bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the Peano–Gosper fractile array and the regular hexagonal array
Authors: Bogard J. N. , Werner D. H. , Werner P. L. 
Published: October 2004

AbstractA new class of modular broadband low‐sidelobe arrays, based on the theory of fractile (fractal tile) geometry, has been recently introduced. In this paper, the radiation properties of the Peano–Gosper fractile array are compared to those of the conventional square and hexagonal arrays. It is demonstrated that the Peano–Gosper array has the same desirable grating‐lobe conditions as the hexagonal array, while achieving a much lower overall sidelobe level. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 524–526, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20523
Mouse Xist expression begins at zygotic genome activation and is timed by a zygotic clock
Authors: Zuccotti Maurizio , Boiani Michele , Ponce Ruben , Guizzardi Stefano , Scandroglio Renato , Garagna Silvia , Redi Carlo Alberto 
Published: October 2004

AbstractThe imprinted mouse Xist (X‐inactive specific transcript) gene is involved in the initiation of X‐chromosome inactivation. Only the paternal Xist is expressed in preimplantation development beginning from the 4‐cell stage, preceding and in correlation with paternal X‐inactivation in the extraembryonic lineage of the blastocyst. To better understand the mechanisms regulating Xist expression in early development, we investigated the precise timing of its onset. We set up a single‐cell RT‐PCR for the simultaneous analysis on single embryos of Xist and Hprt (internal control) cDNAs and a Y‐chromosome specific DNA sequence, Zfy (for embryo sexing). Applying this procedure, we demonstrate that Xist expression begins at the G2‐phase of 2‐cell female embryos, earlier than previously reported and at the same time of the major wave of zygotic genome activation (ZGA). We then examined, if Xist expression at the 2‐cell stage is dependent on the lapse of time spent since fertilization, as previously reported for zygotic genes. One‐cell embryos at the G2‐phase of the first cell‐cycle were cultured with cytochalasin D (inhibitor of cytokinesis but not of DNA synthesis or nuclear progression) for a time equivalent to the 4‐cell stage in control, untreated embryos. We show that Xist activation occurs at a scheduled time following fertilization despite the embryos being blocked at the 1‐cell stage, suggesting the existence of a zygotic clock involved in the regulation of the transcription of this imprinted gene. Mol. Reprod. Dev. 61: 14–20, 2002. © 2002 Wiley‐Liss, Inc.
Nerve conduction changes in patients with mitochondrial diseases treated with dichloroacetate
Authors: Spruijt Liesbeth , Naviaux Robert K. , McGowan Karen A. , Nyhan William L. , Sheean Geoffrey , Haas Richard H. , Barshop Bruce A. 
Published: October 2004

AbstractSerial measurements of nerve conduction velocities and amplitudes were performed in 27 patients with congenital lactic acidemia over 1 year of sodium dichloroacetate (DCA) administration. Patients were treated with oral thiamine (100 mg) and DCA (initial dose of 50 mg/kg) daily. Nerve conduction velocity and response amplitude were measured in the median, radial, tibial, and sural nerves at 0, 3, 6, and 12 months, and plasma DCA pharmacokinetics were measured at 3 and 12 months. Baseline electrophysiologic parameters in this population were generally below normal but as a group were within 2 standard deviations of normal means. Although symptoms of neuropathy were reported by only three patients or their families, nerve conduction declined in 12 patients with normal baseline studies, and worsening of nerve conduction occurred in the two who had abnormalities at baseline. Peripheral neuropathy appears to be a common side effect during chronic DCA treatment, even with coadministration of oral thiamine. Nerve conduction should be monitored during DCA treatment. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 916–924, 2001
A new importance sampling Monte Carlo method for a flow network reliability problem
Authors: Bulteau Stéphane , El Khadiri Mohamed 
Published: October 2004

AbstractThe exact evaluation of the probability that the maximum st‐flow is greater than or equal to a fixed demand in a stochastic flow network is an NP‐hard problem. This limitation leads one to consider Monte Carlo alternatives. In this paper, we propose a new importance sampling Monte Carlo method. It is based on a recursive use of the state space decomposition methodology of Doulliez and Jamoulle during the simulation process. We show theoretically that the resulting estimator belongs to the variance‐reduction family and we give an upper bound on its variance. As shown by experimental tests, the new sampling principle offers, in many cases, substantial speedups with respect to a previous importance sampling based on the same decomposition procedure and its best performances are obtained when highly reliable networks are analyzed. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 204–228, 2002; DOI 10.1002/nav.10004
A network based model of a promotion‐sensitive grocery logistics system
Authors: Iyer Ananth V. , Ye Jianming 
Published: October 2004

AbstractWe use a network model to choose retail prices in a grocery logistics system consisting of a warehouse (managed by a manufacturer) that supplies stores (managed by a retailer). We model retail prices as endogenous decisions that respond to store‐level cost and demand parameters. The retail prices are chosen to maximize the retailer's expected profits. The retail environment is captured by a three‐segment retail customer model where segments differ in their reservation price, size, and propensity to stockpile. The resulting network model chooses retail prices each period to optimize profits across the horizon. Retail price variation across time is profit‐maximizing because of the promotion sensitivity of the retail environment. We also model the impact of retail price variation on the manufacturer costs, warehouse inventory levels, and associated manufacturer expected profit. The suggested model is fit to a dataset consisting of retail prices and associated sales of canned soup. The model parameters as well as the residual variance are included in the decision model that generates the optimal retail prices that maximize the expected retail profit. We use model runs from the empirical dataset to show that (i) retail price variation can be profit‐maximizing for the retailer, (ii) retail market‐share constraints can decrease both manufacturer and retailer profits, and (iii) manufacturer price variation can be beneficial for the manufacturer and the retailer. The results show that manufacturer and retailer price variation can play a valuable role in improving logistics system performance in promotional retail environments. © 2001 John Wiley & Sons, Inc.
Neuroprotective signal transduction in model motor neurons exposed to thrombin: G‐protein modulation effects on neurite outgrowth, Ca2+ mobilization, and apoptosis
Authors: Smirnova Irina V. , Citron Bruce A. , Arnold Paul M. , Festoff Barry W. 
Published: October 2004

AbstractThrombin, the ultimate protease in the blood coagulation cascade, mediates its known cellular effects by unique proteolytic activation of G‐protein‐coupled protease‐activated receptors (PARs), such as PAR1, PAR3, and PAR4, and a “tethered ligand” mechanism. PAR1 is variably expressed in subpopulations of neurons and largely determines thrombin's effects on morphology, calcium mobilization, and caspase‐mediated apoptosis. In spinal cord motoneurons, PAR1 expression correlates with transient thrombin‐mediated [Ca2+]i flux, receptor cleavage, and elevation of rest [Ca2+]i activating intracellular proteases. At nanomolar concentrations, thrombin retracts neurites via PAR1 activation of the monomeric, 21 kDa Ras G‐protein RhoA, which is also involved in neuroprotection at lower thrombin concentrations. Such results suggest potential downstream targets for thrombin's injurious effects. Consequently, we employed several G‐protein‐specific modulators prior to thrombin exposure in an attempt to uncouple both heterotrimeric and monomeric G‐proteins from motoneuronal PAR1. Cholera toxin, stimulating Gs, and lovastatin, which blocks isoprenylation of Rho, reduced thrombin‐induced calcium mobilization. In contrast, pertussis toxin and mastoparan, inhibiting or stimulating Go/Gi, were found to exacerbate thrombin action. Effects on neuronal rounding and apoptosis were also detected, suggesting therapeutic utility may result from interference with downstream components of thrombin signaling pathways in human motor neuron disorders, and possibly other neurodegenerative diseases. Published 2001 John Wiley & Sons, Inc. J Neurobiol 48: 87–100, 2001
An interval finite element approach for the calculation of envelope frequency response functions
Authors: Moens David , Vandepitte Dirk 
Published: October 2004

AbstractThis paper focusses on the application of the interval finite element method in dynamic analyses. It describes a methodology for calculating frequency response function envelopes from a finite element model containing imprecise parameters defined as interval uncertainties. The resulting envelope functions give a conservative approximation of the possible range of the frequency response function, taking into account that the uncertain parameters in the model can adopt any value in their presumed uncertainty intervals. The methodology is based on the modal superposition principle. It consists of an interval aritmethic algorithm which processes the results of a preliminary global optimization performed on the modal parameters. The algorithm is constructed such that it optimally combines the advantages of both the anti‐optimization and the interval arithmetic strategy for general numerical interval calculations.In the first stage of the development, the modal parameter ranges of each individual mode are independently combined in the modal response contributions. This yields the modal rectangle (MR) method. In order to remedy the high conservatism inherent to the MR method, the exact eigenfrequency ranges are added to the analysis. This results in the modal rectangle method with eigenfrequency interval correction (MRE). A second improvement consists of adding extra delimiters to the MRE modal parameter range approximation. This is achieved by performing an extra optimization on the modal response contributions at discrete frequencies. The method is referred to as the locally optimized modal rectangle method with eigenfrequency interval correction (OMRE). Finally, a numerical example illustrates the different algorithms. Copyright © 2004 John Wiley & Sons, Ltd.
First‐trimester combined ultrasound and biochemical screening for Down syndrome in routine clinical practice
Authors: Stenhouse E. J. , Crossley J. A. , Aitken D. A. , Brogan K. , Cameron A. D. , Connor J. M. 
Published: October 2004

AbstractObjectivesTo assess the effectiveness of combined ultrasound and biochemical (CUB) screening for chromosome abnormalities in singleton pregnancies in a routine antenatal clinic and laboratory setting.MethodsWomen whose pregnancies fell within the gestational age range of 11 to 14 weeks by ultrasound assessment were offered CUB screening on the basis of measurement of nuchal translucency (NT), maternal serum free beta‐human chorionic gonadotrophin (FβhCG) and pregnancy‐associated plasma protein A (PAPP‐A). NT measurements were obtained using a standardised method defined by the Fetal Medicine Foundation and FβhCG, and PAPP‐A were measured using the DELFIA immunoassay system. Each screening marker measurement was converted to a multiple of the appropriate gestational median and a risk was derived using previously published parameters for each marker in chromosomally abnormal and unaffected pregnancies. A combined risk of Down syndrome and of trisomy 18/13, incorporating the maternal age risk, was calculated for all women. Invasive diagnostic testing was offered to women whose combined risk exceeded the cut‐off risk of 1 in 250 (term).ResultsFive thousand and eighty‐four women accepted a first‐trimester screening test for Down syndrome, representing 75% of the eligible booking population. Out of the population eligible for CUB screening at the time of booking, NT measurements were obtained from 93% at the first clinic visit and 7% had to return for a second attempt. After excluding women who defaulted on a return visit, satisfactory NT measurements were obtained in 99.5% of pregnancies. Fifteen cases of Down syndrome and eleven pregnancies with other chromosome abnormalities were ascertained. The detection rate for Down syndrome was 93% (14/15) at a false‐positive rate of 5.9% and for all chromosome abnormalities it was 96% (25/26) at an overall false‐positive rate of 6.3%.ConclusionsCUB screening offers a significant improvement in sensitivity over second‐trimester biochemical screening and is deliverable within a routine prenatal clinical setting. Copyright © 2004 John Wiley & Sons, Ltd.
Changing indications for fetal echocardiography in a University Center population
Authors: Friedberg Mark K. , Silverman Norman H. 
Published: October 2004

AbstractObjectivesWe hypothesized that increased facility with fetal echocardiographic diagnosis by obstetricians is associated with changes in its indications and yields.MethodsWe reviewed 300 fetal echocardiograms (December 2002–August 2003) and compared our findings with previous studies.ResultsMean maternal age was 31 ± 6 (range 16–44) years. Gestational age was 24 ± 5 weeks (mean ± SD; median 22, range 15–38). Indications for fetal echocardiography included family history of congenital heart disease (CHD) (23%), maternal diabetes (18%), obstetrical scan suspicious for CHD (13%), arrhythmia (12%) maternal rheumatologic disease (7%), extracardiac congenital anomalies (6%), chromosomal anomaly (6%) and exposure to a potential fetal teratogen (5%). High yield indications included chromosomal anomaly (47%) and a suspicious obstetrical scan (42%). Low yield indications included family history of CHD (4%) and teratogen exposure (0%). 1/7 of the patients with increased nuchal translucency had pulmonary atresia/intact ventricular septum. No anomalies were associated with the single umbilical artery.ConclusionIndications and yields of fetal echocardiography have changed over the last decade. The frequency of an obstetrical scan suspicious for CHD has increased 2.5 to 3 times over a decade and continues to have high yield. Thus, increasing prenatal detection of CHD depends, to a large extent, on increasing the skills of obstetricians. Copyright © 2004 John Wiley & Sons, Ltd.
Body dissatisfaction, drive for thinness, and self‐esteem in African American college females
Authors: James Kimberly A. , Phelps LeAdelle , Bross Andrea L. 
Published: October 2004

AbstractNinety‐five African American undergraduate females who were attending three predominately Caucasian universities were evaluated for body dissatisfaction and drive for thinness as well as on four dimensions of self‐concept (physical, social, academic, and personal competence). The participants were largely middle class, with 78% reporting parental education levels between high school to college graduation. Results indicated body dissatisfaction and drive for thinness at levels commensurate with Caucasian samples. A hierarchial multiple regression found a combination of physical self‐concept, drive for thinness, and personal competence to be highly predictive of body dissatisfaction in this sample. Using this model, an effective psychosocial prevention program that focused on reduction of risk factors (e.g., drive for thinness) and enhancement of protective factors (e.g., satisfaction with physical appearance and abilities, personal efficacy) would be advantageous. It is suggested that prevention programming with African American women occur within a cultural context that may provide further support. That is, it may be beneficial to facilitate a critical evaluation of current social mores, encourage personal value clarification, and enhance individual resilience within a context of cultural pride. © 2001 John Wiley & Sons, Inc.
Middle childhood, poverty, and adjustment: Does social support have an impact?
Authors: Guest Kristi Carter , Biasini Fred J. 
Published: October 2004

AbstractThe present study evaluated 64 children and their primary caregivers who were living in poverty. The children were administered a stress measure, a social support measure, and a measure of self‐esteem. Caregivers completed a stress measure, a measure of child adjustment, and a demographic questionnaire. Social support was not found to moderate the relationship between stress and child outcome. However, social support was found to be one possible mediator of the child's reported stress on their self‐esteem. According to the mediating model, enhancing children's social support may positively influence their self‐esteem. Greater levels of self‐esteem can affect many aspects of children's lives, such as improving school performance and efforts toward achieving goals. Because of the important role that social support can play on children's self‐esteem, social support should be actively promoted through school and community groups and organizations, especially with children from disadvantaged economic situations. © 2001 John Wiley & Sons, Inc.
Search for highly resolved electron spin resonance spectra of the transient radical in radical polymerization
Authors: Kamachi Mikiharu 
Published: October 2004

AbstractThe detection of highly resolved spectra in electron spin resonance (ESR) measurements of radical polymerization is presented. Well‐resolved ESR spectra of the propagating radical were detected in the radical polymerization of several vinyl monomers with a specially designed cavity and cell. More highly resolved ESR spectra of the propagating radicals of vinyl and diene compounds were observed with aconventional spectrometer without the specially designed cavity and cell. On the basis of the ESR spectra, propagation rate constants and dynamic behavior of propagating radicals are discussed. Moreover, the application of time‐resolved ESR spectroscopy to research on the initiation process in radical polymerization is shown. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 269–285, 2002
Laser‐induced decomposition of 2,2‐dimethoxy‐2‐phenylacetophenone and benzoin in methyl methacrylate homopolymerization studied via matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Barner‐Kowollik Christopher , Vana Philipp , Davis Thomas P. 
Published: October 2004

AbstractPulsed laser polymerization (PLP) experiments were performed on the bulk polymerization of methyl methacrylate (MMA) at −34 °C. The aim of this study was to investigate the polymer end groups formed during the photoinitiation process of MMA monomer using 2,2‐dimethoxy‐2‐phenylacetophenone (DMPA) and benzoin as initiators via matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry. Analysis of the MALDI‐TOF spectra indicated that the two radical fragments generated upon pulsed laser irradiation show markedly different reactivity toward MMA: whereas the benzoyl fragment—common to both DMPA and benzoin—clearly participates in the initiation process, the acetal and benzyl alcohol fragments cannot be identified as end groups in the polymer. The complexity of the MALDI‐TOF spectrum strongly increased with increasing laser intensity, this effect being more pronounced in the case of benzoin. This indicates that a cleaner initiation process is at work when DMPA is used as the photoinitiator. In addition, the MALDI‐TOF spectra were analyzed to extract the propagation‐rate coefficient, kp, of MMA at −34 °C. The obtained value of kp = 43.8 L mol−1 s−1 agrees well with corresponding numbers obtained via size exclusion chromatography (kp = 40.5 L mol−1 s−1). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 675–681, 2002; DOI 10.1002/pola.10150
Surface modification of polystyrene latex particles via atom transfer radical polymerization
Authors: Min Ke , Hu Jianhua , Wang Changchun , Elaissari Abdelhamid 
Published: October 2004

AbstractThe atom transfer radical polymerization (ATRP) technique using the copper halide/ N,N′,N′,N″,N″‐pentamethyldiethylenetriamine complex was applied to the graft polymerization of methyl methacrylate and methyl acrylate on the uniform polystyrene (PS) seed particles and formed novel core‐shell particles. The core was submicron crosslinked PS particles that were prepared via emulsifier‐free emulsion polymerization. The crosslinked PS particles obtained were transferred into the organic phase (tetrahydrofuran), and surface modification using the chloromethylation method was performed. Then, the modified seed PS particles were used to initiate ATRP to prepare a controlled poly(methyl methacrylate) (PMMA) and poly(methyl acrylate) (PMA) shell. The final core‐shell particles were characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, thermogravimetric analysis, and elementary analysis. The grafting polymerization was conducted successfully on the surface of modified crosslinked PS particles, and the shell thickness and weight ratio (PMMA and PMA) of the particles were calculated. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 892–900, 2002; DOI 10.1002/pola.10160
Synthesis and thermal properties of hybrid copolymers of syndiotactic polystyrene and polyhedral oligomeric silsesquioxane
Authors: Zheng Lei , Kasi Rajeswari M. , Farris Richard J. , Coughlin E. Bryan 
Published: October 2004

AbstractCopolymerizations of styrene and the polyhedral oligomeric silsesquioxane (POSS)–styryl macromonomer 1‐(4‐vinylphenyl)‐3,5,7,9,11,13,15‐heptacyclopentylpentacyclo [9.5.1.13,9.15,15.17,13] octasiloxane have been performed with CpTiCl3 in conjunction with methylaluminoxane. Random copolymers of syndiotactic polystyrene (sPS) and POSS have been formed and fully characterized with 1H and 13C NMR, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. NMR data reveal a moderately high syndiotacticity of the polystyrene backbone consistent with this use of CpTiCl3 as a catalyst and POSS loadings as high as 24 wt % and 3.2 mol %. Thermogravimetric analysis of the sPS–POSS copolymers under both nitrogen and air shows improved thermal stability with higher degradation temperatures and char yields, demonstrating that the inclusion of the inorganic POSS nanoparticles makes the organic polymer matrix more thermally robust. The polymerization activity and thermal stability are also compared with those of reported atactic polystyrene–POSS copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 885–891, 2002; DOI 10.1002/pola.10175