bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional organization of the suprachiasmatic nucleus of Xenopus laevis in relation to background adaptation
Authors: Kramer Bianca M.R. , Welting Joyce , Berghs Constance A.F.M. , Jenks Bruce G. , Roubos Eric W. 
Published: August 2002

AbstractThe process of background adaptation in the toad Xenopus laevis is controlled by neurons in the suprachiasmatic nucleus (SC) that inhibit the release of α‐melanophore‐stimulating hormone from the neuroendocrine melanotrope cells in the pituitary gland. We have identified the structural and functional organization of different neuropeptide Y (NPY)‐containing cell groups in the Xenopus SC in relation to background adaptation. A ventrolateral, a dorsomedial, and a caudal group were distinguished, differing in location as well as in number, size, and shape of their cells. They also show different degrees of NPY immunoreactivity in response to different background adaptation conditions. In situ hybridization using a Xenopus mRNA probe for the exocytosis protein DOC2 revealed that melanotrope cells of black‐adapted animals have a much higher expression of DOC2‐mRNA than white‐adapted ones. This establishes that the degree of DOC2‐mRNA expression is a good parameter to measure cellular secretory activity in Xenopus. We show that in the ventrolateral SC group, more NPY‐positive neurons express DOC2‐mRNA in white‐ than in black‐adapted animals. In contrast, NPY‐positive neurons in the dorsomedial group have a high secretory activity under the black‐adaptation condition. We propose that in black‐adapted animals, NPY‐positive neurons in the ventrolateral group, known to inhibit the melanotrope cells in white‐adapted animals synaptically, are inhibited by NPY‐containing interneurons in the dorsmedial group. NPY‐positive neurons in the caudal group have similar secretory dynamics as the dorsomedial NPY neurons, indicating that they also play a role in background adaptation, distinct from that exerted by the ventrolateral and dorsomedial group. J. Comp. Neurol. 432:346–355, 2001. © 2001 Wiley‐Liss, Inc.
Immunocytochemical localization of opsin, visual arrestin, myosin III, and calmodulin in Limulus lateral eye retinular cells and ventral photoreceptors
Authors: Battelle Barbara‐Anne , Dabdoub Alain , Malone Michael A. , Andrews Anne W. , Cacciatore Chelsi , Calman Bruce G. , Smith W. Clay , Payne Richard 
Published: August 2002

AbstractThe photoreceptors of the horseshoe crab Limulus polyphemus are classical preparations for studies of the photoresponse and its modulation by circadian clocks. An extensive literature details their physiology and ultrastructure, but relatively little is known about their biochemical organization largely because of a lack of antibodies specific for Limulus photoreceptor proteins. We developed antibodies directed against Limulus opsin, visual arrestin, and myosin III, and we have used them to examine the distributions of these proteins in the Limulus visual system. We also used a commercial antibody to examine the distribution of calmodulin in Limulus photoreceptors. Fixed frozen sections of lateral eye were examined with conventional fluorescence microscopy; ventral photoreceptors were studied with confocal microscopy. Opsin, visual arrestin, myosin III, and calmodulin are all concentrated at the photosensitive rhabdomeral membrane, which is consistent with their participation in the photoresponse. Opsin and visual arrestin, but not myosin III or calmodulin, are also concentrated in extra‐rhabdomeral vesicles thought to contain internalized rhabdomeral membrane. In addition, visual arrestin and myosin III were found widely distributed in the cytosol of photoreceptors, suggesting that they have functions in addition to their roles in phototransduction. Our results both clarify and raise new questions about the functions of opsin, visual arrestin, myosin III, and calmodulin in photoreceptors and set the stage for future studies of the impact of light and clock signals on the structure and function of photoreceptors. J. Comp. Neurol. 435:211–225, 2001. © 2001 Wiley‐Liss, Inc.
Comparative fine structural distribution of endopeptidase 24.15 (EC3.4.24.15) and 24.16 (EC3.4.24.16) in rat brain
Authors: Fontenele‐Neto José Domingues , Massarelli Eduardo Ernst , Gurgel Garrido Paula Amaral , Beaudet Alain , Ferro Emer Suavinho 
Published: August 2002

AbstractEndopeptidase 24.15 (EP24.15) and 24.16 (EP24.16) are closely related metalloendopeptidases implicated in the metabolism of several neuropeptides and widely expressed in mammalian brain. To gain insight into the functional role of these two enzymes in the central nervous system, we examined their cellular and subcellular distribution in rat brain by using electron microscopic immunogold labeling. In all areas examined, EP24.15 and EP24.16 immunoreactivity were observed in selective subpopulations of neuronal and glial cells. Subcellular localization of EP24.15 in neurons revealed that this enzyme was predominantly concentrated in the nucleus, whereas EP24.16 was almost exclusively cytoplasmic. The amount of EP24.15 found in the nucleus was inversely correlated with that found in the cytoplasm, suggesting that the enzyme could be mobilized from one compartment to the other. Within the cytoplasm, EP24.15 and EP24.16 immunoreactivity showed comparable distributional patterns. Both enzymes were detected throughout perikarya and dendrites, as well as within axons and axon terminals. In all neuronal compartments, EP24.15 and EP24.16 showed a major association with membranes of neurosecretory elements, including Golgi cisternae, tubulovesicular organelles, synaptic vesicles, and endosomes. However, whereas EP24.15 always faced the cytoplasmic face of the membranes, EP24.16 was observed on both cytoplasmic and luminal sides, suggesting that the latter was more likely to contribute to the processing of peptides or to the degradation of internalized ligands. Taken together, the present results suggest that EP24.15 could play a major role in the hydrolysis of intranuclear substrates, whereas EP24.16 would be predominantly involved in the processing and inactivation of signaling peptides. J. Comp. Neurol.438:399–410, 2001. © 2001 Wiley‐Liss. Inc.
Postnatal development of catecholamine inputs to the paraventricular nucleus of the hypothalamus in rats
Authors: Rinaman Linda 
Published: August 2002

AbstractAdrenergic and noradrenergic neural projections to the paraventricular nucleus of the hypothalamus (PVN) contribute importantly to viscerosensory modulation of pituitary hormone secretion. Immaturity of ascending catecholamine pathways may partially underlie the documented hyporesponsiveness of PVN neurosecretory cells to certain interoceptive stimuli in rats during the first few weeks of postnatal development. To explore this possibility, the present study compared the distribution and number of dopamine‐β‐hydroxylase (DBH)‐ and phenylethanolamine‐N‐methyltransferase (PNMT)‐positive neurons projecting to the PVN in newborn and adult rats. In addition, a quantitative analysis of DBH‐ and PNMT‐immunoreactive fibers in the medial parvocellular subnucleus, dorsal division (PVNmpd) and posterior magnocellular subnucleus, lateral division (PVNpml) was performed in adult rats and in developing rats on postnatal day (P)1, P7, P14, and P21. The numbers of PVN‐projecting neurons in the A1, C1, A2/C2, C3, or A6 catecholamine cell groups were similar in newborn and adult rats, as were the proportions of PVN‐projecting neurons in each region that were PNMT‐positive. However, fewer PVN‐projecting neurons in the C1 and C3 regions expressed DBH immunolabeling in newborn rats compared to adults. DBH immunolabeling increased progressively in the PVNmpd and PVNpml between postnatal days P1 and P21, when adult‐like levels were achieved. Conversely, PNMT immunolabeling in the same PVN subdivisions was most dense at P1, gradually decreasing to adult‐like levels by P21. These dynamic developmental changes in catecholamine synthetic enzyme immunolabeling densities in the PVN may reflect functional changes in noradrenergic and adrenergic signaling capacity in rats during the first few weeks of postnatal development. J. Comp. Neurol. 438:411–422, 2001. © 2001 Wiley‐Liss, Inc.
Localization of the presynaptic cytomatrix protein Piccolo at ribbon and conventional synapses in the rat retina: Comparison with Bassoon
Authors: Dick Oliver , Hack Iris , Altrock Wilko Detlef , Garner Craig Curtis , Gundelfinger Eckart Dieter , Brandstätter Johann Helmut 
Published: August 2002

AbstractIn recent years significant progress has been made in the elucidation of the molecular assembly of the postsynaptic density at synapses, whereas little is known as yet about the components of the presynaptic active zone. Piccolo and Bassoon, two structurally related presynaptic cytomatrix proteins, are highly concentrated at the active zones of both excitatory and inhibitory synapses in rat brain. In this study we used immunocytochemistry to examine the cellular and ultrastructural localization of Piccolo at synapses in the rat retina and compared it with that of Bassoon. Both proteins showed strong punctate immunofluorescence in the outer and the inner plexiform layers of the retina. They were found presynaptically at glutamatergic ribbon synapses and at conventional GABAergic and glycinergic synapses. Although the two proteins were coexpressed at all photoreceptor ribbon synapses and at some conventional amacrine cell synapses, at bipolar cell ribbon synapses only Piccolo was present. Our data demonstrate similarities but also differences in the molecular composition of the presynaptic apparatuses of the synapses in the retina, differences that may account for the functional differences observed between the ribbon and the conventional amacrine cell synapses and between the photoreceptor and the bipolar cell ribbon synapses in the retina. J. Comp. Neurol. 439:224–234, 2001. © 2001 Wiley‐Liss, Inc.
Transforming growth factor‐α‐induced cellular changes in organotypic cultures of juvenile, amikacin‐treated rat organ of corti
Authors: Daudet Nicolas , Ripoll Chantal , Lenoir Marc 
Published: August 2002

AbstractHair cell losses in the mammalian cochlea following an ototoxic insult are irreversible. However, past studies have shown that amikacin treatment in rat cochleae resulted in the transient presence of atypical Deiters' cells (ACs) in the damaged organ of Corti. These ACs arise through a transformation of Deiters' cells, which produce, at their apical pole, densely packed microvilli reminiscent of early‐differentiating stereociliary bundles. The ACs do not, however, express typical hair cell markers such as parvalbumin or calbindin. The present study was designed to determine whether specific growth factors could influence the survival and differentiation of these ACs and stimulate hair cell regeneration processes in vitro. Apical‐medial segments of organ of Corti of juvenile amikacin‐treated rats were established as organotypic cultures, and the effects of epidermal growth factor (EGF), insulin‐like growth factor 1 (IGF‐1), transforming growth factor‐α (TGFα), and retinoic acid were studied using morphological and molecular approaches. Our results indicate that TGFα supports the survival of the damaged organ of Corti and influences ACs differentiation in vitro, possibly acting through reorganization of the actin cytoskeleton. These effects could be directly mediated through activation of the EGF receptor, which is expressed by supporting cells in the mature organ of Corti. TGFα does not, however, allow the ACs to progress towards a hair cell phenotype. J. Comp. Neurol. 442:6–22, 2002. © 2002 Wiley‐Liss, Inc.
Localization and characterization of NPY/PYY receptors in rat frontoparietal cortex during development
Authors: Leroux Philippe 
Published: August 2002

AbstractNeuropeptide Y (NPY) is present in most cerebrocortical areas during fetal and postnatal development. In the rat frontal cortex, a dense radial fiber network containing NPY immunoreactivity is observed transiently as early as embryonic day 17 (E17) and disappears at the end of the first postnatal week. We have investigated the distribution of NPY receptors in the frontoparietal cortex at 13 stages of development, from E15 fetuses to adults, by in vitro autoradiography, using 125I‐pPYY as a radioligand. Quantitative receptor density was measured through all cortical layers at each developmental stage. Pharmacological identification of 125I‐pPPY binding sites was made by competition experiments using pNPY or [Leu31,Pro34]pNPY and pNPY13‐36, as selective competitors for Y1 and Y2 receptors, respectively. NPY receptors were first detected in the cerebral cortex at low densities at E19 in a thin layer of tissue corresponding to the inner half of the intermediate zone (IZ) and the upper ventricular zone (VZ). The neuroepithelium did not contain binding sites. High densities of sites were observed by E21 onward to P10 in the deep cortical layers corresponding to the IZ and layers V–VI. A decreasing gradient of receptor density was observed from layer VI to the marginal zone (layer I). The distribution of NPY receptors does not match with the perikarya of transient NPY‐immunoreactive neurons located in the cortical plate but does coincide with their axonal extension. The receptor density decreased abruptly between P10 and P12 in deep layers, whereas a moderate expression of binding sites is detected from P10 to P12 in layers I–III. By P14, the binding level was the lowest observed in the postnatal period. From P21 onward, receptors were observed in superficial layers I–III, and their density rose by two‐ to threefold up to adulthood. Competition studies indicated that the NPY receptors located in the deep cortical layers of the E21 or P1 rat cortex exhibit Y2 receptor type characteristics. The binding sites detected in the superficial layers from P10 to P12 rats also show Y2 receptors characteristics, unlike the NPY receptors in layers II–III of the adult, which behave like Y1 receptors. These data show that different NPY receptor types are successively expressed in specific layers during late gestation and early postnatal life in the rat frontoparietal cortex. J. Comp. Neurol. 442:35–47, 2002. © 2002 Wiley‐Liss, Inc.
Rotation shape functions for a low‐order quadrilateral plate element with mid‐side rotations
Authors: Crisfield M. A. , Tan D. 
Published: August 2002

AbstractThis short paper re‐visits an earlier paper by Nagtegaal and Slater in which a quadrilateral shell element was derived which used similar kinematics to that in the Morley facet shell. Because the paper seems to be relatively unknown and also is rather long and involved, we here concentrate on the plate‐bending aspects of the element and describe the shape functions. Copyright © 2001 John Wiley & Sons, Ltd.
Efficient large deflection analysis of elasto‐plastic thin shells of revolution
Authors: Pajunen Sami 
Published: August 2002

AbstractThe paper presents an extension of a stress resultant based axisymmetric shell element by Reissner to the elasto‐plastic computations. In the elastic range, the element exhibits exact kinematics for large displacements and rotations thus enabling the use of large increments in the global equilibrium path continuation. In order to preserve this desired property also in the elasto‐plastic range, the general closest point projection algorithm is utilized for the elasto‐plastic stress increment computation. In the case of the used element, consistent linearization of the stress updating algorithm results in a very simple form so that the element offers an efficient and computationally cheap approach to the large deflection elasto‐plastic axisymmetric shell problems. Copyright © 2001 John Wiley & Sons, Ltd.
Optimal time integration parameters for elastodynamic contact problems
Authors: Czekanski A. , El‐Abbasi N. , Meguid S. A. 
Published: August 2002

AbstractIn this paper, we employ the generalized‐α time integration scheme for treating elastodynamic contact problems. The criteria invoked for the selection of the four time integration parameters are motivated by our desire to ensure that the solution is unconditionally stable, second‐order accurate, provides optimal high‐frequency dissipation and preserves the energy and momentum transfer in dynamic rigid impact problems. New closed‐form expressions for the time integration parameters are determined in terms of user‐specified high‐frequency spectral radius. The selected parameters help in avoiding the spurious high‐frequency modes, which are present in the traditional Newmark method. Copyright © 2001 John Wiley & Sons, Ltd.
Application of the generalized differential quadrature rule to eighth‐order differential equations
Authors: Wu T. Y. , Liu G. R. 
Published: August 2002

AbstractThis work extends the application of the generalized differential quadrature rule (GDQR) to an eighth‐order boundary‐value differential equation with four boundary conditions at boundaries. The differential quadrature expression and explicit weighting coefficients for the eighth‐order differential equation are formulated for a first time to implement the GDQR more accurately. A circular cylindrical single‐barrel roof is employed as an example. The numerical results show good accuracy and convergence with only a few sampling points. The application of the GDQR is straightforward and has clear advantages in the implementation of multiple boundary conditions over the existing δ‐point technique. The GDQR has demonstrated itself as a general numerical method to solve high‐order differential equation with multiple boundary conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Finite element modelling of rock alteration and metamorphic process in hydrothermal systems
Authors: Zhao Chongbin , Hobbs B. E. , Mühlhaus H. B. , Ord A. 
Published: August 2002

AbstractWe use the finite element method to simulate the rock alteration and metamorphic process in hydrothermal systems. In particular, we consider the fluid–rock interaction problems in pore‐fluid saturated porous rocks. Since the fluid–rock interaction takes place at the contact interface between the pore‐fluid and solid minerals, it is governed by the chemical reaction which usually takes place very slowly at this contact interface, from the geochemical point of view. Due to the relative slowness of the rate of the chemical reaction to the velocity of the pore‐fluid flow in the hydrothermal system to be considered, there exists a retardation zone, in which the conventional static theory in geochemistry does not hold true. Since this issue is often overlooked by some purely numerical modellers, it is emphasized in this paper. The related results from a typical rock alteration and metamorphic problem in a hydrothermal system have shown not only the detailed rock alteration and metamorphic process, but also the size of the retardation zone in the hydrothermal system. Copyright © 2001 John Wiley & Sons, Ltd.
A quality of service driven concurrency framework for object‐based middleware
Authors: Coulson Geoff , Moonian Oveeyen 
Published: August 2002

AbstractThreads play a key role in object‐based middleware platforms. Implementers of such platforms can select either kernel or user‐level threads, but neither of these options are ideal. In this paper we introduce Application Scheduler Contexts (ASCs) which flexibly combine both types of thread and thereby attempt to exploit the advantages of each. Multiple ASCs can co‐exist, each with their own concurrency semantics and scheduling policy. ASCs also support quality of service (QoS) configurability, and define their own QoS schema. We show how ASCs can be efficiently implemented and how they can usefully be exploited in middleware environments. We also provide a quantitative evaluation that demonstrates the feasibility of the ASC concept in performance terms. Copyright © 2002 John Wiley & Sons, Ltd.
Mathematical fortune‐telling
Authors: Hatamian Tim S. 
Published: August 2002

AbstractThis is an informal introduction to the physics of dynamical systems and chaos at the level of elementary college calculus and analytic geometry. Terms like state‐vector, phase‐space, and strange attractor are defined and illustrated. Subsequently, we describe a method to produce forecasts for the behavior of complex nonlinear systems using the past behavior of the system. Finally, examples are provided to illustrate the practical utility of the method. Examples include: forecasting of presidential elections; the logistic, and predator‐prey time series; sun spot numbers; human body fat; and arbitrage trading in stocks. Other types of applications in lending, insurance, quality control, noise‐reduction, and pattern recognition are also good candidates for this method. Details on various aspects of the method are given in end notes suited for readers other than the complete beginner.
Relations between anxiety disorders and fear of childbirth during late pregnancy
Authors: Zar Margareta , Wijma Klaas , Wijma Barbro 
Published: August 2002

AbstractIn a group of late pregnant women we investigated the prevalence of extreme fear of childbirth and anxiety disorders, both assessed by means of diagnostic interviews. We also explored the relation between anxiety disorders and extreme fear of childbirth on the one hand and fear of childbirth, as measured by means of the Wijma Delivery Expectancy/Experience Questionnaire (W‐DEQ), on the other hand. A subgroup of women (2.4%) fulfilled the criteria for a phobia‐like fear of childbirth. Anxiety disorders were related to fear of childbirth, as measured by the W‐DEQ. The group of women with extreme fear of childbirth (with or without anxiety disorders) had obviously the highest W‐DEQ scores. But also in the group of women with anxiety disorders only the W‐DEQ scores were high. Clinical assessment of anxiety disorders among pregnant women should be considered, above all in women who report fear of the anticipated delivery. Copyright © 2002 John Wiley & Sons, Ltd.
Exact sampled‐data analysis of quasi‐resonant converters with finite filter inductance and capacitance
Authors: Fang Chung‐Chieh 
Published: August 2002

AbstractPrevious models of quasi‐resonant converters generally use averaging and assume infinite filter inductance and capacitance to reduce circuit complexity, but at the expense of accuracy. In this paper, exact sampled‐data modelling is used. A general block diagram model applicable to various topologies of quasi‐resonant converters is proposed. Large‐signal analysis, steady‐state analysis and small‐signal analysis are all studied. They agree closely with the experimental results in the literature. Compared with the averaging approach, the sampled‐data approach is more systematic and accurate. Copyright © 2001 John Wiley & Sons, Ltd.