bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modular Synthesis of Functional Block Copolymers
Authors: Justynska Justyna , Schlaad Helmut 
Published: August 2004

AbstractSummary: The free‐radical addition of ω‐functional mercaptans to the vinyl double bonds of 1,2‐polybutadiene‐block‐poly(ethylene oxide) copolymers was used for modular synthesis of well‐defined functional block copolymers. The modification reaction proceeds smoothly and yields quantitatively functionalized block copolymers (1H NMR and FT‐IR spectroscopy) without disturbing the molecular‐weight distribution of the parent copolymer (PDI < 1.09, size exclusion chromatography).The modular synthetic pathway towards the functional block copolymers reported here.imageThe modular synthetic pathway towards the functional block copolymers reported here.
Metoclopramide‐induced tardive dyskinesia in an infant
Authors: Mejia Nicte I. , Jankovic Joseph 
Published: August 2004

AbstractWe describe a 1‐year‐old girl who developed orofaciolingual stereotypy at age 2 months after a 17‐day treatment with metoclopramide for gastroesophageal reflux. The stereotypy, documented by sequential videos, persisted for at least 9 months after the drug was discontinued. This patient represents the first documented case of tardive dyskinesia in an infant. We also review previous reports of tardive dyskinesia in children. © 2004 Movement Disorder Society
Rebound psychosis: Effect of discontinuation of antipsychotics in Parkinson's disease
Authors: Fernandez Hubert H. , Trieschmann Martha E. , Okun Michael S. 
Published: August 2004

AbstractTo determine whether psychiatrically stable patients with a history of drug‐induced psychosis could be successfully weaned off their antipsychotic drug, we offered consecutive Parkinson disease (PD) patients on quetiapine or clozapine, who were free of any on‐going psychosis, to be slowly weaned off their antipsychotic drug. Before the study was aborted 6 PD patients (mean age, 78 years) with an average antipsychotic exposure of 20 months (5 on quetiapine, 1 on clozapine) were enrolled. After the antipsychotic agent was discontinued, psychosis recurred in 5 of 6 patients. In 3 patients the “rebound psychosis” was worse than the original psychotic episode and required subsequent higher antipsychotic medication doses. © 2004 Movement Disorder Society
Effects of levodopa and COMT inhibitors on plasma homocysteine in Parkinson's disease patients
Authors: Lamberti Paolo , Zoccolella Stefano , Iliceto Giovanni , Armenise Elio , Fraddosio Angela , De Mari Michele , Livrea Paolo 
Published: August 2004

AbstractHomocysteine (Hcy) is a risk factor for vascular diseases, cognitive impairment, and dementia. Elevated plasma concentrations of Hcy have been found recently in Parkinson's disease (PD) patients treated with levodopa, suggesting that levodopa is a cause of hyperhomocysteinemia (HHcy). The mechanism underlying HHcy in PD is the O‐methylation of levodopa catalyzed by catechol‐O‐methyltransferase (COMT) that produces S‐adenosylhomocysteine, which is hydrolyzed rapidly to Hcy. COMT inhibitors (COMT‐I) are used currently in the treatment of PD; however, no study has assessed the effects of COMT‐I administration on Hcy concentrations in PD patients. We compared plasma levels of Hcy, B12, and folate in 26 PD patients treated with levodopa, 20 PD patients treated with levodopa + COMT‐I, and 32 controls. No significant differences were found in vitamin B12 levels, whereas folate concentrations were significantly lower in the levodopa‐treated group. Plasma Hcy was increased significantly in the two groups of PD patients and was significantly lower in the group treated with levodopa + COMT‐I. Statistical analysis showed that the difference in mean Hcy levels observed among PD patients was related to the addition of COMT‐I, rather than to folate concentrations. We conclude that levodopa treatment increases plasma Hcy and the addition of COMT‐I effectively reduces HHcy. © 2004 Movement Disorder Society
Paroxysmal non‐kinesigenic dyskinesia in antiphospholipid syndrome
Authors: Engelen Marc , Tijssen Marina A.J. 
Published: August 2004

AbstractWe report on a patient with a mixed movement disorder classifiable as a paroxysmal nonkinesigenic dyskinesia, occurring as the first manifestation of primary antiphospholipid syndrome (PAPS). Possible pathophysiology is discussed based on recent literature, and we stress that PAPS must be considered in movement disorders of a paroxysmal nature. © 2004 Movement Disorder Society
Isolated tongue tremor after gamma knife radiosurgery for acoustic schwannoma
Authors: Chung Sun J. , Im Joo‐Hyuk , Lee Jae‐Hong , Cho A‐Hyun , Kwon Miseon , Lee Myoung C. 
Published: August 2004

AbstractWe describe a patient who had an isolated tongue tremor with an audible click after gamma knife radiosurgery for acoustic schwannoma. The nature of the tongue tremor was clearly demonstrated by videofluoroscopy. The possible pathogenic mechanisms are discussed. © 2004 Movement Disorder Society
A doubly critical degenerate parabolic problem
Authors: Winkler Michael 
Published: August 2004

AbstractIt is shown that the Dirichlet problem for

where Ω⊂ℝn is critical in that it has first eigenvalue one, is globally solvable for any continuous positive initial datum vanishing at ∂Ω. Moreover, for p<3 all solutions are bounded and tend to some nonnegative eigenfunction of the Laplacian as t→∞, while if p⩾3 then there are both bounded and unbounded solutions. Finally, it is shown that unlike the case p∈[0,1), all steady states are unstable if p⩾1. Copyright © 2004 John Wiley & Sons, Ltd.
Existence and uniform decay for Euler–Bernoulli beam equation with memory term
Authors: Park Jong Yeoul , Kim Joung Ae 
Published: August 2004

AbstractIn this article we prove the existence of the solution to the mixed problem for Euler–Bernoulli beam equation with memory term. The existence is proved by means of the Faedo–Galerkin method and the exponential decay is obtained by making use of the multiplier technique combined with integral inequalities due to Komornik. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling poroelastic hollow cylinder experiments with realistic boundary conditions
Authors: Jourine S. , Valkó P. P. , Kronenberg A. K. 
Published: August 2004

AbstractA general poroelastic solution for axisymmetrical plane strain problems with time dependent boundary conditions is developed in Laplace domain. Time‐domain results are obtained using numerical inversion of the Laplace transform. Previously published solutions can be considered as special cases of the proposed solution. In particular, we could reproduce numerical results for solid and hollow poroelastic cylinders with suddenly applied load/pressure (Rice and Cleary, Rev. Geophys. Space Phys. 1976; 14:227; Schmitt, Tait and Spann, Int. J. Rock Mech. Min. Sci. 1993; 30:1057; Cui and Abousleiman, ASCE J. Eng. Mech. 2001; 127:391).The new solution is used to model laboratory tests on thick‐walled hollow cylinders of Berea sandstone subjected to intensive pressure drawdown. In the experiments, pressure at the inner boundary of the hollow cylinder is observed to decline exponentially with a decay constant of 3–5 1/s.It is found that solutions with idealized step‐function type inner boundary conditions overestimate the induced tensile radial stresses considerably. Although basic poroelastic phenomena can be modelled properly at long time following a stepwise change in pressure, realistic time varying boundary conditions predict actual rock behaviour better at early time. Experimentally observed axial stresses can be matched but appear to require different values for α and ν than are measured at long time.The proposed solution can be used to calculate the stress and pore pressure distributions around boreholes under infinite/finite boundary conditions. Prospective applications include investigating the effect of gradually changing pore pressure, modelling open‐hole cavity completions, and describing the phenomenon of wellbore collapse (bridging) during oil or gas blowouts. Copyright © 2004 John Wiley & Sons, Ltd.
Statistical analysis of friction sleeve length effects on soil classification
Authors: Saussus D. R. , Frost J. D. , DeJong J. T. 
Published: August 2004

AbstractThe cone penetration test (CPT) provides profiles of the tip resistance, sleeve friction, and pore water pressure encountered while penetrating the subsurface. These parameters are used either directly or indirectly to classify the soil types present and to obtain geotechnical design parameters. However, fundamental discrepancies exist in the manner by which these parameters are measured. This paper describes the results of a study that shows the sleeve friction measurement introduces unnecessary redundancy due to the length of the standard friction sleeve compared to the measurement increment. Further, the high sleeve length to measurement increment ratio results in filtering and smoothing of the friction data, thereby causing the variability of the friction between the soil and the cone sleeve to be underestimated. The importance of understanding the role of the sleeve length on measurements is demonstrated using synthetically generated friction profiles and estimating the profiles that would be measured using sleeves of different lengths. Differences in how the soils are classified as a function of the sleeve length used to obtain each profile are illustrated. Solutions are presented to validate the synthetic sleeve friction profiles, to demonstrate the filtering and smoothing effects of the friction sleeve on the data, and to explain the implications of the sleeve length on soil classification. Copyright © 2004 John Wiley & Sons, Ltd.
A search game on a cyclic graph
Authors: Kikuta Kensaku 
Published: August 2004

AbstractThere is a finite cyclic graph. The hider chooses one of all nodes except the specified one, and he hides an (immobile) object there. At the beginning the seeker is at the specified node. After the seeker chooses an ordering of the nodes except the specified one, he examines each nodes in that order until he finds the object, traveling along edges. It costs an amount when he moves from a node to an adjacent one and also when he checks a node. While the hider wishes to maximize the sum of the traveling costs and the examination costs which are required to find the object, the seeker wishes to minimize it. The problem is modeled as a two‐person zero‐sum game. We solve the game when unit costs (traveling cost + examination cost) have geometrical relations depending on nodes. Then we give properties of optimal strategies of both players. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Embedding of cycles and wheels into arbitrary trees
Authors: Rajasingh Indra , William Albert , Quadras Jasintha , Manuel Paul 
Published: August 2004

AbstractWe estimate and characterize the edge congestion‐sum measure for embeddings of various graphs such as cycles, wheels, and generalized wheels into arbitrary trees. All embedding algorithms apply an interesting general technique based on the consecutive label property. Our algorithms produce optimal values of sum of dilations and sum of edge‐congestions in linear time. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(3), 173–178 2004
Optimal grid representations
Authors: Fampa M. H. C. , Klein S. , Protti F. , Rêgo D. C. A. 
Published: August 2004

AbstractA graph G is a grid intersection graph if G is the intersection graph of ℋ︁ ∪ ℐ, where ℋ︁ and ℐ are, respectively, finite families of horizontal and vertical linear segments in the plane such that no two parallel segments intersect. (This definition implies that every grid intersection graph is bipartite.) The family ℋ︁ ∪ ℐ is a representation of G. As a consequence of a characterization of grid intersection graphs by Kratochvíl, we observe that when a bipartite graph G = (U ∪ W, E) with minimum degree at least two is a grid intersection graph, then there exists a normalized representation of G on the (r × s)‐grid for r = |U| and s = |W|, that is, a representation in which all end points of segments have integer‐valued coordinates belonging to {(x, y) ∈ N × N | 1 ≤ y ≤ r, 1 ≤ x ≤ s} and the representative segment of each vertex lies on a distinct horizontal or vertical line. A natural problem, with potential applications to circuit layout, is the following: among all the possible normalized representations of G, find a representation ℛ such that the sum of the lengths of the segments in ℛ is minimum. In this work we introduce this problem and present a mixed integer programming formulation to solve it. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(3), 187–193 2004
Brief alteration in dopaminergic function during development causes deficits in adult reproductive behavior
Authors: Harding Cheryl F. 
Published: August 2004

AbstractOur previous research revealed dramatic increases in dopaminergic function in vocal control and auditory nuclei in male zebra finches during the period of song learning. Such increases were not seen in the hypothalamic areas examined. In the current study, we manipulated dopamine receptor function during this period to determine how this might affect later singing behavior. Males were implanted with osmotic minipumps providing 0, 0.5, or 5 μg/g/day of the mixed D1/D2 dopamine receptor antagonist cis‐flupenthixol from day 45 until day 57. At approximately 86 days of age, males were given subcutaneous silastic implants containing a maintenance dose of androgen, in case antagonist treatment interfered with adult androgen secretion. One week later, they began a series of three weekly tests to determine if this early treatment affected courtship singing. Males treated with the low dose of cis‐flupenthixol showed profound decrements in courtship singing and copulatory behavior. Unlike saline‐treated controls, low‐dose males sang to females infrequently. High‐intensity courtship displays in which males dance towards females while singing were most affected. Despite their decreased courtship singing, low‐dose males were interested in females. They approached females as frequently as males in the other two groups, but antagonist‐treated males were less likely to follow females if they moved. Low‐dose males also attempted to mount females significantly less often than high‐dose males. High‐dose males groomed significantly less frequently than males in the other two groups. Thus, brief early treatment with cis‐flupenthixol had profound and long‐lasting effects on female‐directed singing and on copulatory behavior, despite androgen treatment. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
Calcium‐induced calcium release contributes to somatic secretion of serotonin in leech Retzius neurons
Authors: Trueta Citlali , Sánchez‐Armass Sergio , Morales Miguel A. , De‐Miguel Francisco F. 
Published: August 2004

AbstractWe analyzed the contribution of calcium (Ca2+)‐induced Ca2+ release to somatic secretion in serotonergic Retzius neurons of the leech. Somatic secretion was studied by the incorporation of fluorescent dye FM1‐43 upon electrical stimulation with trains of 10 impulses and by electron microscopy. Quantification of secretion with FM1‐43 was made in cultured neurons to improve optical resolution. Stimulation in the presence of FM1‐43 produced a frequency‐dependent number of fluorescent spots. While a 1‐Hz train produced 19.5 ± 5.0 spots/soma, a 10‐Hz train produced 146.7 ± 20.2 spots/soma. Incubation with caffeine (10 mM) to induce Ca2+ release from intracellular stores without electrical stimulation and external Ca2+, produced 168 ± 21.7 spots/soma. This staining was reduced by 49% if neurons were preincubated with the Ca2+‐ ATPase inhibitor thapsigargin (200 nM). Moreover, in neurons stimulated at 10 Hz in the presence of ryanodine (100 μM) to block Ca2+‐induced Ca2+ release, FM1‐43 staining was reduced by 42%. In electron micrographs of neurons at rest or stimulated at 1 Hz in the ganglion, endoplasmic reticulum lay between clusters of dense core vesicles and the plasma membrane. In contrast, in neurons stimulated at 20 Hz, the vesicle clusters were apposed to the plasma membrane and flanked by the endoplasmic reticulum. These results suggest that Ca2+‐induced Ca2+ release produces vesicle mobilization and fusion in the soma of Retzius neurons, and supports the idea that neuronal somatic secretion shares common mechanisms with secretion by excitable endocrine cells. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
Serine proteases in the spiny lobster olfactory organ: Their functional expression along a developmental axis, and the contribution of a CUB‐serine protease
Authors: Johns Malcolm E. , Tai Phang C. , Derby Charles D. 
Published: August 2004

AbstractSeveral serine proteases and protease inhibitors have been identified in the crustacean olfactory organ, which is comprised of the lateral flagellum of the antennule and its aesthetascs sensilla that house olfactory receptor neurons and their supporting cells. The function of these proteases in the olfactory organ is unknown, but may include a role in perireception (e.g., odor activation or inactivation) or in the development or survival of olfactory receptor neurons. To examine directly the function of proteases in the olfactory organ of the Caribbean spiny lobster Panulirus argus, we used different tissue fractions from the lateral flagellum in an enzyme activity assay with a variety of protease substrates and inhibitors. Trypsin‐like serine protease activity occurs throughout the lateral flagellum but is enriched in the cell membranes from aesthetascs. Cysteine‐ and metalloprotease activities also occur in olfactory tissue, but are more abundant in tissue fractions other than aesthetascs. To assess the contribution of one of the olfactory serine proteases—CUB‐serine protease (Csp)—Csp was immunoprecipitated using an antibody; results with the remaining fraction suggest that Csp accounts for at least 40% of the total serine protease activity in the olfactory organ. The amount of total serine protease activity follows a developmental axis in the lateral flagellum. Total protease activity is lowest in the proximal zone, which lacks aesthetascs, and the proliferation zone, where olfactory receptor neurons and associated cells are born, and highest in aesthetascs of the distally‐located senescence zone, which has the oldest olfactory tissue. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
Partial muting leads to age‐dependent modification of motor patterns underlying crystallized zebra finch song
Authors: Cooper Brenton G. , Goller Franz 
Published: August 2004

AbstractThe crystallized structure of adult zebra finch (Taeniopygia guttata) song is modifiable if sensory feedback is altered during sound production. Such song plasticity has been studied by examining acoustic modifications to the motif; however, the underlying changes to the vocal motor patterns of these acoustic modifications have not been addressed. Adult birds in two age categories (young = 90–120 days or middle aged 150–250 days) that sang crystallized song were used in the experiment. Vocal motor patterns were monitored by recording respiratory air sac pressure before, during, and after song plasticity was induced by partial or complete reduction of phonation (i.e., “partial muting”). Birds were recorded until changes in air sac pressure patterns underlying the song structure were observed (up to 160 days). Young adult birds were more likely to insert shorter duration (<125 ms) expiratory pulses (EPs) into the motif than middle‐aged adults. These shorter duration EPs were produced with a unique pressure pattern relative to the intact song, and therefore appeared to be generated by novel motor gestures. Stuttering (atypical repetition of an EP) was observed when these novel EPs were inserted into the motif, regardless of age. The EP of the distance call, which is also a learned vocalization in zebra finches, showed a similar reduction in duration if EPs were also shortened in the song. The emergence of shorter duration EPs was not related to sound production, or nonspecific effects of the surgical procedure, which suggests an age‐dependent neural process for song plasticity. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
Two antagonistic gustatory receptor neurons responding to sweet‐salty and bitter taste in Drosophila
Authors: Hiroi Makoto , Meunier Nicolas , Marion‐Poll Frédéric , Tanimura Teiichi 
Published: August 2004

AbstractIn Drosophila, gustatory receptor neurons (GRNs) occur within hair‐like structures called sensilla. Most taste sensilla house four GRNs, which have been named according to their preferred sensitivity to basic stimuli: water (W cell), sugars (S cell), salt at low concentration (L1 cell), and salt at high concentration (L2 cell). Labellar taste sensilla are classified into three types, l‐, s‐, and i‐type, according to their length and location. Of these, l‐ and s‐type labellar sensilla possess these four cells, but most i‐type sensilla house only two GRNs. In i‐type sensilla, we demonstrate here that the first GRN responds to sugar and to low concentrations of salt (10–50 mM NaCl). The second GRN detects a range of bitter compounds, among which strychnine is the most potent; and also to salt at high concentrations (over 400 mM NaCl). Neither type of GRN responds to water. The detection of feeding stimulants in i‐type sensilla appears to be performed by one GRN with the combined properties of S + L1 cells, while the other GRN detects feeding inhibitors in a similar manner to bitter‐sensitive L2 cells on the legs. These sensilla thus house two GRNs having an antagonistic effect on behavior, suggesting that the expression of taste receptors is segregated across them accordingly. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
On the design of energy–momentum integration schemes for arbitrary continuum formulations. Applications to classical and chaotic motion of shells
Authors: Sansour Carlo , Wriggers Peter , Sansour Jamal 
Published: August 2004

AbstractThe construction of energy–momentum methods depends heavily on three kinds of non‐linearities: (1) the geometric (non‐linearity of the strain–displacement relation), (2) the material (non‐linearity of the elastic constitutive law), and (3) the one exhibited in displacement‐dependent loading. In previous works, the authors have developed a general method which is valid for any kind of geometric non‐linearity. In this paper, we extend the method and combine it with a treatment of material non‐linearity as well as that exhibited in force terms.In addition, the dynamical formulation is presented in a general finite element framework where enhanced strains are incorporated as well. The non‐linearity of the constitutive law necessitates a new treatment of the enhanced strains in order to retain the energy conservation property.Use is made of the logarithmic strain tensor which allows for a highly non‐linear material law, while preserving the advantage of considering non‐linear vibrations of classical metallic structures. Various examples and applications to classical and non‐classical vibrations and non‐linear motion of shells are presented, including (1) chaotic motion of arches, cylinders and caps using a linear constitutive law and (2) large overall motion and non‐linear vibration of shells using non‐linear constitutive law. Copyright © 2004 John Wiley & Sons, Ltd.