bluuebunny/crossref_metadata_2025_split huggingface dataset:
MRI to detect atherosclerosis with gadolinium‐containing immunomicelles targeting the macrophage scavenger receptor
Authors: Lipinski Michael J. , Amirbekian Vardan , Frias Juan C. , Aguinaldo Juan Gilberto S. , Mani Venkatesh , Briley‐Saebo Karen C. , Fuster Valentin , Fallon John T. , Fisher Edward A. , Fayad Zahi A. 
Published: August 2006

AbstractThe ability to specifically image macrophages may enable improved detection and characterization of atherosclerosis. In this study we evaluated the in vitro uptake of gadolinium (Gd)‐containing immunomicelles (micelles linked to macrophage‐specific antibody), micelles, and standard contrast agents by murine macrophages, and sought to determine whether immunomicelles and micelles improve ex vivo imaging of apolipoprotein E knockout (ApoE KO) murine atherosclerosis. Murine RAW 264.7 macrophages were incubated with Gd‐DTPA, micelles, and immunomicelles. Cell pellets were prepared and imaged using a 1.5 T MR system with an inversion recovery spin‐echo sequence to determine the in vitro T1 values. Ex vivo analysis of mouse aortas was performed using a 9.4T MR system with a high‐spatial‐resolution sequence (78 × 39 × 78 μm3). The T1 value was significantly decreased in cells treated with micelles compared to Gd‐DTPA (P < 0.0001), and in cells incubated at 4°C with immunomicelles compared to micelles (P < 0.05). Ex vivo MRI signal intensity (SI) was significantly increased by 81% and 20% in aortas incubated with immunomicelles and micelles, respectively. Confocal microscopy demonstrated in vitro and ex vivo uptake of fluorescent immunomicelles by macrophages. Immunomicelles and micelles improve in vitro and ex vivo MR detection of macrophages, and may prove useful in the detection of macrophage‐rich plaques. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Three‐dimensional magnetic resonance microscopy of pulmonary solitary tumors in transgenic mice
Authors: Kubo Shigeto , Levantini Elena , Kobayashi Susumu , Kocher Olivier , Halmos Balazs , Tenen Daniel G. , Takahashi Masaya 
Published: August 2006

AbstractWe attempted to accurately detect pulmonary solitary tumors and other complicated pulmonary disorders in aging inbred transgenic mice by cardiac‐ and respiratory‐gated MR microscopy at 4.7 Tesla. A comparison of in vivo MR images with histological results demonstrated that submillimeter lung tumors and most of the nontumor lesions could be detected by screening with two‐dimensional (2D) gradient echo (GRE) imaging. Subsequently performed 2D spin‐echo (SE) imaging provided higher image contrast, which distinguished the tumors from the surrounding complications. On the 3D GRE images and the generated maximum intensity projection (MIP) and volume‐rendered (VR) images, proper spatial localization of solitary tumors relative to the orientation of the pulmonary vessels was exhibited, and the tumor volume could also be measured. This promising method is noninvasive and has the potential to eventually replace invasive histopathology because it obviates the need to kill groups of animals at multiple time points. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Primary role of the serotonergic midline system in synchronized spontaneous activity during development of the embryonic mouse hindbrain
Authors: Hunt P.N. , Gust J. , McCabe A.K. , Bosma M.M. 
Published: August 2006

AbstractIn the developing embryonic mouse hindbrain, we have shown that previously widespread synchronized spontaneous activity at E11.5 retracts to the initiating zone of the rostral hindbrain by E13.5, and ceases completely by E14.5. We now confirm that at E11.5 and E13.5, the primary driver of spontaneous activity is serotonergic input, while other transmitters (GABA, glutamate, NE, and ATP) have only modulatory roles. Using immunocytochemistry, we also show that at E13.5, 5‐HT‐positive neurons in the midline extend over a larger rostro‐caudal distance than at E11.5, and that in the presumptive initiating zone, cell bodies occupy a band that extends 200 μm laterally on each side of the midline, with extensive axonal processes. The 5‐HT2A receptor retains expression in lateral tissue over this developmental time. We find that in addition to being sensitive to 5‐HT receptor antagonists, spontaneous activity is also abolished by blockers of gap junctions, and is increased in frequency and lateral spread by application of ammonium, presumably via increased intracellular pH augmenting gap junction conductance. Thus, 5‐HT neurons of the midline remain the primary drivers of spontaneous activity at several stages of development in the hindbrain, relying in part on gap junctional communication during initiation of activity. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1239–1252, 2006
Spatial restriction of spontaneous activity towards the rostral primary initiating zone during development of the embryonic mouse hindbrain
Authors: Hunt P.N. , McCabe A.K. , Gust J. , Bosma M.M. 
Published: August 2006

AbstractIn the developing embryonic mouse hindbrain, we have previously shown that synchronized spontaneous activity is driven by midline serotonergic neurons at E11.5. This is mediated, at least in part, by the 5‐HT2A receptor, which is expressed laterally in the hindbrain. Activity at E11.5 is widespread within the hindbrain tissue, propagating from the midline to more lateral regions. Using rapid acquisition of [Ca2+]i events along the midline, we now show that the rostral midline, primarily in the region of former rhombomere r2, is the primary initiating zone for this activity. We propose that at E11.5, the combined events along the rostral‐caudal axis in combination with events propagating along the medial‐lateral axis could assign positional information to developing neurons within the hindbrain. With further development, to E13.5, both the lateral and caudal dimensions of spontaneous activity retract to the rostral midline, occupying an area only 14% of that exhibited at E11.5. We also show that increased levels of [K+]o (to 8 mM) at E13.5 are able to increase the spread of spontaneous activity laterally and rostro‐caudally. This suggests that spontaneous activity in the hindbrain depends in a dynamic way on the dominant initiating zone of the rostral midline, and that this relationship changes over development. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1225–1238, 2006
Intersegmental transfer of sensory signals in the stick insect leg muscle control system
Authors: Stein Wolfgang , Büschges Ansgar , Bässler Ulrich 
Published: August 2006

AbstractIntersegmental coordination during locomotion in legged animals arises from mechanical couplings and the exchange of neuronal information between legs. Here, the information flow from a single leg sense organ of the stick insect Cuniculina impigra onto motoneurons and interneurons of other legs was investigated. The femoral chordotonal organ (fCO) of the right middle leg, which measures posture and movement of the femur‐tibia joint, was stimulated, and the responses of the tibial motoneuron pools of the other legs were recorded. In resting animals, fCO signals did not affect motoneuronal activity in neighboring legs. When the locomotor system was activated and antagonistic motoneurons were bursting in alternation, fCO stimuli facilitated transitions from flexor to extensor activity and vice versa in the contralateral leg. Following pharmacological treatment with picrotoxin, a blocker of GABA‐ergic inhibition, the tibial motoneurons of all legs showed specific responses to signals from the middle leg fCO. For the contralateral middle leg we show that fCO signals encoding velocity and position of the tibia were processed by those identified local premotor nonspiking interneurons known to contribute to posture and movement control during standing and voluntary leg movements. Interneurons received both excitatory and inhibitory inputs, so that the response of some interneurons supported the motoneuronal output, while others opposed it. Our results demonstrate that sensory information from the fCO specifically affects the motoneuronal activity of other legs and that the layer of premotor nonspiking interneurons is a site of interaction between local proprioceptive sensory signals and proprioceptive signals from other legs. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1253–1269, 2006
A posteriori error estimator for expanded mixed hybrid methods
Authors: Kim Dongho , Park Eun‐Jae 
Published: August 2006

AbstractIn this article, we construct an a posteriori error estimator for expanded mixed hybrid finite‐element methods for second‐order elliptic problems. An a posteriori error analysis yields reliable and efficient estimate based on residuals. Several numerical examples are presented to show the effectivity of our error indicators. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 23: 330–349, 2007
A SAXS study of the structure of gels formed by mixtures of polyoxyalkylene triblock copolymers
Authors: Hamley Ian W , Castelletto Valeria , Ricardo Nágila MPS , Pinho Maria EN , Booth Colin , Attwood David , Yang Zhuo 
Published: August 2006

AbstractSmall‐angle X‐ray scattering was used to characterise aqueous micellar gels of triblock copolymers E137S18E137, E82S9E82, E76S5E76, E62P39E62, and of two mixtures: E137S18E137 and E62P39E62 (Mix 1) and E82S9E82 and E62P39E62 (Mix 2), each 50/50 wt%. E = oxyethylene, CH2CH2O; S = oxyphenylethylene, OCH2CH(C6H5); and P = oxypropylene, OCH2CH(CH3). Within the concentration and temperature ranges investigated (30–40 wt% copolymer, 20–80 °C), spherical micelles of copolymers E137S18E137, E82S9E82 and E62P39E62 packed into body‐centred cubic (BCC) structures. Gels of E76S5E76 were stable only at high concentrations and low temperatures, and a 70 wt% copolymer solution at T = 30 °C formed a hexagonal gel consistent with cylindrical micelles. It is likely that the mixed copolymers would form two distributions of micelles, and more complex structures were expected. However, gels of Mix 2 had well‐ordered BCC structures, while the less ordered gels of Mix 1 were also best characterised as BCC. Copyright © 2006 Society of Chemical Industry
Modeling non‐equilibrium morphologies in specific polymeric materials
Authors: Welch P. M. , Rasmussen K. Ø. , Chitanvis S. M. , Lookman T. , Sewell T. D. 
Published: August 2006

AbstractWe provide a numerical scheme for determining the Ginzburg–Landau free energy density directly from analysis of real or simulated images of phase evolving polymers. Our technique is robust and rapidly converges without requiring that the system reach equilibrium. The coefficients for the functional thus obtained agree with well‐known mean‐field trends. To our knowledge, this is the first prescription for specifying both the magnitudes and temperature dependencies for all of the free energy coefficients from microscopic models. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2605–2611, 2006
Weak polyelectrolytes tethered to surfaces: Effect of geometry, acid–base equilibrium and electrical permittivity
Authors: Nap Rikkert , Gong Peng , Szleifer Igal 
Published: August 2006

AbstractThe structural and thermodynamical properties of weak polyelectrolytes end‐tethered to surfaces of arbitrary geometry are studied using a molecular theory. The theory is based on writing down the free energy functional of the system including all the basic interactions and the explicit acid–base equilibrium for the chargeable groups of the polymer. The theory explicitly includes the size, shape, conformations, and charge distribution of all the molecular species. The electrostatic interactions include a density‐dependent dielectric function, modeled with the Maxwell–Garnett mixing formula, to account for the composition‐dependent permittivity. The minimization of the free energy leads to the distribution of all molecular species and their dependence on bulk pH and salt concentration. We apply the theory to polymer chains end‐tethered to planar, cylindrical, and spherical surfaces. The radius of the curved surfaces is small to enhance the curvature effect. We find that when the grafting surfaces are uncharged, the approximation of a constant dielectric function works very well for both structural and thermodynamic properties. The structure of weak polyelectrolytes tethered on cylindrical and spherical surfaces is different from that of polymers tethered on planar surfaces due to the available volume as a function of the distance from the surface. Specifically, the degree of dissociation increases with increasing curvature of the surface. This is a manifestation of the coupling between the local density of protons, counterions, and polymer segments. The results can be interpreted in terms of the local Le Chatelier principle for the acid–base equilibrium, with proper account of the three local contributions: counterions, protons, and chargeable groups. We find that one can achieve local changes of pH between one to two units within 1–2 nm. The thickness of the tethered layers as a function of bulk pH shows a large increase when the pH is equal to the bulk pK. However, the variation with salt concentration is different for the different geometries. The largest swelling is found for cylindrical surfaces. The predictions from scaling theories of a maximum in the thickness of the film as a function of salt concentration is found for planar films, but not for curved surfaces. Finally, the interactions between cylinders with tethered polyelectrolytes is very different from the equivalent planar surfaces. These results are important for the interpretation of force measurements with nanoscale AFM tips. The implications of the results for the rational design of responsive tethered polymer layers is discussed together with the limitations of the theoretical approach. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2638–2662, 2006
Two tube models of rubber elasticity
Authors: Vandoolaeghe W. L. , Kutter S. , Terentjev E. M. 
Published: August 2006

AbstractPolymer entanglements lead to complicated topological constraints and interactions between neighboring chains in a dense solution or melt. Entanglements can be treated in a mean field approach, within the famous reptation model, since they effectively confine each individual chain in a tube‐like geometry. In polymer networks, due to crosslinks preventing the global reptation and constraint release, entanglements acquire a different topological meaning and have a much stronger effect on the resulting mechanical response. In this article we discuss two different models of rubber elasticity, both utilizing the reptation ideas. First, we apply the classical ideas of reptation statistics to calculate the effective rubber‐elastic free energy of an entangled rubbery network. In the second approach, we examine the classical Rouse dynamics of chains with quenched constraints at their ends by crosslinks, and along the primitive path by entanglements. We then proceed to average amicroscopicstress tensor for the network system and present it in a manageable form in the equilibriumt→ ∞ limit. Particular attention is paid to the treatment of compressibility and hydrostatic pressure in a sample with open boundaries. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2679–2697, 2006
Free volume and stochastic theory of volume relaxation
Authors: Simha Robert , Roberston Richard E. 
Published: August 2006

AbstractThe stochastic theory of volume relaxation previously applied to the physical aging process in the glassy state of polymers had been formulated as a discrete set of coupled differential equations for the time‐dependent, discrete free volume state probabilities. A reformulation of this theory for a continuum of free volume states is described in the present article. The result is a Schrödinger‐like equation, which has the advantage of an extensive availability of numerical procedures for its solution under various conditions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2663–2666, 2006
Dynamics of polyethylene melts studied by Monte Carlo simulations on a high coordination lattice
Authors: Lin Heng , Mattice Wayne L. , Von Meerwall Ernst D. 
Published: August 2006

AbstractA detailed comparison is made between the experiment, prior simulations by other groups, and our simulation based on a newly designed dynamic Monte Carlo algorithm, on the dynamics of polyethylene (PE) melts. The new algorithm, namely, noncross random two‐bead move has been developed on a high coordination lattice (the 2nnd lattice) for studying the dynamics of realistic polymers. The chain length (molecular weight) in our simulation ranges from C40 (562 Da) to C324 (4538 Da). The effects of finite chain length have been confirmed and significant non‐Gaussian statistics evidently results in nonstandard static and dynamic properties of short PE chains. The diffusion coefficients scale with molecular weight (M) to the −1.7 power for short chains and −2.2 for longer chains, which coincides very well with experimental results. No pure Rouse scaling in diffusion has been observed. The transitional molecular weight to the entanglement regime is around 1500 Da. The detailed mean square displacements of middle bead (g1) are presented for several chain lengths. The reptation‐like slowdown can be clearly observed only above M ∼ 2400 Da. The slope 0.25 predicted by the theory for the intermediate regime is missing; instead a slope close to 0.4 appears, indicating that additional relaxation mechanism exists in this transitional region. The relaxation times extracted by fitting the autocorrelation function of end‐to‐end vectors with reptation model scale with M to 2.5 for long chains, which seemingly conflicts with the scaling of diffusion. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2556–2571, 2006
Molecular characterization of the two‐component histidine kinase gene from Monilinia fructicola
Authors: Ma Zhonghua , Luo Yong , Michailides Themis 
Published: August 2006

AbstractBrown rot of stone fruit caused by Monilinia fructicola (G. Wint) Honey is one of the most common fungal diseases in California. In this study, two laboratory‐induced iprodione‐resistant (LIR) mutants of M. fructicola were characterized by osmotic sensitivity, virulence on prune and sequence of the two‐component histidine kinase gene (Mfos‐1). The LIR mutants showed more sensitivity to osmotic stress and lower virulence on prune than their wild‐type parent. Analysis of deduced amino acid of Mfos‐1 showed that this protein exhibited all the characteristic features of the two‐component histidine kinase genes, including osmotic sensing domain, six 90‐amino‐acid repeat motifs (coiled coil region) and kinase core and response regulator domains. Comparison of DNA sequences of the Mfos‐1 from LIR mutants and the wild‐type sensitive (S) isolate showed that LIR mutants had single point mutations in the coiled coil region of Mfos‐1. Copyright © 2006 Society of Chemical Industry
An in vitro screening assay to discover novel inhibitors of 4‐coumarate:CoA ligase
Authors: Yun Min‐Soo , Chen Weijun , Deng Fan , Kiyokawa Takahiro , Mametsuka Koki , Yogo Yasuhiro 
Published: August 2006

Abstract4‐Coumarate:CoA ligase (4CL, EC 6.2.1.12) exists only in plants and plays an important role in the phenylpropanoid pathway. Identification of inhibitors targeting 4CL provides a novel approach for developing effective plant growth inhibitors (PGIs). The full‐length gene of tobacco 4CL (Nt4CL1) was cloned and expressed in Escherichia coli Cast & Chalm. The recombinant 4CL protein was extracted and purified by several purification steps including gel‐filtration and anion‐exchange chromatography. 4CL activity assay was miniaturized and optimized using a 96‐well microplate and a reader. Among 28 existing herbicides, propanil and swep strongly inhibited in vitro 4CL enzyme activity, and they were selected for further studies. The process of this assay can be developed into a high‐throughput screening system of PGI targeting 4CL in the phenylpropanoid pathway. Copyright © 2006 Society of Chemical Industry
Thickness scaling of space‐charge‐limited currents in organic layers with field‐ or density‐dependent mobility
Authors: Bisquert Juan , Montero José M. , Bolink Henk J. , Barea Eva M. , Garcia‐Belmonte Germà 
Published: August 2006

AbstractAn exact solution is provided for the current density‐voltage (J –V) characteristics of space‐charge limited transport of a single carrier in organic layers with field‐dependent mobility of the type μ (E) = μ 0 exp (γ √E. The general scaling relationship for field‐dependent mobility occurs in terms of the variables JL and V /L. For the density‐dependence of the mobility found in organic field‐effect transistor measurements, the thickness scaling occurs in terms of different variables, J 1/β L and V /L. The proposed scaling is a useful test for distinguishing field‐ and carrier density‐dependent mobility in disordered organic semiconductors. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effectiveness of tibolone on the reduction of menopausal problems—a Bayesian semi‐parametric interpretation
Authors: Das Kalyan , Naskar Malay 
Published: August 2006

AbstractTwo major physiological problems women experience at the time of menopause are hot flush and vaginal dryness. Exploratory investigations reveal that these two binary outcomes are very much dependent as both of them have predominant oestrogenic effects. A primary interest is to investigate how the bivariate association and the marginal univariate risks are affected by repeated measurements on each woman over several months. To achieve this we propose a very general class of bivariate binary models. Parametric inference is drawn on the basis of full non‐parametric Bayesian approach under Dirichlet process mixture. Study addresses some more interesting phenomena on the effectiveness of tibolone treatment in reducing menopausal problems. A simulation study further strengthens the proposed methodology. Copyright © 2006 John Wiley & Sons, Ltd.
Stochastically curtailed phase II clinical trials
Authors: Ayanlowo A. O. , Redden D. T. 
Published: August 2006

AbstractPhase II trials often test the null hypothesis H0: p ⩽ p0 versus H1: p ⩾p1, where p is the true unknown proportion responding to the new treatment, p0 is the greatest response proportion which is deemed clinically ineffective, and p1 is the smallest response proportion which is deemed clinically effective. In order to expose the fewest number of patients to an ineffective therapy, phase II clinical trials should terminate early when the trial fails to produce sufficient evidence of therapeutic activity (i.e. if p ⩽p0). Simultaneously, if a treatment is highly effective (i.e. if p⩾p1), the trial should declare the drug effective in the fewest patients possible to allow for advancement to a phase III comparative trial. Several statistical designs, including Simon's minimax and optimal designs, have been developed that meet these requirements. In this paper, we propose three alternative designs that rely upon stochastic curtailment based on conditional power. We compare and contrast the properties of the three approaches: (1) stochastically curtailed (SC) binomial tests, (2) stochastically curtailed (SC) Simon's optimal design, and (3) SC Simon's minimax design to those of Simon's minimax and Simon's optimal designs. For each of these designs we compare and contrast the number of opportunities for study termination, the expected sample size of the trial under the null hypothesis (p ⩽p0), and the effective type I and type II errors. We also present graphical tools for monitoring phase II clinical trials with stochastic curtailment using conditional power. Copyright © 2006 John Wiley & Sons, Ltd.