow through the outlet pipe. The availability of the method is verified by the comparison of calculated values with experimental data and with other models for different dimensions of cyclones.
Influence of Oxygen and Dissolved Inorganic Additives on the Removal of Gaseous Acetylaldehyde by Use of a Wetted‐Wall Corona Discharge Reactor
Authors: Faungnawakij K. , Sano N. , Yamamoto D. , Kanki T. , Charinpanitkul T. , Tanthapanichakoon W. 
Published: October 2004

AbstractA cylindrical wetted‐wall corona discharge reactor was used for the removal of acetaldehyde in gas mixtures of N2 and O2. Gaseous acetaldehyde was removed from the gas stream by simultaneous absorption and gaseous corona reaction. The acetaldehyde absorbed in water, was decomposed by the aqueous radical, OH, produced by contact of the gas corona with the water film. There is an optimized oxygen concentration for the effective removal. When oxygen coexists in the gas mixture at 5 %, acetaldehyde was effectively removed, resulting in overall sustainable removal of acetaldehyde. However, an increase in oxygen concentration resulted in a decrease in the extent of removal, when the corona current was excessively high. This is due to corona‐induced turbulence broadening the residence time distribution of gas in the reaction zone. The decompositions of absorbed acetaldehyde and TOC in water were obviously affected by the varied oxygen concentrations. Acetaldehyde was not removed in the absence of oxygen. The dissolved inorganic additives, NaOH and HCl, strongly affected the acetaldehyde absorbability into water and subsequently, the decomposition rate of the absorbed acetaldehyde.
Oxidation of CS2 by AsBr4+: The Unexpected Formation of the Simple CS2Br3+ Carbenium Ion
Authors: Gonsior Marcin , Krossing Ingo 
Published: October 2004

AbstractDuring the preparation of AsBr4+[Al(OR)4]−, the novel carbocation CS2Br3+ was synthesized by reaction of AsBr3, Br2, CS2, and Ag[Al(OR)4] (R=C(CF3)3). CS2Br3+[Al(OR)4]− was characterized by its crystal structure, NMR and IR spectroscopy, and quantum chemical calculations (including COSMO solvation enthalpies). Additional experiments as well as the computed thermodynamics indicated two likely reaction pathways: Ag++2 Br2+CS2→CS2Br3++AgBr and the direct 4 e− oxidation reaction AsBr4++CS2→CS2Br3++1/6As6Br6. Both reactions were observed experimentally and were calculated to be exergonic in solution by −226 and −56 kJ mol−1 respectively. As a result of charge delocalization the CS and CBr distances in the cation are shortened by 0.06 to 0.08 Å; the SBr distances are also slightly shortened indicating a delocalization of the charge also to the bromine atoms in the (S)Br moieties. Based on an analysis of the cation–anion contacts as well as quantum chemical MP2 calculations, a delocalization model as a planar 10 π electron system is discussed and the π molecular orbitals are given. It will be shown that the electronic situation of CS2Br3+ is very close to that in CBr3+, that is, the properties of SBr moieties and Br atoms as π donors towards a formal C+ center are comparable.
Electron Delocalization in Linearly π‐Conjugated Systems: A Concept for Quantitative Analysis
Authors: Giuffreda Maria Grazia , Bruschi Maurizio , Lüthi Hans Peter 
Published: October 2004

AbstractDonor‐ and/or acceptor‐substituted π‐conjugated systems represent an important class of compounds in organic chemistry. However, up to now, a general method to quantitatively address the efficiency of a conjugated path is still missing. In this work, a novel computational approach based on deletion energies and on second‐order orbital interaction energies in a natural bond orbital (NBO) scheme is employed to quantitatively assess (“measure”) delocalization energies. Moreover, the purpose of this work is to assess the efficiency of distinct π‐conjugated paths, that is, geminal, cis, and trans, as well as to predict the impact of substituents on a given backbone. This study is focused on various mono‐, di‐, tri‐, and tetrasubstituted tetraethynylethenes (TEEs). These model systems are suitable for our analysis, because they offer distinct conjugation paths within the same molecule, and can also be substituted in multiple ways. Differences between conjugation paths, the effect of neighbor paths, and the impact of donor and acceptor substituents on the various paths are discussed.
CC Double‐ and Triple‐Bond Formation from Reactions of B Atoms with CO: Experimental and Theoretical Characterization of OBBCCO and OBCCBO Molecules in Solid Argon
Authors: Zhou Mingfei , Jiang Ling , Xu Qiang 
Published: October 2004

AbstractReactions of boron atoms with CO molecules in solid argon form the following boron carbonyl species (which have been reported earlier): BCO, BBCO, OCBBCO, B(CO)2, and B4(CO)2. The OCBBCO molecule underwent a photochemical rearrangement where CO was activated to form the OBBCCO and OBCCBO molecules. The new molecules were identified on the basis of isotopic IR studies with 10B, 11B, 13C16O, 12C18O, and carbon dioxide mixtures in addition to comparison with quantum‐chemical calculations of isotopic frequencies. Theoretical analyses showed that the OBBCCO and OBCCBO molecules are linear with CC double and triple bonding, respectively, and lie at a much lower energy than the linear OCBBCO structure.
Two‐Component Dendritic Gel: Effect of Stereochemistry on the Supramolecular Chiral Assembly
Authors: Hirst Andrew R. , Smith David K. , Feiters Martin C. , Geurts Huub P. M. 
Published: October 2004

AbstractThe self‐assembly of diaminododecane solubilised by four different stereoisomeric dendritic peptides to form gel‐phase materials in toluene was investigated. The second generation dendritic peptides were based on D‐ and L‐lysine building blocks, and each contained three chiral centres. By designing dendritic peptides in which the configurations of the chiral centres were modified, and applying them as gelator units, the assembly of stereoisomers could be investigated. In all cases, the self‐assembly of gelator units resulted in macroscopic gelation. However, the degree of structuring was modulated by the stereoisomers employed, an effect which changed the morphology and macroscopic behavior of the self‐assembled state. Enantiomeric (L,L,L or D,D,D) gelator units formed fibrous molecular assemblies, whilst the racemic gel (50 % L,L,L : 50 % D,D,D) formed a flat structure with a “woven” appearance. Gelator units based on L,D,D or D,L,L dendritic peptides also formed fibrous assemblies, but small‐angle X‐ray scattering indicated significant morphological differences were caused by the switch in chirality. Furthermore, the macroscopic stability of the gel was diminished when these peptides were compared with their L,L,L or D,D,D analogues. In this paper it is clearly shown that individual stereocentres, on the molecular level, are directly related to the helicity within the fibre. It is argued that the chirality controls the pattern of hydrogen bonding within the assembly, and hence determines the extent of fibre formation and the macroscopic gel strength.
Injecting Electronic Excitation Energy into an Artificial Antenna System through an Ru2+ Complex
Authors: Bossart Olivia , De Cola Luisa , Welter Steve , Calzaferri Gion 
Published: October 2004

AbstractThe Ru2+ complex [Ru(bpy)2(bpy‐ph4‐Si(CH3)3)]2+ can be electrostatically bound to the negatively charged channel entrances of dye‐loaded zeolite L crystals where it acts as a functional stopcock molecule. Impressive electronic triplet–singlet excitation energy transfer from the Ru2+ complex to the acceptor dye oxazine 1 (Ox1) located inside the channels can be observed when the donor molecule is selectively excited. Time‐resolved luminescence experiments have been performed on the separate components and on the assembled donor–acceptor material. The luminescence lifetime of the Ru2+ complex attached to the zeolite is reduced by a factor of 30 when Ox1 acceptor molecules are present. The fluorescence decay of Ox1 incorporated in zeolite L is single exponential with a lifetime of 3 ns. The much longer lifetime in zeolite L than in solution is due to the fact, that the diethyl groups are sterically restricted when the dye is inside the host.
Quasi‐wavelet solution of diffusion problems
Authors: Jiashi Tang , Zhuyong Liu 
Published: October 2004

AbstractA new method, quasi‐wavelet method, is introduced for solving partial differential equations of diffusion which are important to chemical and mechanical engineering. A new scheme for the extension of boundary conditions is proposed. The quasi‐wavelet method is utilized to discretize the spatial derivatives, while the Runge–Kutta scheme is employed for the time advancing. The problems of particle diffusion in the electrochemistry reaction and temperature diffusion in plates are studied. Quasi‐wavelet solution of the former problem is compared with those of a finite difference method. Solution of the latter problem is calibrated by analytical solution. Numerical results indicate that the quasi‐wavelet approach is very robust and efficient for diffusion problems. Copyright © 2004 John Wiley & Sons, Ltd.
Formulations and analysis of the spectral volume method for the diffusion equation
Authors: Sun Yuzhi , Wang Z.J. 
Published: October 2004

AbstractThe spectral volume (SV) method is a newly developed high‐order finite volume method for hyperbolic conservation laws on unstructured grids. It has been successfully demonstrated for multi‐dimensional Euler equations. We wish to extend the SV method to the Navier–Stokes equations. As a first‐step towards achieving that goal, the SV method is extended to and tested for the diffusion equation. In this paper, we present three different formulations of the spectral volume method for the diffusion equation. The first formulation yields an inconsistent and unstable scheme, while the other two formulations are consistent, convergent and stable. A Fourier type analysis is performed for all the formulations, and the analysis agrees well with numerical results. Copyright © 2004 John Wiley & Sons, Ltd.
Curve linearization and discretization for meshing composite parametric surfaces
Authors: Laug P. , Borouchaki H. 
Published: October 2004

AbstractIn the context of composite parametric surface meshing using a direct or an indirect (via the meshing of parametric domains) method, the discretization of interface curves joining patches plays a central part. In the case of an indirect method, the discretization of interface curves must be taken back to parametric spaces. This is usually done using root finding techniques for generally non‐linear parametric functions. This paper presents a new linearization technique to determine the above correspondence. In addition, this linearization of interface curves makes it possible to obtain their discretization without explicitly computing the arc length. This method has been implemented in a surface mesh generator and an example from Fluid Mechanics is given to illustrate the pertinence of the proposed approach. Copyright © 2004 John Wiley & Sons, Ltd.
Reduction in radiated emission from multilayer PCBs by the layer structure shielding a power plane
Authors: Haga Satoru , Nakano Ken , Hashimoto Osamu 
Published: October 2004

AbstractStrong radiated emission is caused by the power and ground plane resonance in multilayer printed circuit boards. The emission cannot be completely reduced as far as parallel plate structure with open edges. Therefore, a novel printed board has been proposed, which has symmetrical ground‐power‐ground layer stack‐up with the peripheral edges of the two ground planes connected to shield the power plane. It has been experimentally verified that the emission can be reduced to a degree that no peak can be observed and that the power input to the signal trace is hardly transformed to the radiated power. Further, since no electronic components or interconnect area for reduction in the emission are needed in the printed board, the printed board provides extremely useful realization of future higher packaging density. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(2): 50–60, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10193