bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trophectoderm‐specific expression of the X‐linked Bex1/Rex3 gene in preimplantation stage mouse embryos*
Authors: Williams Jean W. , Hawes Susan M. , Patel Bela , Latham Keith E. 
Published: August 2002

AbstractThe Bex1/Rex3 gene was recently identified as an X‐linked gene that is differentially expressed between parthenogenetic and normal fertilized, preimplantation stage mouse embryos. The Bex1/Rex3 gene appears to be expressed preferentially from the maternal X chromosome in blastocysts, but from either X chromosome in later stage embryonic tissues and adult tissues. To investigate whether differential expression of the Bex1/Rex3 gene between normal and parthenogenetic blastocyst stage embryos reflects genomic imprinting at the Bex1/Rex3 locus itself, or instead is the result of preferential inactivation of the paternal X chromosome or differences in timing of cellular differentiation, we examined in detail the expression pattern of the Bex1/Rex3 mRNA in normal preimplantation stage embryos, and compared its expression between androgenetic, gynogenetic, and normal fertilized embryos. Expression data reveal that the Bex1/Rex3 gene is initially transcribed at the 2‐cell stage, transiently induced at the 8‐cell stage, and then increases in expression again at the blastocyst stage. Very little expression is observed in isolated inner cell masses, indicating selective expression in the trophectoderm. Comparisons of Bex1/Rex3 mRNA expression between male and female androgenetic and control embryos and gynogenetic embros failed to reveal any significant difference in expression between the different classes of embryos at the 8‐cell stage, or the expanding blastocyst stage (121 hr post‐hCG). At the late blastocyst stage (141 hr post‐hCG), expression was significantly lower in XY control embryos as compared with XX controls. Bex1/Rex3 mRNA expression did not differ between XX and XY androgenones at the blastocyst stage or between gynogenones and XX control embryos. Thus, the Bex1/Rex3 gene does not appear to be regulated directly by genomic imprinting during the preimplantation period, just as it is not regulated by imprinting at later stages. Apparent differences in gene expression may arise through the effects of trophectoderm‐specific expression coupled with differences in timing of trophectoderm differentiation between the different classes of embryos and effects of preferential paternal X chromosome inactivation (XCI). Mol. Reprod. Dev. 61: 281–287, 2002. © 2002 Wiley‐Liss, Inc.
Cellular and molecular mechanisms mediating the effects of polychlorinated biphenyls on oocyte developmental competence in cattle
Authors: Pocar Paola , Brevini Tiziana A.L. , Perazzoli Federica , Cillo Fabiana , Modina Silvia , Gandolfi Fulvio 
Published: August 2002

AbstractPolychlorinated biphenyls (PCBs) can interfere with normal reproductive functions acting as endocrine disruptors. Aroclor‐1254 (A‐1254), is a pool of more than 60 congeners used for in vitro studies because its composition is representative of PCBs environmental pollution. We previously demonstrated that the exposure of bovine oocytes to A‐1254 during in vitro maturation (IVM) was detrimental not only to the maturation process but also induced a significant increase of polyspermy and a reduction of developmental competence. Therefore, we investigated whether A‐1254 acts on two processes that occur during IVM and may be related with its negative effects: maternal mRNA polyadenylation and cortical granules (CGs) migration and exocytosis. Bovine cumulus‐oocyte complexes (COCs) were exposed to 0.1 μg/ml of A‐1254 during IVM, a level of exposure known to affect oocyte maturation, fertilization, and developmental competence. Oocyte exposure to A‐1254 altered the poly(A) tail length of 5 out of 10 genes examined. PCBs effect on mRNA polyadenylation was different depending on the gene considered and resulted either in a shorter or in a longer poly(A) tail. At the end of maturation, Aroclor treated oocytes presented clustered CG in a significantly higher percentage than the control group. In addition, CG exocytosis after 8 hr of fertilization occurred at significantly lower extent in zygotes derived from the exposed group compared to control. Our results indicated that the lower developmental competence of oocytes exposed to PCBs during IVM can be related to the interaction of these contaminants with mechanisms regulating maternal mRNA storage in the ooplasm and normal CGs function. Mol. Reprod. Dev. 60: 535–541, 2001. © 2001 Wiley‐Liss, Inc.
Gradient system providing continuously variable field characteristics
Authors: Kimmlingen Ralph , Gebhardt Matthias , Schuster Johann , Brand Martin , Schmitt Franz , Haase Axel 
Published: August 2002

AbstractPeripheral nerve stimulation limits the use of whole‐body gradient systems capable of slew rates > 80 T/m/s and gradient strengths > 25 mT/m. The stimulation threshold depends mainly on the amplitude of the induced electric field in the patient's body, and thus can be influenced by changing the total magnetic flux of the gradient coil. A gradient system was built which allows continuous variation of the field characteristics in order to permit the use of full gradient performance without stimulation (slew rate 190–210 T/m/s, Gmax 32–40 mT/m). The system consists of a modular six‐channel gradient coil designed with a modified target field method, two three‐channel amplifiers, and a six‐channel gradient controller. It is demonstrated that two coils on one gradient axis can be driven by two amplifiers in parallel, without significant changes in image quality. Scaling of the field properties and stimulation threshold according to the current polarity and ratio of both coil sets was verified in both phantom and volunteer studies. Magn Reson Med 47:800–808, 2002. © 2002 Wiley‐Liss, Inc.
Mapping the absolute value of M0 using dipolar field effects
Authors: Gutteridge S. , Ramanathan C. , Bowtell R. 
Published: August 2002

AbstractThe ability to map the spatial variation of the absolute, rather than the relative value of the equilibrium magnetization could be advantageous in many areas of NMR. However, direct measurement of M0 is usually difficult because of the multiparametric dependence of the NMR signal. Here we propose a technique for mapping the spatial variation of the absolute value of M0, independent of relaxation weighting and flip angle calibration. This method, which works best at high field strengths, is based on the effect of the dipolar field due to the nuclear magnetization that is normally neglected in liquid‐state NMR. The experimental implementation of this sequence at 3.0 T is described, and its initial application to the measurement of the water content of brain tissue is outlined. Magn Reson Med 47:871–879, 2002. © 2002 Wiley‐Liss, Inc.
Mapping of retinal projections in the living rat using high‐resolution 3D gradient‐echo MRI with Mn2+‐induced contrast
Authors: Watanabe Takashi , Michaelis Thomas , Frahm Jens 
Published: August 2002

AbstractThis study describes the neuroaxonal tracing of the visual pathway in the living rat using high‐resolution T1‐weighted 3D gradient‐echo MRI (195 × 195 × 125 μm3) at 8, 24, 48, and 72 h after intraocular Mn2+ injection (0.1 μl of 1 M aqueous MnCl2). Best results were obtained at 24 h postinjection, revealing a continuous pattern of anterograde labeling from the retina, optic nerve, and chiasm to the contralateral optic tract, the dorsal and ventral lateral geniculate nucleus, the superior colliculus and its brachium, the olivary pretectal nucleus, the nucleus of the optic tract, and the suprachiasmatic nucleus. These results underline the feasibility of repeated MRI tract tracing in living animals after a single injection of Mn2+. The approach is expected to advance studies of neuroaxonal function in behaving animals with special emphasis on applications in developmental neurobiology. Magn Reson Med 46:424–429, 2001. © 2001 Wiley‐Liss, Inc.
Comparison of methods for reduction of lipid contamination for in vivo proton MR spectroscopic imaging of the brain
Authors: Ebel Andreas , Maudsley Andrew A. 
Published: August 2002

AbstractIn vivo proton MR spectroscopic imaging (MRSI) of human brain is complicated by the presence of a strong signal from subcutaneous lipids, which may result in signal contamination in metabolite images obtained following Fourier‐transform reconstruction. In this study, two approaches for reduction of lipid contamination—using postprocessing and additional data acquisition—are compared. The first uses extrapolation of k‐space information for subcutaneous lipid, which has been applied to data obtained using conventional fully phase‐encoded MRSI with circularly sampled k‐space or echo‐planar spectroscopic imaging (EPSI). The second uses a dual EPSI technique that combines multiple‐averaged central k‐space data with a single EPSI acquisition of additional information that is used for improved lipid reconstruction. Comparisons are carried out with data obtained from human brain in vivo at 1.5 T with short and medium TEs. Results demonstrate that the performance of both methods for reducing the effects of lipid contamination is similar, and that both are limited by the effects of instrumental instabilities and subject motion, which also depend on the acquisition method used. Magn Reson Med 46:706–712, 2001. © 2001 Wiley‐Liss, Inc.
Age‐related change in motor unit activation strategy in force production: A mechanomyographic investigation
Authors: Akataki Kumi , Mita Katsumi , Watakabe Makoto , Ito Kunihiko 
Published: August 2002

AbstractThis study was designed to examine the effect of increasing age on the recruitment and activation of motor units (MU) in the biceps brachii muscle, using the mechanomyogram (MMG)/force relationship during isometric ramp contractions. The relationships between the root mean squared amplitude (RMS) and mean power frequency (MPF) of the MMG and relative force (% MVC) in the elderly (male, n = 10, age = 69.8 ± 4.7 years, mean ± SD) were markedly different from those in the young group (male, n = 15, age = 22.7 ± 1.8 years). In elderly individuals, the RMS increased progressively with force up to 57.6 ± 3.4% MVC, when a brief rapid increase was followed by a stable trend beyond 63.6 ± 3.7% MVC. The MPF increased slowly up to 59.4 ± 2.3% MVC; after a temporary reduction from 59.4% to 64.3 ± 2.0% MVC, it then increased progressively again. In conjunction with absolute force (Fabs), both the RMS and MPF in the elderly were smaller than those in the young group throughout the submaximal levels of force exerted. The results reflect an alteration in MU activation strategy, with a predominant role for MUs with slow‐twitch fibers and an effective fused tetanus induced at lower firing rate of the MUs, resulting from age‐related neuromuscular changes. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002 DOI 10.1002/mus.10076
Inventory cost impact of order processing priorities based on demand uncertainty
Authors: Iyer Ananth. V. 
Published: August 2002

AbstractWe evaluate an approach to decrease inventory costs at retail inventory locations that share a production facility. The retail locations sell the same product but differ in the variance of retail demand. Inventory policies at retail locations generate replenishment orders for the production facility. The production facility carries no finished goods inventory. Thus, production lead time for an order is the sojourn time in a single server queueing system. This lead time affects inventory costs at retail locations. We examine the impact of moving from a First Come First Served (FCFS) production rule for orders arriving at the production facility to a rule in which we provide non‐preemptive priority (PR) to orders from retail locations with higher demand uncertainty. We provide three approximations for the ratio of inventory costs under PR and FCFS and use them to identify conditions under which PR decreases retail inventory costs over FCFS. We then use a Direct Approach to establish conditions when PR decreases retail inventory costs over FCFS. We extend the results to orders from locations that differ in the mean and variance of demand uncertainty. The analysis suggests that tailoring lead times to product demand characteristics may decrease system inventory costs. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 376–390, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10016
Many‐player rendezvous search: Stick together or split and meet?
Authors: Thomas L.C. , Pikounis M. 
Published: August 2002

AbstractRendezvous search finds the strategies that players should use in order to find one another when they are separated in a region. Previous papers have concentrated on the case where there are two players searching for one another. This paper looks at the problem when there are more than two players and concentrates on what they should do if some but not all of them meet together. It looks at two strategies—the stick together one and the split up and meet again one. This paper shows that the former is optimal among the class of strategies which require no memory and are stationary, and it gives a method of calculating the expected rendezvous time under it. However, simulation results comparing both strategies suggest that in most situations the split up and meet again strategy which requires some memory leads to faster expected rendezvous times. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:710–721, 2001
Sequential proton MRS study of brain metabolite changes monitored during a complete pathological cycle of demyelination and remyelination in a lysophosphatidyl choline (LPC)‐induced experimental demyelinating lesion model
Authors: Degaonkar M. N. , Khubchandhani M. , Dhawan J. K. , Jayasundar R. , Jagannathan N. R. 
Published: August 2002

AbstractMetabolite changes in rat brain internal capsule (ic) area were monitored using volume localized in vivo proton MR spectroscopy (MRS) in a lysophosphatidyl choline (LPC)‐induced experimental demyelinating lesion model of multiple sclerosis (MS), during the early phase (pre‐acute) as well as during the complete pathological cycle of de‐ and re‐myelination processes. The N‐acetyl aspartate (NAA) peak showed reduction during the early phase of the lesion progression (demyelination) until day 10 and increased thereafter during remyelination. However, choline (Cho) and lipid resonances showed increased signal intensity during the early phase and decreased during remyelination. A progressive reduction of the NAA/Cr metabolite ratio in lesioned rats was observed during demyelination (up to day 10) compared with before lesion (control), and the value increased thereafter during remyelination (from day 15). During this period, however, the Cho/Cr ratio was a higher until day 10 and subsequently declined and was close to that calculated before lesion creation. The changes in NAA/Cr and Cho/Cr metabolite ratios correspond to changes in the individual metabolite peaks such as NAA and Cho. The increase in the intensity of the choline resonance during the early phase is indicative of the onset of an inflammatory demyelination process, and its rapid decrease thereafter is due to reduction in the inflammatory process associated with remyelination. Similarly, the increase in the intensity of lipids during the pre‐acute stage of the lesion is attributed to active demyelination, which significantly decreased during remyelination. These MR results correlate well with the histology data obtained. Copyright © 2002 John Wiley & Sons, Ltd.
Perineal muscles and motoneurons are sexually monomorphic in the naked mole‐rat (Heterocephalus glaber)
Authors: Peroulakis Maria E. , Goldman Bruce , Forger Nancy G. 
Published: August 2002

AbstractNaked mole‐rats are eusocial mammals that live in colonies with a single breeding female and one to three breeding males. All other members of the colony, known as subordinates, are nonreproductive and exhibit few sex differences in behavior or genital anatomy. This raises questions about the degree of sexual differentiation in subordinate naked mole‐rats. The striated perineal muscles associated with the phallus [the bulbocavernosus (BC), ischiocavernosus (IC), and levator ani (LA) muscles], and their innervating motoneurons, are sexually dimorphic in all rodents examined to date. We therefore asked whether perineal muscles and motoneurons were also sexually dimorphic in subordinate naked mole‐rats. Muscles similar to the LA and IC of other rodents were found in naked mole‐rats of both sexes. No clear BC muscle was identified, although a large striated muscle associated with the urethra in male and female naked mole‐rats may be homologous to the BC of other rodents. There were no sex differences in the volumes of the LA, IC, or the urethral muscles. Motoneurons innervating the perineal muscles were identified by retrograde labeling with cholera‐toxin‐conjugated horseradish peroxidase. All perineal motoneurons were found in a single cluster in the ventrolateral lateral horn, in a position similar to that of Onuf's nucleus of carnivores and primates. There was no sex difference in the size or number of motoneurons in Onuf's nucleus of naked mole‐rats. Thus, unlike findings in any other mammal, neither the perineal muscles nor the perineal motoneurons appear to be sexually differentiated in subordinate naked mole‐rats. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 33–42, 2002
A basic thin shell triangle with only translational DOFs for large strain plasticity
Authors: Flores Fernando G. , Oñate Eugenio 
Published: August 2002

AbstractA simple finite element triangle for thin shell analysis is presented. It has only nine translational degrees of freedom and is based on a total Lagrangian formulation. Large strain plasticity is considered using a logarithmic strain–stress pair. A plane stress isotropic behaviour with an additive decomposition of elastic and plastic strains is assumed. A hyperelastic law is considered for the elastic part while for the plastic part a von Mises yield function with non‐linear isotropic hardening is adopted. The element is an extension of a previous similar rotation‐free triangle element based upon an updated Lagrangian formulation with hypoelastic constitutive law. The element termed BST (for basic shell triangle) has been implemented in an explicit (hydro‐) code adequate to simulate sheet‐stamping processes and in an implicit static/dynamic code. Several examples are shown to assess the performance of the present formulation. Copyright © 2001 John Wiley & Sons, Ltd.
Micromechanical analysis of quasi‐brittle materials using fracture‐based interface elements
Authors: Carol Ignacio , López Carlos M. , Roa Olga 
Published: August 2002

AbstractA microstructural model for the mechanical behaviour of quasi‐brittle materials is developed and verified for concrete and bone specimens. The model is based on interface elements equipped with a constitutive law representing non‐linear fracture, while continuum elements remain linear elastic. The interface constitutive model is implemented with a sub‐stepping scheme. Non‐linear geometric effects due to large displacements are included in the model by means of an incremental Lagrangian formulation, although strains in the continuum and relative displacements in the interfaces are assumed to remain small. An arc‐length procedure is used to ensure convergence during the highly non‐linear behaviour in the post‐peak regime. Concrete and bone specimens are idealized as two‐phase particle composites and are discretized into finite elements, including interface elements along the main potential crack paths. The numerical results in tension and compression are described and compared with experimental observations. The need of considering non‐linear geometric effects in this type of calculations is also discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Higher‐order boundary element methods for transient diffusion problems. Part II: Singular flux formulation
Authors: Dargush G. F. , Grigoriev M. M. 
Published: August 2002

AbstractA boundary element method (BEM) for transient heat diffusion phenomena presented in Part I is extended to problems involving instantaneous rise of temperature on a portion of the boundary. The new boundary element formulation involves the use of an infinite flux function in order to properly capture the singular response of the flux. It is shown that the conventional finite flux BEM formulation, as well as a commercial FEM code, results in a large first‐time‐step numerical error that cannot be reduced by mesh or time‐step refinement. The use of the singular flux formulation for BEM demonstrates an extremely high level of accuracy for the one‐dimensional case, and a significant improvement in the solutions within a two‐dimensional representation. The additional errors arising due to improper time interpolation of the temperature on the boundaries adjacent to the singular flux boundary are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
How coaching can enhance your brand as a manager
Authors: Hunt James M. , Weintraub Joseph 
Published: August 2002

AbstractManagers who coach their employees become known as good managers to work for, developers of talent, and achievers
of business results. They also become better leaders in the process. The average manager, however, doesn't
coach, believing it would take too much time or be a waste of effort. Such barriers, however, are more psychological
than real, and represent an expression of the status quo. The fact is that coaching managers behave differently, and
that contributes to their brand. The bottom line: Since most managers don't coach, those who do actively help
their employees learn and grow have a competitive advantage, one that can enhance their careers. © 2002
Wiley Periodicals, Inc.
A posteriori error estimates for FEM with violated Galerkin orthogonality
Authors: Angermann Lutz 
Published: August 2002

AbstractThis article investigates Petrov‐Galerkin discretizations of operator equations with linearly stable operators, where the residual does not belong to the annihilator W of the discrete test space Wh. Conforming and nonconforming methods are considered separately, and for the treatment of the nonconforming situation the concept of elliptic lifting is introduced. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 241–259, 2002; DOI 10.1002/num.1005
Evaluating the impact of peer, nurse case‐managed, and standard HIV risk‐reduction programs on psychosocial and health‐promoting behavioral outcomes among homeless women
Authors: Nyamathi Adeline , Flaskerud Jacqueline H. , Leake Barbara , Dixon Elizabeth L. , Lu Ake 
Published: August 2002

AbstractInvestigators examined the 6‐month impact of three cognitive–behavioral HIV risk‐reduction programs on behavioral factors (substance use and sexual risk behaviors) and cognitive and psychological resources of 325 women who resided in emergency or sober‐living shelters and their 308 intimate sexual partners. Participants were randomized by shelter to a peer‐mentored, a nurse case‐managed, or a standard care HIV risk‐reduction program. Significant improvements were observed in all groups in all behavioral factors and cognitive and psychological resources except for self‐esteem. Participants in the peer‐mentored and nurse case‐managed groups did not differ significantly from the standard group in self‐esteem, life satisfaction, psychological well‐being, use of noninjection drugs, sex with multiple partners, and unprotected sex at 6 months (n = 633). It was concluded that a standard approach by health care professionals appears to effectively modify HIV risk behaviors for a majority of homeless participants and may have important economic and policy implications. Further, the impact of short‐term programs that address psychological vulnerabilities of impoverished populations needs to be studied further. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24:410–422, 2001