bluuebunny/crossref_metadata_2025_split huggingface dataset:
Promoting ecologic health resilience for minority youth: Enhancing health care access through the school health center
Authors: Clauss‐Ehlers Caroline C.C. 
Published: March 2003

AbstractEthnic minority youth experience problems in access to healthcare, yet little is known about how to enhance utilization. This article will discuss the demographic realities of children of color in the United States, with a focus on health care needs and access issues that have an enormous influence on health status. The article will consider health policy as it describes the considerable barriers to quality health care for minority youth such as a lack of a usual source of care and limited health insurance. An ecologic model is presented that incorporates cultural values and community structures into the school health center. Enhancing access and utilization through the school setting is viewed as promoting ecologic resilience in youth. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 265–278, 2003.
Professional preparation of pediatric school psychologists for school‐based health centers
Authors: Shaw Steven R. 
Published: March 2003

AbstractThe growth of school‐based health centers parallels the development of the subspecialty of pediatric school psychology. School psychologists have had minor roles in most school‐based health centers. In many cases, school psychologists with training in the foundation of school psychology do not have the specific skills to meet the role and function in a school‐based health center. However, there is a niche for the skills that can be provided by a school psychologist with subspecialty training in pediatric school psychology. A description of the potential roles for school psychologists in school‐based health centers is presented. The professional preparation beyond foundation school psychology training required to succeed in these roles is discussed. A detailed model for predoctoral internships and postdoctoral residencies for the professional preparation of pediatric school psychologists is presented. With this advanced level of training, school psychologists are well prepared to meet the expanded role and function required in school‐based health clinics. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 321–330, 2003.
Inelastic electron tunneling due to magnons and phonons of antiferromagnetic layered MnPSe3 semiconductors
Authors: Yamaguchi K. 
Published: March 2003

AbstractInelastic electron tunneling spectra of Pb/MnPSe3/Pb junctions are measured below liquid helium temperature in the normal state of lead under an external magnetic field. The insulating barrier of MnPSe3, an antiferromagnetic layered transition metal phosphorous triselenide, is cleaved from a single crystal along the layer. The spectra are explained by interactions between tunneling electrons and MnPSe3 antiferromagnetic magnons as well as those between tunneling electrons and MnPSe3 phonons. The contribution of MnPSe3 magnons to inelastic processes is comparable to that of MnPSe3 phonons.
Temperature dependence of the EPR spectrum of Co2+ ion in crystals Zn(BF4)2 × 6H2O
Authors: Neilo G. N. , Prokhorov A. A. , Lykin S. N. , Karnachev A. S. , Prokhorov A. D. 
Published: March 2003

AbstractThe study of EPR spectrum of the Co2+ ion replacing Zn2+ in crystals Zn (BF4)2 × 6H2O in a wide temperature area in the X and Q ranges is carried out. The temperature dependence of the line width is measured. The separated spin–phonon contribution to the line width allowed to determine the temperature dependence of the spin–lattice relaxation rate and to show that the main relaxation process is the Raman one. For the first time the temperature dependence of the g‐factor for an ion of the iron group is found out.
Transport characteristics of ferromagnetic single‐electron transistors
Authors: Weymann I. , Barnaś J. 
Published: March 2003

AbstractSpin‐dependent electronic transport in a single‐electron transistor with ferromagnetic external electrodes and ferromagnetic or nonmagnetic central part (island) is analyzed theoretically in the sequential tunneling regime. Nonequilibrium magnetic polarization of the island due to spin accumulation (spin‐dependent chemical potential) is taken into account. The accumulation takes place when the spin relaxation time on the island is sufficiently long. The crossover from slow to fast spin relaxation limits is also analyzed. The tunnel magnetoresistance, magnetic polarization of the island, and spin polarization of the flowing current are examined as a function of the bias and gate voltages.
Modeling of melting enthalpy of organic nanowires
Authors: Liang L. H. , Li J. C. , Jiang Q. 
Published: March 2003

AbstractA model is developed to interpret size‐dependent melting enthalpy of nanocrystals based on consideration of the effect of surface bond number and bond strength on cohesive energy of crystals and the corresponding liquids. The model prediction corresponds to the experimental results of organic nanowires well.
Electronic and magnetic properties of diluted magnetic semiconductors A1– xMnxTe (A = Cd, Zn) (0 ≤ x ≤ 1)
Authors: Hamedoun M. , Elachheb Zahia , Bakrim H. , Hourmatallah A. , Benzakour N. , Jorio A. , Hachimi M. 
Published: March 2003

AbstractWe have investigated the magnetic and electronic properties of diluted magnetic semiconductors (DMS) Cd1–xMnxTe and Zn1–xMnxTe. The magnetic phase diagrams have been determined by the replica method in the framework of the Ising model using the variational principle. The obtained results are in agreement with the experimental ones. A spin glass state has been obtained for x < xc (xc = 0.6). This phase is attributed to the randomness and the frustration of the antiferromagnetic interactions between the Mn magnetic ions arising from the topology of the DMS alloys. The sp3 semi‐empirical nearest‐neighbour tight‐binding formalism is used to compute the band structures of the above two systems in the hole range of concentration 0 ≤ x ≤ 1. The variation of the gap energy Eg with x is presented. The magnetic blueshift for x > xc is discussed in relation with the published magnetic results.
A nonparametric test for proving noninferiority in clinical trials with ordered categorical data
Authors: Munzel Ullrich , Hauschke Dieter 
Published: March 2003

AbstractWe consider the problem of proving noninferiority when the comparison is based on ordered categorical data. We apply a rank test based on the Wilcoxon–Mann–Whitney effect where the asymptotic variance is estimated consistently under the alternative and a small‐sample approximation is given. We give the associated 100(1−α)% confidence interval and propose a formula for sample size determination. Finally, we illustrate the procedure and possible choices of the noninferiority margin using data from a clinical trial. Copyright © 2003 John Wiley & Sons, Ltd.
Attaining optimal controls for manipulating quantum systems
Authors: Zhu Wusheng , Rabitz Herschel 
Published: March 2003

AbstractThis article reviews the procedures for attaining laser optimal control fields to manipulate the dynamics of quantum systems. Optimal control theory, whether implemented as a computational technique or directly in the laboratory, is the most general means to achieve precise control of quantum systems. In the case of theoretical control design, a class of monotonically convergent iteration algorithms are presented, which can reduce the computational effort involved. Implementation of optimal control field design can provide physical insight into the feasibility and mechanism of control, even for quantum systems whose Hamiltonian might contain some degree of uncertainty. Moreover, optimal quantum control fields may be directly determined in the laboratory by an analogous procedure with the molecule subject to manipulation acting as an analog computer to guide the discovery of successful controls. To facilitate this process closed‐loop iteration is set up with the loop consisting of the laser, the molecular sample, and a learning algorithm to recognize patterns in the control fields giving rise to successful experimental outcomes. Theoretical design and laboratory learning can act in tandem with each other to achieve the best control and reveal information on how the control process occurs. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Generation of finite element meshes on molecular surfaces
Authors: Laug P. , Borouchaki H. 
Published: March 2003

AbstractAn increasingly important part of quantum chemistry involves molecular surfaces. To model such a surface, the basic idea is to assimilate each constituting atom with a simple sphere. Surface mesh generation techniques can then be used for visualization but also for simulation, where mesh quality has a strong influence on solution accuracy. This article presents a new approach to generating quality meshes on arbitrary molecular surfaces (van der Waals, solvent‐accessible, or solvent‐excluded surfaces). First, a boundary representation (B‐rep) of the surface is obtained, i.e., a set of patches and the topological relations between them. Second, an appropriate parameterization is computed for each kind of patch and the user‐specified element sizes are converted into an isotropic metric map. Third, meshes of the parametric domains are generated with respect to an induced anisotropic metric map, using a combined advancing‐front–generalized Delaunay approach. Finally, these meshes are mapped onto the entire surface. The proposed method has been integrated within the BLMOL mesh generator and application examples are given to illustrate its capabilities. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Orthogonal polynomials of a discrete variable as expansion basis sets in quantum mechanics: Hyperquantization algorithm
Authors: De Fazio Dario , Cavalli Simonetta , Aquilanti Vincenzo 
Published: March 2003

AbstractIn recent years, orthogonal polynomials of a discrete variable have been widely investigated both as tools of numerical analysis for the representation of functions on grids and as the superposition coefficients that appear as matrix elements of the overlap between spherical and hyperspherical harmonics corresponding to alternative coordinate systems. This article reviews our work concerning the extension of their use to quantum mechanical problems. By exploiting both their connection with coupling and recoupling coefficients of angular momentum theory and their asymptotic relationships (semiclassic limit) with spherical and hyperspherical harmonics, a discretization procedure, the hyperquantization algorithm, has been developed and applied to the study of anisotropic interactions and of reactive scattering as a quantum mechanical n‐body problem. One of the most appealing features of this method has turned out to be a drastic reduction of memory requirements and computing time for extensive dynamic calculations as obtained by a diagonal matrix formulation of the interparticle interaction (the stereodirected representation). Use for fitting of potential energy surfaces has been also proposed and further applications have been made to stereodirected dynamics via an exact representation for the scattering matrix as well as to the characterization of molecular beam polarization. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Application of single‐particle laser desorption/ionization time‐of‐flight mass spectrometry for detection of polycyclic aromatic hydrocarbons from soot particles originating from an industrial combustion process
Authors: Zimmermann R. , Ferge T. , Gälli M. , Karlsson R. 
Published: March 2003

AbstractCombustion‐related soot particles were sampled in situ from the stoker system of a 0.5 MW incineration pilot plant (feeding material was wood) at two different heights over the feed bed in the third air supply zone. The collected particles were re‐aerosolized by a powder‐dispersing unit and analyzed by a single‐particle laser desorption/ionization (LDI) time‐of‐flight mass spectrometer (aerosol‐time‐of‐flight mass spectrometry, ATOFMS). The ATOFMS instrument characterizes particles according to their aerodynamic size (laser velocimetry) and chemical composition (LDI mass spectrometry). Chemical species from the particles are laser desorbed/ionized by 266 nm Nd:YAG laser pulses. ATOFMS results on individual ‘real world’ particles in general give information on the bulk inorganic composition. Organic compounds, which are of much lower concentrations, commonly are not detectable. However, recent off‐line laser microprobe mass spectrometric (LMMS) experiments on bulk soot aerosol samples have emphasized that organic compounds can be desorbed and ionized without fragmentation in LDI experiments from black carbonaceous matrices. This paper reports the successful transfer of the off‐line results to on‐line analysis of airborne soot particles by ATOFMS. The detection of polycyclic aromatic hydrocarbons from soot particles is addressed in detail. The results are interpreted in the context of the recent LMMS results. Furthermore, their relevance with respect to possible applications in on‐line monitoring of combustion processes is discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Rapid determination of orotic acid in urine by a fast liquid chromatography/tandem mass spectrometric method
Authors: Marca Giancarlo la , Casetta Bruno , Zammarchi Enrico 
Published: March 2003

AbstractQuantification of orotic acid (uracil‐6‐carboxylic acid) in urine is an important tool to diagnose some inherited diseases, such as urea cycle disorder (OTCD) and hereditary orotic aciduria. New rapid analytical methods are necessary to provide high‐throughput orotic acid analyses. A new analytical method has been developed for the rapid analysis of orotic acid in urine by liquid chromatography coupled with ion spray tandem mass spectrometry (LC/MS/MS). After a sample dilution 1:20, the analysis was performed in the selected reaction monitoring mode in which orotic acid was detected through the transition m/z 155 to 111. The retention time was 3.9 min in a 4.5‐min analysis. Daily calibration between 0.5–5.0 μmol/L of orotic acid, corresponding to 10–100 μmol/L in urine before the 1:20 dilution, offered consistent linearity and reproducibility. Interassay coefficient of variance (c.v.) was 4.97% at a mean concentration of 10.99 μmol/L. The sensitivity and specificity of tandem mass spectrometry permitted a high volume of analyses of orotic acid. The sample preparation is simple, inexpensive and not time demanding. Copyright © 2003 John Wiley & Sons, Ltd.
Chemical ionization of substituted naphthalenes using tetrahydrofuran as a reagent in gas chromatography with ion trap mass spectrometry
Authors: Tzing Shin‐Hwa , Ghule Anil , Chang Jia‐Yaw , Ling Yong‐Chien 
Published: March 2003

AbstractThe ion/molecule reactions of nine monosubstituted naphthalene compounds in chemical ionization mass spectrometry (CI‐MS) were studied using tetrahydrofuran (THF) as CI reagent. Proton affinity factors, substituent effects and the preferred site of adduct ion attachment were examined. Good correlation was observed between proton affinity and the formation of [M]+. and [M+H]+ ions. The influence of substituents on protonation and site‐specific adduct [M+13]+ and [M+41]+ ion formation is also observed, with the cyano substituent showing the most stable [M+41]+ ion. Collision‐activated dissociation experiments were used to characterize the variety of adducts formed under CI conditions, and provided insight into product ion structures and mechanisms of dissociation and condensation during CI‐MS/MS. Copyright © 2003 John Wiley & Sons, Ltd.
Quantification of acetaldehyde released by lung cancer cells in vitro using selected ion flow tube mass spectrometry
Authors: Smith David , Wang Tianshu , Sulé‐Suso Josep , Španěl Patrik , Haj Alicia El 
Published: March 2003

AbstractThe production of volatile compounds from cancer cell lines in vitro has been investigated using selected ion flow tube mass spectrometry (SIFT‐MS). This technique enables on‐line quantitative analyses of the headspace above cell/medium cultures. This paper reports the discovery that acetaldehyde is released by the lung cancer cell lines SK‐MES and CALU‐1. The concentration of acetaldehyde in the headspace of the medium/cell culture was measured after 16 h incubation at 37°C and found to be proportional to the number of cancer cells in the medium (typically 108). From these data, the acetaldehyde production rates of the SK‐MES cells and the CALU‐1 cells in vitro are determined to be 1 × 106 and 1.5–3 × 106 molecules/cell/min, respectively. The potential value of this new technique in cell biology and in industrial cell biotechnology is discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Comparison of conventional and enhanced mass resolution triple‐quadrupole mass spectrometers for discovery bioanalytical applications
Authors: Xu Xiaoying , Veals John , Korfmacher Walter A. 
Published: March 2003

AbstractA new triple‐quadrupole mass spectrometry (MS) system with enhanced resolution capabilities has recently become available. In order to evaluate the performance of this new instrument for drug discovery assays, both the linearity and the limit of detection were compared in the positive electrospray ionization (ESI) mode with those of a conventional triple‐quadrupole instrument supplied by the same manufacturer. For these studies, spiked mouse plasma standard samples were split and assayed by each instrument, which allowed for a direct comparison of the two systems. In the unit mass resolution mode, the new mass spectrometer was found to be at least ten‐fold more sensitive than the conventional instrument. The sensitivity of the new mass spectrometer under the enhanced mass resolution mode was found to be even better by another factor of two. For the test compound, the linear dynamic range was found to be 0.05–5000 ng/mL for the new instrument as compared with 2.5–5000 ng/mL for the conventional mass spectrometer. Copyright © 2003 John Wiley & Sons, Ltd.
Theory of relative sputtering rates in GDOES
Authors: Payling Richard , Aeberhard Max , Michler Johann , Authier Cyril , Chapon Patrick , Nelis Thomas , Pitchford Leanne 
Published: March 2003

AbstractA detailed theory of relative sputtering rates for glow discharge optical emission spectroscopy (GDOES) is presented for the first time. The theory suggests that such sputtering rates should be nearly independent of plasma conditions. This is supported by experimental results for r.f. GDOES under varying applied power or varying pressure. Relative sputtering rates are calculated for a range of cast irons, high‐alloy steels and zinc–aluminium alloys. Within measurement uncertainties, the calculated rates agree with measured relative sputtering rates. Copyright © 2003 John Wiley & Sons, Ltd.
XPS study of carboxylic acid layers on oxidized metals with reference to particulate materials
Authors: Johansson Elisabeth , Nyborg Lars 
Published: March 2003

AbstractLow‐molecular‐weight organic additives such as stearic acid are commonly used as surface additives in powder injection moulding (PIM). It is therefore important to know how the additives interact with the surface of the powder used. In this study, such interactions are studied by means of controlled adsorption of carboxylic acids on the oxides of interest. The oxides are prepared by oxidation of flat samples of Fe, Cr, Mn and Si. Surface chemical characterization is done by means of XPS, the main approach on flat samples being a comparison of angle‐resolved analysis and the use of the Tougaard nanostructure analysis technique. Taking advantage of this comparison, the Tougaard method is then applied in the evaluation of XPS analyses of stainless‐steel powder with adsorbed stearic acid. In addition, time‐of‐flight SIMS analysis is used to verify the adsorption of stearic acid on the powder surface.It is shown that Tougaard nanostructure analysis can be used for determining the thickness of an organic layer on particulate material. The layer thickness of adsorbed stearic acid was estimated to be ∼20 Å, corresponding to monolayer adsorption. Time‐of‐flight SIMS analysis verified the adsorption of stearic acid on the powder surface. From the XPS analysis of flat samples it was determined that the use of the metal/oxide universal cross‐section in Tougaard nanostructure analysis best described the increased background due to adsorption of carboxylic acids, and that information about molecular orientation could be gained. Copyright © 2003 John Wiley & Sons, Ltd.
SAXS study of polymer adsorption on porous ZrO2
Authors: Pikus Stanislaw , Chibowski Stanislaw , Olszewska Elżbieta , Wiśniewska Malgorzata 
Published: March 2003

AbstractThe small‐angle X‐ray scattering method (SAXS) has been used for the analysis of polymer adsorption on porous ZrO2. Particular attention has been paid to the adsorption of polyacrylic acid (PAA) and polyacrylamide (PAM) on the surface of porous ZrO2. It has been established that the SAXS method determines whether the polymer has penetrated the carrier's pores, and that polymers of low molecular weight create a thin transition layer on the surface of ZrO2 (understood in the context of a change in the electron density). The creation of this layer is clearly reflected in the run of SAXS curves (Porod's plot). Ruland–Vonk's method has been used to determine the thickness of the transition layer. The results are consistent with those obtained when the viscosity method was used. Copyright © 2003 John Wiley & Sons, Ltd.
Obtaining quantitative information on surface excitations from reflection electron energy‐loss spectroscopy (REELS)
Authors: Werner Wolfgang S. M. 
Published: March 2003

AbstractA new analysis of reflection electron energy‐loss spectroscopy (REELS) spectra is presented. Assuming inelastic scattering in the bulk to be quantitatively understood, this method provides the distribution of energy losses in a single surface excitation in absolute units without the use of any fitting parameters. For this purpose, REELS spectra are decomposed into contributions corresponding to surface and volume excitations in two steps: first the contribution of multiple volume excitations is eliminated from the spectra and subsequently the distribution of energy losses in a single surface scattering event is retrieved. This decomposition is possible if surface and bulk excitations are uncorrelated, a condition that is fulfilled for medium‐energy electrons because the thickness of the surface scattering layer is small compared with the electron elastic mean free path. The developed method is successfully applied to REELS spectra of several materials. The resulting distributions of energy losses in an individual surface excitation are in good agreement with theory. In particular, the so‐called begrenzungs effect, i.e. the reduction of the intensity of bulk losses due to coupling with surface excitations near the boundary of a solid‐state plasma, becomes clearly observable in this way. Copyright © 2003 John Wiley & Sons, Ltd.