bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Set, High-Early Strength, Non-Excavatable Flowable Fill
Authors: Crouch LK , James Dotson V , Clouse L , Egan B , Hall SM
Published: October 2004

A high-flow, rapid-set, non-excavatable CLSM mixture called ZOOM was developed for applications where time was critical using normal concrete component materials. The following criteria were established for the ZOOM mixture:

• Pass the ASTM D 6024 in 6 h or less regardless of subgrade moisture conditions

• Little or no bleeding or shrinkage

• Flow as per ASTM D 6103 greater than 222 mm

• Greater than 207 kPa compressive strength as per ASTM D 4832 in 24 h

• Be able to perform using a wide variety of Tennessee aggregates

The development of the ZOOM mixture began in the laboratory in May 2002 using Ohio River Sand (ORS). Subsequently, the mixture proportions were adjusted to produce the desired plastic and hardened properties with other Tennessee fine aggregates. Three successful field demonstrations using different fine aggregates were held across Tennessee in the fall of 2002. ZOOM CLSM met compressive strength development and time of suitability for load application performance criteria at every field demonstration. Plastic properties were adequate but failed to meet the established criteria on two occasions. Fine aggregate properties such as gradation and angularity were found to dictate mixture proportions required to achieve flow, air content, and bleeding characteristics. Average air temperature and CLSM air content were found to be important to time of suitability for load application. The research effort was cosponsored by the Tennessee Department of Transportation and the Tennessee Ready Mixed Concrete Association
Methods for Field and Laboratory Measurement of Flowability and Setting Time of Controlled Low-Strength Materials
Authors: Tripathi H , Pierce CE , Gassman SL , Brown TW
Published: October 2004

Flow consistency and setting time are two important properties of controlled low-strength materials (CLSM). This paper describes and evaluates several standard and non-standard methods to measure these properties. Several mixtures with a range of water-to-binder ratios were investigated through a series of field and laboratory experiments. A linear relationship was observed between the flowability measured by the flow cylinder method (ASTM D 6103) and the inverted slump cone method. Pocket penetrometer and Torvane measurements were compared to the Kelly Ball method (ASTM D 6024) for estimating sufficient bearing capacity. Pocket penetrometer resistance correlates well, but its capacity was often exceeded. Volume stability should be controlled to avoid softening of the surface and subsequent delays in measured hardening time.
Thermally Insulating Foundations and Ground Slabs Using Highly-Foamed Concrete
Authors: Jones MR , Giannakou A
Published: October 2004

Foamed concrete, comprising a cementitious paste or mortar together with preformed foam, has many attractive properties, perhaps the most useful being its excellent thermal insulation properties, and therefore it can be classified as controlled thermal fill (CTF). Although widely used as a simple backfill, foamed concrete can be designed easily for particular densities (800–1600 kg/m3), flow characteristics (100–300 mm spread), strength (typically less than 10 MPa), and thermal insulation performance (0.2–0.6 W/mK). These properties make it an ideal material for house construction, in particular, for enhancing the thermal efficiency of the foundations and ground slab. This paper examines the performance of a range of foamed concretes for trench fill foundations and ground slabs in terms of thermal performance and main engineering, permeation, and durability properties. The consonant advantages of using fly ash (low-lime, fine, and coarse) technology will also be discussed.
Development of Non-Destructive Test Methods for Assessing Effects of Thermal Exposures on Fire Fighters' Turnout Gear
Authors: Thorpe PA , Torvi DA
Published: October 2004

The clothing that serves to protect a fire fighter in the line of duty experiences a wide range of exposures. Specifications for turnout gear focus primarily on pre-use performance. There is no standard for the performance of in-use fire fighter protective clothing. This paper outlines a research program designed to develop non-destructive test methods to provide users with an indication of how their in-use gear would conform to standards for new gear. Three non-destructive test methods (Raman luminescence, digital image analysis and colorimetry) are developed and correlated with established destructive tests to indicate useful service life. The paper concludes that among the methods examined in this study, digital image analysis offers the most promise for providing an economical and effective technique to assess the condition of in-use garments.
Can Laboratory Pre-Treatment Of Welders' Protective Clothing Simulate Their Aging Process In Normal Use?
Authors: Mäkinen H , Karkkula S , Jaakkola K , von Nandelstadh P
Published: October 2004

The fabrics of welders' protective garments can be worn out after only one or two use-wash cycles. It is probable that the by-products in the welding process, i.e., ultraviolet C-type (UVC) radiation, ozone, metal fumes, can contribute to the molecular changes responsible for the degradation. In this study we simulated the normal use of garments by cycling UVC/ozone and washing pre-treatments in the laboratory. In parallel, garments of the same five study fabrics were used by welders in a shipyard until the end of their service life. Properties defined in prEN ISO 11611 were measured from the laboratory-treated and the normally used fabrics. The laboratory cycling treatment affected tear resistance more than the tensile strength of the study fabrics. Both pre-treatments seemed to have affected the flammability of the fabrics similarly. The results of this study support the conception that it is possible to simulate the aging process of normally used garments by laboratory pre-treatments.
Survival of Adult Spiral Ganglion Neurons Requires erbB Receptor Signaling in the Inner Ear
Authors: Stankovic Konstantina , Rio Carlos , Xia Anping , Sugawara Mitsuru , Adams Joe C. , Liberman M. Charles , Corfas Gabriel
Published: October 2004

Degeneration of cochlear sensory neurons is an important cause of hearing loss, but the mechanisms that maintain the survival of adult cochlear sensory neurons are not clearly defined. We now provide evidence implicating the neuregulin (NRG)-erbB receptor signaling pathway in this process. We found that NRG1 is expressed by spiral ganglion neurons (SGNs), whereas erbB2 and erbB3 are expressed by supporting cells of the organ of Corti, suggesting that these molecules mediate interactions between these cells. Transgenic mice in which erbB signaling in adult supporting cells is disrupted by expression of a dominant-negative erbB receptor show severe hearing loss and 80% postnatal loss of type-I SGNs without concomitant loss of the sensory cells that they contact. Quantitative RT-PCR analysis of neurotrophic factor expression shows a specific downregulation in expression of neurotrophin-3 (NT3) in the transgenic cochleas before the onset of neuronal death. Because NT3 is critical for survival of type I SGNs during development, these results suggest that it plays similar roles in the adult. Together, the data indicate that adult cochlear supporting cells provide critical trophic support to the neurons, that survival of postnatal cochlear sensory neurons depends on reciprocal interactions between neurons and supporting cells, and that these interactions are mediated by NRG and neurotrophins.
Altered Social Behavior in Pituitary Adenylate Cyclase-Activating Polypeptide Type I Receptor-Deficient Mice
Authors: Nicot Arnaud , Otto Timothy , Brabet Philippe , DiCicco-Bloom Emanuel M.
Published: October 2004

The olfactory bulb plays a critical role in odor discrimination and in processing olfactory cues controlling social behavior in mammals. Given that the pituitary adenylate cyclase-activating polypeptide (PACAP) type 1 receptor (PAC1) is highly expressed in the olfactory bulb, we examined its role in regulating olfaction and social investigation. We found that olfactory detection of nonsocial stimuli was similar in PAC1-deficient mice and wild-type (WT) littermates. In contrast, PAC1-deficient mice displayed markedly abnormal social behaviors. PAC1-deficient mice exhibited a faster decrease in social investigation after repeated exposure to social cues or ovariectomized female urine compared with WT mice. Moreover, PAC1-deficient females exhibited delayed affiliative behavior when housed with novel males, and PAC1-deficient males displayed excessive sexual mounting toward both females and males as well as reduced aggression and increased licking and grooming toward intruder males. In aggregate, these results uncover PAC1 signaling as an important factor in the development and/or functioning of neural pathways associated with pheromone processing and the regulation of social interactions in mice. In turn, these studies raise the potential clinical relevance of PACAP signaling dysfunctions in neuropsychiatric disorders characterized by social reciprocity impairments such as autism spectrum disorders.
Coregulation of Glutamate Uptake and Long-Term Sensitization inAplysia
Authors: Khabour Omar , Levenson Jonathan , Lyons Lisa C. , Kategaya Lorna S. , Chin Jeannie , Byrne John H. , Eskin Arnold
Published: October 2004

InAplysia, long-term facilitation (LTF) at sensorimotor synapses of the pleural-pedal ganglia is mediated by an increase in the release of a neurotransmitter, which appears to be glutamate. Glutamate uptake also is increased in sensory neurons 24 hr after the induction of long-term sensitization (Levenson et al., 2000b). The present study investigated whether the same signaling pathways were involved in the long-term increase in glutamate uptake as in the induction of LTF. Thus, roles for cAMP, PKA (cAMP-dependent protein kinase), MAPK (mitogen-activated protein kinase), and tyrosine kinase in the regulation of glutamate uptake were tested. We found that 5-HT increased cAMP and activated PKA in sensory neurons. Exposure of pleural-pedal ganglia to analogs of cAMP or forskolin increased glutamate uptake 24 hr after treatments. Inhibitors of PKA (KT5720), MAPK (U0126 and PD98059), and tyrosine kinase (genistein) blocked the long-term increase in glutamate uptake produced by 5-HT. In addition, bpV, a tyrosine phosphatase inhibitor, facilitated the ability of subthreshold levels of 5-HT to increase glutamate uptake. Inhibition of PKC, which is not involved in LTF, had no effect on the long-term increase in glutamate uptake produced by 5-HT. Furthermore, activation of PKC by phorbol-12,13-dibutyrate did not produce long-term changes in glutamate uptake. The results demonstrate that the same constellation of second messengers and kinases is involved in the long-term regulation of both glutamate release and glutamate uptake. These similarities in signaling pathways suggest that regulation of glutamate release and uptake during formation of long-term memory are coordinated through coregulation of these two processes.
Switching of NMDA Receptor 2A and 2B Subunits at Thalamic and Cortical Synapses during Early Postnatal Development
Authors: Liu Xiao-Bo , Murray Karl D. , Jones Edward G.
Published: October 2004

Switching of the NMDA receptor 2A (NR2A) and NR2B subunits at NMDA receptors is thought to underlie the functional changes that occur in NMDA receptor properties during the developmental epoch when neural plasticity is most pronounced. The cellular expression of NR2A and NR2B and the NR2 synaptic binding protein postsynaptic density-95 (PSD-95) was examined in the mouse somatosensory cortex and thalamus from postnatal day 2 (P2) to P15 using reverse transcription-PCR,in situhybridization histochemistry, and immunocytochemistry. The localization of NR2A and NR2B subunits and PSD-95 was then studied at synapses in layer IV of somatosensory cortex and in the ventral posterior nucleus of the thalamus using high-resolution immunoelectron microscopy. At both cortical and thalamic synapses, a quantitative switch in the dominant synaptic subunit from NR2B to NR2A was accompanied by a similar change in the cellular expression of NR2A but not of NR2B. Synaptic PSD-95 developed independently, although both NR2A and NR2B colocalized with PSD-95. Displacement of NR2B subunits from synapses was not accompanied by an increase in an extrasynaptic pool of this subunit. Thus, the switch in synaptic NR2 subunit predominance does not occur by changes in expression or displacement from synapses and may reflect the formation of new synapses from which NR2B is lacking.
Detection and Masking of Spoiled Food Smells by Odor Maps in the Olfactory Bulb
Authors: Takahashi Yuji K. , Nagayama Shin , Mori Kensaku
Published: October 2004

Two major causes of spoiled food smells such as fatty, fishy off-flavors are alkylamines liberated by bacterial actions and aliphatic acids-aldehydes generated by lipid oxidation. Using the method of intrinsic signal imaging, we mapped alkylamine-responsive glomeruli to a subregion of the aliphatic acid-responsive and aldehyde-responsive cluster in the odor maps of rat olfactory bulb. Extracellular single-unit recordings from mitral-tufted cells in the subregion showed that individual cells responded to the alkylamines in addition to acids and aldehydes. Responses of mitral-tufted cells tended to last for a long period (5-88 sec) even after the cessation of the alkylamine stimulation. These results suggest that the subregion is part of the representation of the fatty, fishy odor quality. Fennel and clove, spices known to add flavor and mask the fatty, fishy odor, activated glomeruli in the surrounding clusters and suppressed the alkylamine-induced and acid-aldehyde-induced responses of mitral cells, suggesting that the odor masking is mediated, in part, by lateral inhibitory connections in the odor maps of the olfactory bulb.
Selection for Cognitive Control: A Functional Magnetic Resonance Imaging Study on the Selection of Task-Relevant Information
Authors: Brass Marcel , von Cramon D. Yves
Published: October 2004

The complex environment we live in makes it necessary to distinguish relevant from irrelevant information constantly and reliably. The aim of the present study was to investigate the neural substrate underlying the selection of task-relevant information. We devised a new paradigm in which participants had to switch between two different tasks that were instructed by task cues. The task cues had a relevant and an irrelevant cue dimension. In congruent trials, both cue dimensions indicated the same task; in incongruent trials, they indicated different tasks; and in neutral trials, only the relevant dimension indicated a task. By comparing trials in which both cue dimensions were informative (congruent and incongruent trials) with trials in which only the relevant dimension was informative (neutral trials), we were able to show that the lateral prefrontal cortex and a region in the intraparietal sulcus are involved in the selection of task-relevant information. Furthermore, the present paradigm allows the influence of the selected task and stimulus dimension to be investigated. No significant influence was found in the prefrontal cortex, indicating that this region serves a very abstract role in the selection of task-relevant information.
Timing and Balance of Inhibition Enhance the Effect of Long-Term Potentiation on Cell Firing
Authors: Marder Carrie P. , Buonomano Dean V.
Published: October 2004

The role of a neuron in neural processing is ultimately determined by whether or not it fires an action potential in a given context. Studies on synaptic plasticity have focused primarily on changes in EPSPs, and not on whether plasticity translates into changes in firing. However, this issue has been addressed by examining EPSP-spike (E-S) potentiation, which enhances the ability of an EPSP of a fixed slope to elicit spikes after long-term potentiation (LTP). Although LTP is thought to underlie learning and memory, E-S potentiation could play an equally important role by potentiating the neuronal input-output function. Here, we used a combined experimental and theoretical approach to examine both the mechanisms underlying E-S potentiation as well as the role of inhibition in shaping the input-output function of neurons. Whereas previous studies examined tetanus-LTP, in which inhibitory synapses may have undergone plasticity, here we examined pairing-induced associative LTP. We determined that although intact inhibition was necessary for pairing-induced E-S potentiation, inhibitory plasticity was not. We further established using computer simulations that a primary mechanism of E-S potentiation was a change in the relative recruitment and latency of inhibitory neurons. Although these studies do not exclude the presence of additional mechanisms of E-S potentiation that may be engaged depending on the induction protocol, they do establish that under intact pharmacology, LTP of the Schaffer collateral to CA1 pyramidal neuron synapses will produce E-S potentiation as a result of changes in the balance and timing of excitation and inhibition.
The GABAAReceptor γ2 Subunit R43Q Mutation Linked to Childhood Absence Epilepsy and Febrile Seizures Causes Retention of α1β2γ2S Receptors in the Endoplasmic Reticulum
Authors: Kang Jingqiong , Macdonald Robert L.
Published: October 2004

The GABAAreceptor γ2 subunit mutation R43Q is an autosomal dominant mutation associated with childhood absence epilepsy and febrile seizures. Previously, we demonstrated that homozygous α1β3γ2L(R43Q) receptor whole-cell currents had reduced amplitude with unaltered time course, suggesting reduced cell surface expression of functional receptors. In human embryonic kidney 293-T cells, we demonstrate that both heterozygous and homozygous α1β2γ2S(R43Q) GABAAreceptor current amplitudes were reduced when receptors were assembled from coexpressed α1, β2, and γ2S subunits and from β2-α1 tandem subunits coexpressed with the γ2L subunit. Using fluorescence confocal microscopy, we demonstrated that mutant receptors containing enhanced yellow fluorescent protein-tagged γ2S subunits had reduced surface expression and were retained in the endoplasmic reticulum. In addition, using biotinylation of surface receptors and immunoblotting, we confirmed that α1β2γ2S(R43Q) receptors had reduced surface expression. These results provide evidence that the γ2S(R43Q) mutation impaired GABAAreceptor function by compromising receptor trafficking and reducing surface expression.
Subunit-Dependent High-Affinity Zinc Inhibition of Acid-Sensing Ion Channels
Authors: Chu Xiang-Ping , Wemmie John A. , Wang Wei-Zhen , Zhu Xiao-Man , Saugstad Julie A. , Price Margaret P. , Simon Roger P. , Xiong Zhi-Gang
Published: October 2004

Acid-sensing ion channels (ASICs), a novel class of ligand-gated cation channels activated by protons, are highly expressed in peripheral sensory and central neurons. Activation of ASICs may play an important role in physiological processes such as nociception, mechanosensation, and learning-memory, and in the pathology of neurological conditions such as brain ischemia. Modulation of the activities of ASICs is expected to have a significant influence on the roles that these channels can play in both physiological and/or pathological processes. Here we show that the divalent cation Zn2+, an endogenous trace element, dose-dependently inhibits ASIC currents in cultured mouse cortical neurons at nanomolar concentrations. With ASICs expressed in Chinese hamster ovary cells, Zn2+inhibits currents mediated by homomeric ASIC1a and heteromeric ASIC1a-ASIC2a channels, without affecting currents mediated by homomeric ASIC1β, ASIC2a, or ASIC3. Consistent with ASIC1a-specific modulation, high-affinity Zn2+inhibition is absent in neurons from ASIC1a knock-out mice. Current-clamp recordings and Ca2+-imaging experiments demonstrated that Zn2+inhibits acid-induced membrane depolarization and the increase of intracellular Ca2+. Mutation of lysine-133 in the extracellular domain of the ASIC1a subunit abolishes the high-affinity Zn2+inhibition. Our studies suggest that Zn2+may play an important role in a negative feedback system for preventing overexcitation of neurons during normal synaptic transmission and ASIC1a-mediated excitotoxicity in pathological conditions.
Characterization of the c-Jun N-Terminal Kinase-BimELSignaling Pathway in Neuronal Apoptosis
Authors: Becker Esther B. E. , Howell Jenny , Kodama Yuki , Barker Philip A. , Bonni Azad
Published: October 2004

The c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in mediating apoptosis in the nervous system; however, the mechanisms by which JNK triggers neuronal apoptosis remain incompletely understood. Recent studies suggest that in addition to inducing transcription of pro-apoptotic genes, JNK also directly activates the cell death machinery. Here, we report that JNK catalyzed the phosphorylation of the BH3-only protein Bcl-2 interacting mediator of cell death (BimEL) at serine 65, bothin vitroandin vivo. The JNK-induced phosphorylation of BimELat serine 65 promoted the apoptotic effect of BimELin primary cerebellar granule neurons. We also characterized the role of the JNK-BimELsignaling pathway in apoptosis that was triggered by overexpression of the p75 neurotrophin receptor (p75NTR). We found that activation of p75NTRinduced the JNK-dependent phosphorylation of endogenous BimELat serine 65 in cells. The genetic knockdown of BimELby RNA interference or the expression of a dominant interfering form of BimELsignificantly impaired the ability of activated p75NTRto induce apoptosis. Together, these results suggest that JNK-induced phosphorylation of BimELat serine 65 mediates p75NTR-induced apoptosis. Our findings define a novel mechanism by which a death-receptor pathway directly activates the mitochondrial apoptotic machinery.
Recovery from Polyglutamine-Induced Neurodegeneration in ConditionalSCA1Transgenic Mice
Authors: Zu Tao , Duvick Lisa A. , Kaytor Michael D. , Berlinger Michael S. , Zoghbi Huda Y. , Clark H. Brent , Orr Harry T.
Published: October 2004

Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant, polyglutamine-induced neurodegenerative disorder that results in loss of motor coordination caused primarily by a disruption of cerebellar Purkinje cell function. In this study, we developed a conditionalSCA1mouse model to examine whether stopping expression of mutant ataxin-1 alters the disease phenotype. After cessation ofSCA1[82Q] transgene expression, mutant ataxin-1, including that in nuclear inclusions, was cleared rapidly from Purkinje cells. At an early stage of disease, Purkinje cell pathology and motor dysfunction were completely reversible. After haltingSCA1expression at later stages of disease, only a partial recovery was seen. Interestingly, restoration of the ability to perform a complex motor task, the accelerating Rotarod, correlated with localization of mGluR1α to the Purkinje cell-parallel fiber synapse. These results show that the progression of SCA1 pathogenesis is dependent on the continuous expression of mutant ataxin-1. Of note, even at a late stage of disease, Purkinje cells retain at least some ability to repair the damage caused by mutant ataxin-1.
Laminar Patterning in the Developing Neocortex by Temporally Coordinated Fibroblast Growth Factor Signaling
Authors: Hasegawa Hiroshi , Ashigaki Shizuko , Takamatsu Masako , Suzuki-Migishima Rika , Ohbayashi Norihiko , Itoh Nobuyuki , Takada Shinji , Tanabe Yasuto
Published: October 2004

Laminar organization, a fundamental neural architecture in the CNS, is a prominent feature of the neocortex, where the cortical neurons in spatially distinct layers are generated from the common progenitors in a temporally distinct manner during development. Despite many advances in the characterization of the molecular mechanisms of the radial migration of cortical neurons, the way in which the early-late temporal sequence of cortical neuron generation is linked with the deep-superficial spatial sequence of cell body positioning remains obscure. Usingin vivoelectroporation-mediated gene transfer, we show here that the activities mediated by fibroblast growth factor receptors (FGFRs) in cortical progenitors are critical for conferring proper migratory properties on nascent neuronal progeny. Furthermore, we provide supportive evidence that Pea3 subfamily members of Ets (Pea3-Ets) transcription factors mediate the activities of FGFR at the mid to late phase of neocortical development. In addition, usingFGF18knock-out mice, we demonstrate that FGF18 expressed by early-generated cortical neurons in the cortical plate is critical for the expression of Pea3-Ets transcription factors and that FGF18 is sufficient to induce their expressions. Our results thus imply that a feedback mechanism mediated by FGF signaling is involved in setting up the proper laminar positioning of cortical neurons; FGF18 derived from early-generated cortical neurons acts on the cortical progenitors expressing FGFRs and induces the expression of Pea3-Ets transcription factors that, in turn, confer proper migratory behaviors on nascent cortical progeny during the mid to late stages of neocortical development.
Mechanisms of Fast Ripples in the Hippocampus
Authors: Dzhala Volodymyr I. , Staley Kevin J.
Published: October 2004

Hippocampal fast ripples (FRs) have been associated with seizure onset in both human and experimental epilepsy. To characterize the mechanisms underlying FR oscillations (200-600 Hz), we studied activity of single neurons and neuronal networks in rat hippocampal slicesin vitro. The correlation between the action potentials of bursting pyramidal cells and local field potential oscillations suggests that synchronous onset of action potential bursts and similar intrinsic firing patterns among local neurons are both necessary conditions for FR oscillations. Increasing the fidelity of individual pyramidal cell spike train timing by blocking accommodation dramatically increased FR amplitude, whereas blockade of potassium conductances decreased the fidelity of action potential timing in individual pyramidal cell action potential bursts and decreased FR amplitude. Blockade of ionotropic glutamate receptors desynchronized onset of action potential bursts in individual pyramidal cells and abolished fast ripples. Thus, synchronous burst onset mediated by recurrent excitatory synaptic transmission and similar intrinsic spike timing mechanisms in neighboring pyramidal cells are necessary conditions for FR oscillations within the hippocampal network.
SynGAP Regulates Spine Formation
Authors: Vazquez Luis E. , Chen Hong-Jung , Sokolova Irina , Knuesel Irene , Kennedy Mary B.
Published: October 2004

SynGAP is a brain-specific ras GTPase-activating protein that is an abundant component of the signaling complex associated with the NMDA-type glutamate receptor. We generated mutant mice lacking synGAP to study its physiological role. Homozygous mutant mice die in the first few days after birth; however, neurons from mutant embryos can be maintained in culture. Here, we report that spine and synapse formation are accelerated in cultured mutant neurons, and the spines of mature mutant neurons are significantly larger than those of wild type. Clusters of PSD-95 and subunits of AMPA-type and NMDA-type glutamate receptors accumulate in spines of mutant neurons by day 10in vitro, whereas in wild-type neurons they are still mostly located in dendritic shafts. The frequency and amplitude of miniature EPSCs are larger in mutant neurons at day 10in vitro, confirming that they have more functional synapses. At day 21in vitro, the spines of mutant neurons remain significantly larger than those of wild type. The mutant phenotype at day 10in vitrocan be rescued by introduction of recombinant wild-type synGAP on day 9. In contrast, introduction of mutant synGAP with a mutated GAP domain or lacking the terminal domain that binds to PSD-95 does not rescue the mutant phenotype, indicating that both domains play a role in control of spine formation. Thus, the GAP activity of synGAP and its association with PSD-95 are important for normal regulation of spine and synapse formation in hippocampal neurons.
Reducing the Uncertainty: Gating of Peripheral Inputs by Zona Incerta
Authors: Trageser Jason C. , Keller Asaf
Published: October 2004

Sensory inputs are relayed to the neocortex by “first-order” thalamic nuclei, the responses of which are determined by ascending inputs from peripheral receptors. In contrast, “higher-order” thalamic nuclei respond poorly to peripheral inputs, and their responses are thought to be determined by descending cortical inputs. We tested this hypothesis by recording from neurons in the higher-order somatosensory posterior medial (POm) nucleus of narcotized rats. As reported previously, POm neurons responded to whisker stimuli with long-latency (median, 27 msec) and low-magnitude responses, consistent with cortically driven responses. However, when we suppressed inhibitory inputs from the subthalamic nucleus zona incerta (ZI), POm responses were of significantly higher magnitude and shorter latency, with many POm neurons responding at latencies consistent with ascending driving inputs from trigeminal nuclei. Our data suggest that POm comprises two neuronal populations: one population is driven by both peripheral and cortical inputs, and the second population responds only to cortical inputs. These findings demonstrate that ZI gates peripheral inputs to POm, enabling it to function both as a first-order and higher-order nucleus. Because ZI innervates all higher-order nuclei, this gating mechanism may exert similar regulation of thalamic processing in other sensory systems.
The Role of cAMP Response Element-Binding Protein inDrosophilaLong-Term Memory
Authors: Perazzona Bastianella , Isabel Guillaume , Preat Thomas , Davis Ronald L.
Published: October 2004

InDrosophila,the transcription factor cAMP response element-binding protein 2 (dCREB2) has been reported to modulate the formation of long-term olfactory memory (LTM). Overexpression of a repressor isoform of CREB (dCREB2-b) under the control of a heat-shock promoter was reported to block LTM, whereas overexpression of an activator isoform (dCREB2-a) was reported to enhance LTM. A ratiometric model based on these results predicts that the balance of functional dCREB2-a and dCREB2-b provides a switch for memories to remain labile or to become enduring. We show here that the dCREB2-a transgene originally reported to enhance LTM carries a mutation that produces a translational reading-frame shift with the consequent formation of a stop codon at predicted amino acid position 79. Overexpression of this mutant dCREB2-a transgene or a corrected dCREB2-a transgene failed to show any enhancement of LTM. Overexpression of the dCREB2-b repressor transgene, in contrast, produced the anticipated block in LTM formation. We discuss the implications of these findings and propose an alternative model for the role of dCREB inDrosophilaLTM.
Development of an extrusion system for producing fine‐celled HDPE/wood‐fiber composite foams using CO2as a blowing agent
Authors: Zhang H. , Rizvi G. M. , Park C. B.
Published: October 2004

This paper presents an innovative design of a tandem extrusion system for fine‐celled foaming of plastic/wood‐fiber composites using a physical blowing agent (PBA). The plastic/wood‐fiber composites utilize wood‐fibers (WF) as a reinforcing filler in the plastic matrix and are known to be advantageous over the neat plastics in terms of the materials cost and some improved mechanical properties such as stiffness and strength. However, these improvements are usually accompanied by sacrifices in the ductility and impact resistance. These shortcomings can be reduced by inducing fine‐celled or microcellular foaming in these composites, thereby creating a new class of materials with unique properties. An innovative tandem extrusion system with continuous on‐line moisture removal and PBA injection was successfully developed. The foamed composites, produced on the tandem extrusion system, were compared with those produced on a single extruder system, and demonstrated significant improvement in cell morphology, resulting from uniform mixing and effective moisture removal. The effects of WF and coupling agent (CA) on the cell morphology were studied. An increase in the WF content had an adverse affect. The cell morphology and foam structures were improved when an appropriate CA was added. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 263–276, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20016
Cotton producers' choice of marketing techniques
Authors: Vergara Oscar , Coble Keith H. , Knight Thomas O. , Patrick George F. , Baquet Alan E.
Published: October 2004

A survey of cotton producers was conducted in Mississippi and Texas. The econometric model consists of a multinomial logit model of cotton producers' choice of marketing techniques. The results indicate that cotton acres positively influence pooling and negatively influence cash sales. Producers willing to incur higher transaction costs in market information systems and training tend to choose futures/options contracts and forward pricing. It was found that risk‐averse producers tend not to choose pooling contracts. On the other hand, producers who seek abnormal gains through speculation tend to choose pooling contracts. Finally, producers who perceive markets as being price‐efficient prefer cash sales. [EconLit citation: Q130.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 465–479, 2004.
The genetics of skin cancer
Authors: Tsai Kenneth Y. , Tsao Hensin
Published: October 2004

Recent advances in molecular genetics have led to a better understanding of the biological underpinnings of skin cancer formation. As with most cancers, the RB, p53, and RAS pathways appear to play prominent roles in the pathogenesis of several skin cancer types. Although various components of these pathways may be differentially altered in squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and cutaneous melanoma, the final biochemical expression of these defects may be the same. With the unraveling of these genetic mechanisms, a more targeted approach to diagnosis and treatment may be possible in the near future. © 2004 Wiley‐Liss, Inc.
Gene therapy and the skin
Authors: Hengge U.R. , Bardenheuer W.
Published: October 2004

Significant progress has been made during the past decade in corrective gene therapy of the skin. This includes advances in vector technology, targeted gene expression, gene replacement, gene correction, and the availability of appropriate animal models for a variety of candidate diseases. While non‐viral integration of large genes such as essential basement membrane proteins has been mastered, new challenges such as the control of immune responses lie ahead of the research community. Among the first skin diseases, patients with junctional epidermolysis bullosa (JEB) and xeroderma pigmentosum (XP) will enter clinical trials. © 2004 Wiley‐Liss, Inc.
Social structure and life‐history patterns in western gorillas (Gorilla gorilla gorilla)
Authors: Robbins Martha M. , Bermejo Magdelena , Cipolletta Chloé , Magliocca Florence , Parnell Richard J. , Stokes Emma
Published: October 2004

Life‐history traits and ecological conditions have an important influence on primate social systems. Most of what we know about the life‐history patterns and social structure of gorillas comes from studies of eastern gorillas (Gorilla beringei sp.), which live under dramatically different ecological conditions compared to western gorillas (Gorilla gorilla sp.). In this paper we present new data on western gorilla social structure and life histories from four study sites, and make comparisons with eastern gorilla populations. Data were obtained from two study sites with gorilla groups undergoing the habituation process (Lossi, Democratic Republic of Congo and Bai Hokou, Central African Republic) and two “bai” studies (Maya Nord and Mbeli Bai, Republic of Congo). The size and structure of these groups were similar to those seen in eastern gorillas. However, differences in the occurrence of various group transitions (group formations, changes between one‐male and multimale composition, and group disintegrations) exist, and western gorillas notably exhibit much higher rates of male emigration and correspondingly fewer multimale groups compared to mountain gorillas. Certain phenomena have been observed only rarely, including predation by leopards. The preliminary data show no significant differences in birth rates between western gorillas and mountain gorillas. The ecological variability across gorilla habitats likely explains the flexibility in the social system of gorillas, but we need more information on the social relationships and ecology of western gorillas to elucidate the causes for the similarities and differences between western and eastern gorillas on the levels of individuals, social groups, and population dynamics. Am. J. Primatol. 64:145–159, 2004. © 2004 Wiley‐Liss, Inc.
Genetic variation in gorillas
Authors: Vigilant Linda , Bradley Brenda J.
Published: October 2004

This review summarizes what is currently known concerning genetic variation in gorillas, on both inter‐ and intraspecific levels. Compared to the human species, gorillas, along with the other great apes, possess greater genetic varation as a consequence of a demographic history of rather constant population size. Data and hence conclusions from analysis of mitochondrial DNA (mtDNA), the usual means of describing intraspecific patterns of genetic diversity, are limited at this time. An important task for future studies is to determine the degree of confidence with which gorilla mtDNA can be analyzed, in view of the risk that one will inadvertently analyze artifactual rather than genuine sequences. The limited information available from sequences of nuclear genomic segments does not distinguish western from eastern gorillas, and, in comparison with results from the two chimpanzee species, suggests a relatively recent common ancestry for all gorillas. In the near future, the greatest insights are likely to come from studies aimed at genetic characterization of all individual members of social groups. Such studies, addressing topics such as behavior of individuals with kin and non‐kin, and the actual success of male reproductive strategies, will provide a link between behavioral and genetic studies of gorillas. Am. J. Primatol. 64:161–172, 2004. © 2004 Wiley‐Liss, Inc.
Western gorilla diet: A synthesis from six sites
Authors: Rogers M. Elizabeth , Abernethy Kate , Bermejo Magdalena , Cipolletta Chloe , Doran Diane , Mcfarland Kelley , Nishihara Tomoaki , Remis Melissa , Tutin Caroline E.G.
Published: October 2004

The objective of this paper is to collate information on western gorilla diet from six study sites throughout much of their current range, including preliminary information from two sites (Afi and Lossi), where studies of diet have begun only recently. Food lists were available from each site, derived from indirect signs of gorilla feeding (such as feces), with some observational data. Important staple, seasonal, and fallback foods have been identified, and a number of striking similarities across sites have been revealed based on a much larger data set than was previously available. It was confirmed that the western gorilla diet is always eclectic, including up to 230 items and 180 species. The greatest diversity is found among the fruit species eaten, fruit being included in western gorilla diets from all sites and throughout most or all of the year. Eight plant families provide important foods at five, or all six, sites, suggesting that it may be possible in the future to predict which habitats are the most suitable for gorillas. Gorillas exploit both rare and common forest species. Similarities and differences among sites can be explained superficially on the basis of geography and the past history of the forest. Gorilla density across sites appears to be most affected by the density of monocotyledonous bulk food plants, but its relationship to the density of important tree food species has yet to be tested. Am. J. Primatol. 64:173–192, 2004. © 2004 Wiley‐Liss, Inc.
Effects of group dynamics and diet on the ranging patterns of a western gorilla group (Gorilla gorilla gorilla) at Bai Hokou, Central African Republic
Authors: Cipolletta Chloé
Published: October 2004

This study describes how group dynamics and diet have influenced the ranging patterns of a western gorilla group at Bai Hokou, Central African Republic. The results are compared with those from an earlier study [Cipolletta, International Journal of Primatology, 2003], when the same group was larger and undergoing the process of habituation to humans. Data were obtained from maps of the gorillas' travel routes, direct observations, and analysis of fecal samples. Through the years, the group has experienced a decrease in size, from eight to three individuals, with periods of membership fluctuation. The male's search for new mates resulted in a larger home range than was recorded when the group consisted of more individuals. Moreover, despite an average group size of three throughout this study, the monthly range and mean daily path length (DPL) were also larger when the group was acquiring/losing members in new areas, than when no new members joined or left the group. Fruit was consumed year‐round, although more heavily so during wet months. The influence of fruit consumption on the ranging patterns was concealed initially by the effect of habituation [Cipolletta, International Journal of Primatology, 2003], and later (at least partially) by the male's search for new mates. In the last 14 months of the study, when the group numbered only three individuals and was ranging in a restricted area, the average DPL, but not the monthly range, increased when the gorillas were consuming more fruit. Am. J. Primatol. 64:193–205, 2004. © 2004 Wiley‐Liss, Inc.
Home‐range use and intergroup encounters in western gorillas (Gorilla g. gorilla) at Lossi forest, North Congo
Authors: Bermejo M.
Published: October 2004

I present data on home‐range use and types of intergroup encounters for one group (Apollo) of western gorillas (Gorilla gorilla gorilla) from a new study site in the Republic of Congo. The total home‐range size of the focal group, which I calculated by superimposing a 100 m × 100 m grid over the mapped daily path traveled, was 11 km2. The majority (73%) of the group's home range was used exclusively, although at the periphery it overlapped with the ranges of three other groups. Most encounters (86%) with other groups (n = 14) took place in the periphery of the home range, and appeared to involve access to fruit trees. The focal group silverback's encounters with solitary silverbacks occurred throughout the focal group's home range, did not involve access to fruit, and typically resulted in aggressive or avoidance behavior. The focal group silverback's response to other group males was more varied: it included tolerance (64%), avoidance (14%), and aggression (21%), and was dependent upon the identity of the extragroup male. The focal group exhibited an unusual form of tolerant behavior toward some other groups by occasionally forming “nesting supergroups” (two groups nested together overnight at distances of 30–50 m). The western gorillas at Lossi were somewhat fluid in their grouping. Subgrouping and supergrouping occurred, although more infrequently than reported previously, and with a new twist: subgrouping did not necessarily require a silverback's presence. I stress the need for intraspecific comparisons and more complete data sets on western gorilla social organization. Am J Primatol 64:223–232, 2004. © 2004 Wiley‐Liss, Inc.
Connexin 32 promoter P2 mutations: A mechanism of peripheral nerve dysfunction
Authors: Houlden Henry , Girard Mathilde , Cockerell Charles , Ingram David , Wood Nicholas W. , Goossens Michel , Walker Rodney W. H. , Reilly Mary M.
Published: October 2004

We identified a large Charcot–Marie–Tooth disease family with a novel mutation in the Connexin 32 (Cx32) P2 promoter region at position −526bp. This mutation was in a highly conserved SOX10 binding site. Functional studies were conducted on the Cx32 promoter that showed that this mutation reduced the activity of the Cx32 promoter and the affinity for SOX10 binding. These data suggest that interaction between the Cx32 P2 promoter, SOX10, and EGR2 highlight a mechanism of peripheral nerve dysfunction. Ann Neurol, 2004
Prolongation of levodopa responses by glycineB antagonists in parkinsonian primates
Authors: Papa Stella M. , Auberson Yves P. , Greenamyre J. Timothy
Published: October 2004

To examine the antiparkinsonian effects of blocking glycineB receptors, we designed a pilot study testing the potent and selective antagonist, PAMQX, in 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine‐treated primates. PAMQX had no intrinsic effects but markedly potentiated the antiparkinsonian action of levodopa. In a dose‐dependent fashion, coadministration of the glycineB antagonist with levodopa extended the response duration by nearly 60%. It is noteworthy that PAMQX, within a considerable dose range, did not cause ataxia or other side effects. These data indicate that blocking N‐methyl‐D‐aspartate receptors selectively to manipulate dopaminergic‐mediated motor responses may be produced effectively by glycineB antagonists. Ann Neurol 2004
Titelbild: Chiral Centers in the Side Chains of α‐Amino Acids Control the Helical Screw Sense of Peptides (Angew. Chem. 40/2004)
Authors: Tanaka Masakazu , Demizu Yosuke , Doi Mitsunobu , Kurihara Masaaki , Suemune Hiroshi
Published: October 2004

Tidenstrudel die sowohl rechts‐ als auch linksgängig sein können, entstehen, wenn ein starker Tidenstrom auf ruhige See trifft (das Foto der Naruto City Tourist Association zeigt ein Beispiel vom Naruto‐Kanal in Japan). Dagegen sind die α‐Helices von Proteinen wegen der stereogenen α‐Kohlenstoffzentren von α‐Aminosäuren fast immer rechtsgängig. M. Tanaka et al. stellen nun auf S. 5474 ff. ein α‐helicales Peptid vor, dessen Linksgängigkeit durch die stereogenen Zentren der Seitenketten festgelegt wird.
Cover Picture: Chiral Centers in the Side Chains of α‐Amino Acids Control the Helical Screw Sense of Peptides (Angew. Chem. Int. Ed. 40/2004)
Authors: Tanaka Masakazu , Demizu Yosuke , Doi Mitsunobu , Kurihara Masaaki , Suemune Hiroshi
Published: October 2004

A tidal vortex (helix) is formed, both right‐ and left‐handed, where a violent tidal current meets a peaceful sea (the picture from Naruto City Tourist Association shows an example at Naruto channel, Japan). In contrast, α‐helices of proteins almost always show a right‐handed helical screw sense because of the stereogenic α‐carbon center of α‐amino acids. M. Tanaka et al. now demonstrate on page 5360 ff. how the left‐handedness of a α‐helical peptide is controlled by the side‐chain stereogenic centers.