bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proinflammatory cytokine synthesis in the injured mouse spinal cord: Multiphasic expression pattern and identification of the cell types involved
Authors: Pineau Isabelle , Lacroix Steve 
Published: November 2006

AbstractWe have studied the spatial and temporal distribution of six proinflammatory cytokines and identified their cellular source in a clinically relevant model of spinal cord injury (SCI). Our findings show that interleukin‐1β (IL‐1β) and tumor necrosis factor (TNF) are rapidly (<5 and 15 minutes, respectively) and transiently expressed in mice following contusion. At 30–45 minutes post SCI, IL‐1β and TNF‐positive cells could already be seen over the entire spinal cord segment analyzed. Multilabeling analyses revealed that microglia and astrocytes were the two major sources of IL‐1β and TNF at these times, suggesting a role for these cytokines in gliosis. Results obtained from SCI mice previously transplanted with green fluorescent protein (GFP)‐expressing hematopoietic stem cells confirmed that neural cells were responsible for the production of IL‐1β and TNF for time points preceding 3 hours. From 3 hours up to 24 hours, IL‐1β, TNF, IL‐6, and leukemia inhibitory factor (LIF) were strongly upregulated within and immediately around the contused area. Colocalization studies revealed that all populations of central nervous system resident cells, including neurons, synthesized cytokines between 3 and 24 hours post SCI. However, work done with SCI‐GFP chimeric mice revealed that at least some infiltrating leukocytes were responsible for cytokine production from 12 hours on. By 2 days post‐SCI, mRNA signal for all the above cytokines had nearly disappeared. Notably, we also observed another wave of expression for IL‐1β and TNF at 14 days. Overall, these results indicate that following SCI, all classes of neural cells initially contribute to the organization of inflammation, whereas recruited immune cells mostly contribute to its maintenance at later time points. J. Comp. Neurol. 500:267–285, 2007. © 2006 Wiley‐Liss, Inc.
Magnetic resonance imaging and histological studies of corpus callosal and hippocampal abnormalities linked to doublecortin deficiency
Authors: Kappeler Caroline , Dhenain Marc , Phan Dinh Tuy Françoise , Saillour Yoann , Marty Serge , Fallet‐Bianco Catherine , Souville Isabelle , Souil Evelyne , Pinard Jean‐Marc , Meyer Gundela , Encha‐Razavi Ferechté , Volk Andreas , Beldjord Cherif , Chelly Jamel , Francis Fiona 
Published: November 2006

AbstractMutated doublecortin (DCX) gives rise to severe abnormalities in human cortical development. Adult Dcx knockout mice show no major neocortical defects but do have a disorganized hippocampus. We report here the developmental basis of these hippocampal abnormalities. A heterotopic band of neurons was identified starting at E17.5 in the CA3 region and progressing throughout the CA1 region by E18.5. At neonatal stages, the CA1 heterotopic band was reduced, but the CA3 band remained unchanged, continuing into adulthood. Thus, in mouse, migration of CA3 neurons is arrested during development, whereas CA1 cell migration is retarded. On the Sv129Pas background, magnetic resonance imaging (MRI) also suggested abnormal dorsal hippocampal morphology, displaced laterally and sometimes rostrally and associated with medial brain structure abnormalities. MRI and cryosectioning showed agenesis of the corpus callosum in Dcx knockout mice on this background and an intermediate, partial agenesis in heterozygote mice. Wild‐type littermates showed no callosal abnormalities. Hippocampal and corpus callosal abnormalities were also characterized in DCX‐mutated human patients. Severe hippocampal hypoplasia was identified along with variable corpus callosal defects ranging from total agenesis to an abnormally thick or thin callosum. Our data in the mouse, identifying roles for Dcx in hippocampal and corpus callosal development, might suggest intrinsic roles for human DCX in the development of these structures. J. Comp. Neurol. 500:239–254, 2007. © 2006 Wiley‐Liss, Inc.
Connections of functional areas in the mustached bat's auditory cortex with the auditory thalamus
Authors: Pearson James M. , Crocker William D. , Fitzpatrick Douglas C. 
Published: November 2006

AbstractThe auditory thalamus is the major target of the inferior colliculus and connects in turn with the auditory cortex. In the mustached bat, biosonar information is represented according to frequency in the central nucleus of the inferior colliculus (ICc) but according to response type in the cortex. In addition, the cortex has multiple areas with neurons of similar response type compared to the single tonotopic representation in the ICc. To investigate whether these transformations occur at the level of the thalamus, we injected anatomical tracers into physiologically defined locations in the mustached bat's auditory cortex. Injections in areas used for target ranging labeled contiguous regions of the auditory thalamus rather than separate patches corresponding to regions that respond to the different harmonic frequencies used for ranging. Injections in the two largest ranging areas produced labeling in separate locations. These results indicate that the thalamus is organized according to response type rather than frequency and that multiple mappings of response types exist. Injections in areas used for target detection labeled thalamic regions that were largely separate from those that interconnect with ranging areas. However, injections in an area used for determining target velocity overlapped with the areas connected to ranging areas and areas involved in target detection. Thus, separation by functional type and multiplication of areas with similar response type occurs by the thalamic level, but connections with the cortex segregate the functional types more completely than occurs in the thalamus. J. Comp. Neurol. 500:401–418, 2007. © 2006 Wiley‐Liss, Inc.
Spatial relationship between synapse loss and β‐amyloid deposition in Tg2576 mice
Authors: Dong Hongxin , Martin Maureen V. , Chambers Shawn , Csernansky John G. 
Published: November 2006

AbstractAlthough there is evidence that β‐amyloid impairs synaptic function, the relationship between β‐amyloid and synapse loss is not well understood. In this study we assessed synapse density within the hippocampus and the entorhinal cortex of Tg2576 mice at 6–18 months of age using stereological methods at both the light and electron microscope levels. Under light microscopy we failed to find overall decreases in the density of synaptophysin‐positive boutons in any brain areas selected, but bouton density was significantly decreased within 200 μm of compact β‐amyloid plaques in the outer molecular layer of the dentate gyrus and Layers II and III of the entorhinal cortex at 15–18 months of age in Tg 2576 mice. Under electron microscopy, we found overall decreases in synapse density in the outer molecular layer of the dentate gyrus at both 6–9 and 15–18 months of age, and in Layers II and III of the entorhinal cortex at 15–18 months of age in Tg 2576 mice. However, we did not find overall changes in synapse density in the stratum radiatum of the CA1 subfield. Furthermore, in the two former brain areas we found a correlation between lower synapse density and greater proximity to β‐amyloid plaques. These results provide the first quantitative morphological evidence at the ultrastructure level of a spatial relationship between β‐amyloid plaques and synapse loss within the hippocampus and the entorhinal cortex of Tg2576 mice. J. Comp. Neurol. 500:311–321, 2007. © 2006 Wiley‐Liss, Inc.
Parallel thalamocortical pathways for echolocation and passive sound localization in a gleaning bat, Antrozous pallidus
Authors: Razak Khaleel A. , Shen Weiming , Zumsteg Terese , Fuzessery Zoltan M. 
Published: November 2006

AbstractWe present evidence for parallel auditory thalamocortical pathways that serve two different behaviors. The pallid bat listens for prey‐generated noise (5–35 kHz) to localize prey, while reserving echolocation [downward frequency‐modulated (FM) sweeps, 60–30 kHz] for obstacle avoidance. Its auditory cortex contains a tonotopic map representing frequencies from 6 to 70 kHz. The high‐frequency (BF > 30 kHz) representation is dominated by FM sweep‐selective neurons, whereas most neurons tuned to lower frequencies prefer noise. Retrograde tracer injections into these physiologically distinct cortical regions revealed that the high‐frequency region receives input from the suprageniculate (SG) nucleus, but not the ventral division of the medial geniculate body (MGBv), in all experiments (n = 9). In contrast, the low‐frequency region receives tonotopically organized input from the MGBv in all experiments (n = 16). Labeling in the SG was observed in only two of these experiments. Both cortical regions also receive sparse inputs from medial (MGBm) and parts of the dorsal division (MGBd) outside the SG. These results show that the low‐ and high‐frequency regions of a single tonotopic map receive dominant inputs from different thalamic divisions. Within the low‐frequency region, most neurons are binaurally inhibited, and an orderly map of interaural intensity difference (IID) sensitivity is present. We show that the input to the IID map arises from topographically organized projections from the MGBv. As observed in other species, a frequency‐dependent organization is observed in the lateromedial direction in the MGBv. These data demonstrate that MGBv‐to‐auditory cortex connections are organized with respect to both frequency and binaural selectivity. J. Comp. Neurol. 500:322–338, 2007. © 2006 Wiley‐Liss, Inc.
Rod bipolar cells and horizontal cells form displaced synaptic contacts with rods in the outer nuclear layer of the nob2 retina
Authors: Bayley Philippa R. , Morgans Catherine W. 
Published: November 2006

AbstractThe nob2 mouse carries a null mutation in the Cacna1f gene, which encodes the pore‐forming subunit of the L‐type calcium channel, Cav1.4. The loss of the electroretinogram b‐wave in these mice suggests a severe reduction in transmission between photoreceptors and second‐order neurons in the retina and supports a central role for the Cav1.4 calcium channel at photoreceptor ribbon synapses, to which it has been localized. Here we show that the loss of Cav1.4 leads to the aberrant outgrowth of rod bipolar cell dendrites and horizontal cell processes into the outer nuclear layer (ONL) of the nob2 retina and to the formation of ectopic synaptic contacts with rod photoreceptors in the ONL. Ectopic contacts are predominantly between rods and rod bipolar cells, with horizontal cell processes also present at some sites. Ectopic contacts contain apposed pre‐ and postsynaptic specializations, albeit with malformed synaptic ribbons. Cone photoreceptor terminals do not participate in ectopic contacts in the ONL. During retinal development, ectopic contacts appear in the days after eye opening, appearing progressively farther into the ONL at later postnatal stages. Ectopic contacts develop at the tips of rod bipolar cell dendrites and are less frequently associated with the tips of horizontal cell processes, consistent with the adult phenotype. The relative occurrence of pre‐ and postsynaptic markers in the ONL during development suggests a mechanism for the formation of ectopic synaptic contacts that is driven by the retraction of rod photoreceptor terminals and neurite outgrowth by rod bipolar cell dendrites. J. Comp. Neurol. 500:286–298, 2007. © 2006 Wiley‐Liss, Inc.
Strategic expression of ion transport peptide gene products in central and peripheral neurons of insects
Authors: Dai Li , Zitnan Dusan , Adams Michael E. 
Published: November 2006

AbstractStructurally related ion transport peptides (ITP) and crustacean hyperglycemic hormones (CHH) are increasingly implicated in diverse metabolic and developmental functions in arthropods. We identified a conserved ITP gene encoding two peptides by alternative splicing in Manduca sexta, Bombyx mori, and Aedes aegypti: A C‐terminally amidated ITP and a C‐terminally unblocked ITP‐like peptide (ITPL), which share common N‐terminal sequences but have divergent C‐termini. In the moth M. sexta, these peptides are expressed in two, regionally distinct neuronal populations in the central and peripheral nervous systems (CNS, PNS). MasITP expression is confined to the brain in five pairs of lateral neurosecretory cells (type Ia2) projecting ipsilateral axons into the retrocerebral complex and three to five pairs of adjacent small neurons that arborize extensively within the brain. Expression of MasITPL is comparatively weak in the brain but strong in the ventral ganglia and the PNS, where MasITP is absent. MasITPL occurs in bilaterally paired neurons of all thoracic and abdominal ganglia. In the PNS, MasITPL is coexpressed with crustacean cardioactive peptide in type II link nerve neurons (L1) of abdominal segments 2–7, which project axons into neurohemal transverse nerves. During metamorphosis, additional expression of MasITPL is observed in two pairs of small lateral neurons in the brain and one pair of ventromedial neurons in each of AG2–6. A similar pattern of differential ITP and ITPL expression was observed in the CNS and PNS of B. mori and Schistocerca americana. These distinctive cellular expression patterns suggest that ITP and ITPL have evolved specialized physiological functions in arthropods. J. Comp. Neurol. 500:353–367, 2007. © 2006 Wiley‐Liss, Inc.
A locally discontinuous enriched finite element formulation for acoustics
Authors: Rochinha F. A. , Alvarez G. B. , do Carmo E. G. D. , Loula A. F. D. 
Published: November 2006

AbstractIn (Comput. Methods Appl. Mech. Eng. 2006, in press) we introduced a discontinuous Galerkin finite element method for Helmholtz equation in which continuity is relaxed locally in the interior of the element. The shape functions associated with interior nodes of the element are bilinear discontinuous bubbles, and the corresponding degrees of freedom can be eliminated at element level by static condensation yielding a global finite element method with the same connectivity of classical C0 Galerkin finite element approximations. Stability is provided by the discontinuous bubbles with appropriate choice of the stabilization parameters related to the weak enforcement of continuity inside each element. In the present work, departing from the stencil obtained by condensation of the bubble degrees of freedom, we build a new strategy for determining the optimal values of these parameters aiming at matching the exact wave number in two different directions. Stability and accuracy of the proposed formulation are demonstrated in several numerical examples. Copyright © 2006 John Wiley & Sons, Ltd.
Extension of weakly compressible approximations to incompressible thermal flows
Authors: El‐Amrani Mofdi , Seaïd Mohammed 
Published: November 2006

AbstractWeakly compressible and advection approximations of incompressible isothermal flows were developed and tested in (Commun. Numer. Methods Eng. 2006; 22:831–847). In this paper, we extend the method to solve equations governing incompressible thermal flows. The emphasis is again on the reconstruction of unconditionally stable numerical scheme such that, restriction on time steps, projection procedures, solution of linear system of algebraic equations and staggered grids are completely avoided in its implementation. These features are achieved by combining a low‐Mach asymptotic in compressible flow equations with a semi‐Lagrangian method for the weakly compressible approach. The time integration is carried out using an explicit Runge–Kutta with variable stages. The method is applied to the natural convection flows in a squared cavity for both steady and transient computations. The numerical results demonstrate high resolution of the proposed method and confirm its capability to provide accurate and efficient simulations for thermal flow problems. Copyright © 2006 John Wiley & Sons, Ltd.
Erratum: Yan Guo. Boltzmann diffusive limit beyond the Navier‐Stokes approximation, Communications on Pure and Applied Mathematics (2006) 59(5) 626‐687
Authors: Guo Yan 
Published: November 2006

AbstractThe original article to which this erratum refers was published in Communications on Pure and Applied MathematicsComm Pure Appl Math(2006)59(5) 626.
Multiprogramming a distributed‐memory multiprocessor
Authors: Leuze Michael R. , Dowdy Lawrence W. , Park Kee Hyun 
Published: November 2006

AbstractThe development of computing systems with large numbers of processors has been motivated primarily by the need to solve large, complex problems more quickly than is possible with uniprocessor systems. Traditionally, multiprocessor systems have been uniprogrammed, i.e., dedicated to the execution of a single set of related processes, since this approach provides the fastest response for an individual program once it begins execution. However, if the goal of a multiprocessor system is to minimize average response time or to maximize throughput, then multiprogramming must be considered.In this paper, a model of a simple multiprocessor system with a two‐program workload is reviewed; the model is then applied to an Intel iPSC/2 hypercube multiprocessor with a workload consisting of parallel wavefront algorithms for solving triangular systems of linear equations. Throughputs predicted by the model are compared with throughputs obtained experimentally from an actual system. The results provide validation for the model and indicate that significant performance improvements for multiprocessor systems are possible through multiprogramming.
Supersonic fluid flow in parallel with an unstructured mesh
Authors: Williams Roy D. 
Published: November 2006

AbstractAn algorithm has been implemented for time‐accurate solutions of the two‐dimensional compressible Euler equations using an irregular triangular mesh. The code runs on distributed or shared memory or sequential machines, and is written using the Distributed Irregular Mesh Environment (DIME). DIME is a programming environment for calculations with such meshes, with adaptive mesh refinement and dynamic load balancing. Results are presented for an example of a Mach 3 flow over a step, computed with a 32‐processor NCUBE hypercube.
A step‐wise‐overlapped parallel annealing algorithm on a message‐passing multiprocessor system
Authors: Kim Youngtak , Kim Myunghwan 
Published: November 2006

AbstractThis paper proposes a parallel annealing algorithm, called step‐wise‐overlapped parallel annealing, that can provide a massive speed‐up utilizing a multiprocessor system with a large number of processors. We improve the parallel annealing scheme of the systolic algorithm that was proposed by Aart et al. Instead of the temperature decrement at each subchain, it decides the decrement ratio at the start of each Markov chain using the standard deviation of the cost distribution in the previous Markov chain of the full length. Thus the improved annealing schedule keeps a good temperature profile even with a large number of processors. We also enhance the communication pattern.The new parallel annealing algorithm has a simple communication pattern and thus less communication overheads. The decomposition strategy of this parallel annealing algorithm is independent of application problems. Experimental results of the step‐wise‐overlapped parallel annealing algorthm for the travelling salesman problems show high efficiencies even when a large number of processors are used; it produces near optimal solutions with a speedup of 70.8 by using 128 processors. It can be implemented efficiently on a message‐passing multiprocessor system with a large number of processors, such as a hypercube computer.
Benchmarking advanced architecture computers
Authors: Messina P. , Felten E. , Hipes P. , Williams R. , Alagar A. , Kamrath A. , Leary R. , Pfeiffer W. , Rogers J. , Walker D. 
Published: November 2006

AbstractRecently, a number of advanced architecture machines have become commercially available. These new machines promise better cost performance than traditional computers, and some of them have the potential of competing with current supercomputers, such as the CRAY X‐MP, in terms of maximum performance. This paper describes the methodology and results of a pilot study of the performance of a broad range of advanced architecture computers using a number of complete scientific application programs. The computers evaluated include:

shared‐memory bus architecture machines such as the Alliant FX/8, the Encore Multimax, and the Sequent Balance and Symmetry
shared‐memory network‐connected machines such as the Butterfly
distributed‐memory machines such as the NCUBE, Intel and Jet Propulsion Laboratory (JPL)/Caltech hypercubes
very long instruction word machines such as the Cydrome Cydra‐5
SIMD machines such as the Connection Machine
‘traditional’ supercomputers such as the CRAY X‐MP, CRAY‐2 and SCS‐40.
Seven application codes from a number of scientific disciplines have been used in the study, although not all the codes were run on every machine. The methodology and guidelines for establishing a standard set of benchmark programs for advanced architecture computers are discussed. The CRAYs offer the best performance on the benchmark suite; the shared memory multiprocessor machines generally permitted some parallelism, and when coupled with substantial floating point capabilities (as in the Alliant FX/8 and Sequent Symmetry), provided an order of magnitude less speed than the CRAYs. Likewise, the early generation hypercubes studied here generally ran slower than the CRAYs, but permitted substantial parallelism from each of the application codes.
Performance of a benchmark parallel implementation of the Van Slyke and Wets algorithm for two‐stage stochastic programs on the Sequent/Balance
Authors: Ariyawansa K. A. , Hudson D. D. 
Published: November 2006

AbstractWe describe a benchmark parallel version of the Van Slyke and Wets (1969) algorithm for two‐stage stochastic programs and an implementation of that algorithm on the Sequent/Balance. We also report results of a numerical experiment using random test problems and our implementation. These performance results, to the best of our knowledge, are the first available for the Van Slyke and Wets (1969) algorithm on a parallel processor. They indicate that the benchmark implementation parallelizes well.
Cluster Identification Algorithms for Spin Models — Sequential and Parallel
Authors: Baillie Clive F. , Coddington Paul D. 
Published: November 2006

AbstractMonte Carlo cluster update algorithms are extremely efficient for simulating spin models near their phase transitions, where local update algorithms suffer severe critical slowing down. Unfortunately, as the cluster algorithms are highly irregular as well as nonlocal, they are much more difficult to parallelize efficiently. The main difficulty lies in identifying which spins belong to which cluster. In this paper we investigate a number of cluster identification algorithms, both sequential and parallel, which we have implemented on serial, SIMD and MIMD computers.
‘Blade Runner’: A real‐time speech recognizer
Authors: Chong Mike , Fallside Frank , Marsland Tim , Prager Richard 
Published: November 2006

AbstractA real‐time prototype speech recognizer has been implemented on a 66‐processor distributed‐memory parallel computer. Simple phrases are recognized in approximately 4 to 10 seconds. Scalability, performance and flexibility are the three main aims of this implementation, the ultimate goal being to construct a large vocabulary speech recognizer which responds quickly. A set of three techniques is investigated in this implementation: asynchronous methodology to minimize synchronization overheads, distributed control to avoid a central communications bottleneck, and dynamic load balancing to provide a flexible response to an unpredictable computational load. The effect on memory, processor time allocation and communications is observed in real‐time using hardware monitoring aids.