bluuebunny/crossref_metadata_2025 huggingface dataset:
Rat Head Direction Cell Responses in Zero-Gravity Parabolic Flight
Authors: Taube Jeffrey S. , Stackman Robert W. , Calton Jeffrey L. , Oman Charles M.
Published: June 2004

Astronauts working in zero-gravity (0-G) often experience visual reorientation illusions (VRIs). For example, when floating upside down, they commonly misperceive the spacecraft floor as a ceiling and have a reversed sense of direction. Previous studies have identified a population of neurons in the rat's brain that discharge as a function of the rat's head direction (HD) in a gravitationally horizontal plane and is dependent on an intact vestibular system. Our goal was to characterize HD cell discharge under conditions of acute weightlessness. Seven HD cells in the anterior dorsal thalamus were monitored from rats aboard an aircraft in 0-G parabolic flight. Unrestrained rats locomoted in a clear plexiglas rectangular chamber that had wire mesh covering the floor, ceiling, and one wall. The chamber and surrounding visual environment were relatively up-down symmetrical. Each HD cell was recorded across forty 20-s episodes of 0-G. All HD cells maintained a significant direction-specific discharge when the rat was on the chamber floor during the 0-G and also during the hypergravity pull-out periods. Three of five cells also showed direction-specific responses on the wall in 1-G. In contrast, direction-specific discharge was usually not maintained when the rat locomoted on the vertical wall or ceiling in 0-G. The loss of direction-specific firing was accompanied by an overall increase in background firing. However, while the rat was on the ceiling, some cells showed occasional bursts of firing when the rat's head was oriented in directions that were flipped relative to the long axis of symmetry of the chamber compared with the cell's preferred firing direction on the floor. This finding is consistent with what might be expected if the rat had experienced a VRI. These responses indicate that rats maintain a normal allocentric frame of reference in 0-G and 1-G when on the floor, but may lose their sense of directional heading when placed on a wall or ceiling during acute exposures to 0-G.
Time Course of Vestibuloocular Reflex Suppression During Gaze Shifts
Authors: Cullen Kathleen E. , Huterer Marko , Braidwood Danielle A. , Sylvestre Pierre A.
Published: June 2004

Although numerous investigations have probed the status of the vestibuloocular (VOR) during gaze shifts, its exact status remains strangely elusive. The goal of the present study was to precisely evaluate the dynamics of VOR suppression immediately before, throughout, and just after gaze shifts. A torque motor was used to apply rapid (100°/s), short-duration (20–30 ms) horizontal head perturbations in three Rhesus monkeys. The status of the VOR elicited by this transient head perturbation was first compared during 15, 40, and 60° gaze shifts. The level of VOR suppression just after gaze-shift onset (40 ms) increased with gaze-shift amplitude in two monkeys, approaching values of 80 and 35%. In contrast, in the third monkey, the VOR was not significantly attenuated for all gaze-shift amplitudes. The time course of VOR attenuation was then studied in greater detail for all three monkeys by imposing the same short-duration head perturbations 40, 100, and 150 ms after the onset of 60° gaze shifts. Overall we found a consistent trend, in which VOR suppression was maximal early in the gaze shift and progressively recovered to reach normal values near gaze-shift end. However, the high variability across subjects prevented establishing a unifying description of the absolute level and time course of VOR suppression during gaze shifts. We propose that differences in behavioral strategies may account, at least in part, for these differences between subjects.
Between a Defence of Society and a Politics of the Subject: The Specificity of Today’s Social Movements
Authors: Dubet François
Published: June 2004

The globalization of exchanges and flux has considerably weakenedthe political arena on the national level in which social movements have previously developed. To a large extent, social movements today try to counteract this tendency by calling upon such frameworks for integration as national populism or diverse forms of communitarianism. As far as the workers’ movement is concerned, the tendency is either for corporatism or for radical opposition to the system. But there exist other cultural rather than social movements which have made peace with the demise of traditional representations of social life and whose main focus is on the experience of individuals. These movements are based on the theme of individual moral autonomy which has been impeded by destructive social changes and by the forms of domination they have produced. Hence, these movements do not so much call for social integration as they do for justice and for a politics of recognition of the individual subject. They seek to avoid both the constraints of free market regulations and the seclusion within collective identities.
On the Frontier of Social Movements
Authors: Touraine Alain
Published: June 2004

The author argues that globalization has shifted the nature of conflicts considerably, to the point that the social movements are no longer those that set social categories in opposition to one another, as in the case of social classes. Dominant forces define themselves no longer by content or by forms of social life, but by an unlimited capacity for change or adaptation to an environment that is in constant modification and often unpredictable. The key question for social movements no longer has to do with defining an autonomous space or time, but, rather, with recognizing the priority that must be given to the creation – much more than to the defence – of an autonomy that is less professional or economic than moral – that is, the autonomy of the individual, considered as an actor, or, more precisely, as a subject. This is why it is preferable to replace the expression ‘social movements’ with that of ‘cultural movements’.
Politics at the Water’s Edge
Authors: Ramsay Kristopher W.
Published: June 2004

The role of domestic politics is investigated, using a model to show how domestic opposition during a crisis can reveal to a rival state private information about the incumbent. In particular, the public nature of democratic competition results in the institutionally induced credibility of the message.
On Requesting Re-Prints Electronically
Authors: Hartley James
Published: June 2004

Background. Many researchers contact colleagues in order to obtain re-prints of their papers. Most people, these days, use electronic aids to do this.

Aim. The aim of this study was to compare the success rates for obtaining re-prints using such electronic communication with those obtained previously by post.

Method. A hundred requests for e-prints or re-prints were sent electronically to colleagues, and the response rates recorded.

Results. Of those approached, 79% responded to the requests, although 12% of these needed a reminder. Those replying electronically without a reminder (41%) took an average of one day to respond (range 0-13 days), whereas those replying by mail without a reminder (26%) took on average nine days (range 2-34 days). Responders needing a reminder (12%) took on average 41 days to respond (range 32-71). There were no significant differences between the response rates of American and British researchers, nor between those of men and women, but there was a significantly higher response rate from colleagues who were sent accompanying materials with the request. Conclusions. These results indicate that rapid replies were received from people responding electronically and that the overall response rate was somewhat higher, and somewhat faster, than that found in most previous postal studies. However, the problem of non- and late-responders still exists. One further advantage for the electronic system is that, unlike the postal method, it facilitates rapid additional communication between the sender and the recipient.
The Genocidal Past in Western Germany and the Experience of Occupation, 1945-6
Authors: Bloxham Donald
Published: June 2004

This article examines the re-educational aspect of the Anglo-American occupation of western Germany in 1945-6. It interrogates some of the key methods, messages and goals of the re-education programme with particular reference to the representation of Nazi genocide and the question of responsibility for it. It suggests that Allied policy contributed significantly, if often inadvertently, to fostering the two overriding postwar German responses to wartime atrocity and Nazism: the rejection of responsibility and the ‘relativization’, and even minimization, of the crimes committed.
Externalizing and Internalizing Problems in Low-Income Latino Early Adolescents
Authors: Loukas Alexandra , Prelow Hazel M.
Published: June 2004

The current investigation examined the role of cumulative risk, family routines, maternal monitoring, mother-child relationship quality, and youth socioemotional competence in adjustment outcomes of 521 10- to 14-year-old low-income Latino early adolescents. Results showed that, as the number of risk factors increased, levels of externalizing and internalizing problems also increased. Furthermore, findings indicated that socio-emotional competence was predictive of fewer externalizing and internalizing problems for females independent of the level of cumulative risk. Maintenance of family routines protected females exposed to elevated levels of cumulative risk from heightened levels of externalizing problems. Despite exposure to multiple risk factors, boys high in socio-emotional competence and those boys reporting a good quality mother-son relationship were protected from elevated levels of adjustment problems. Results underscore the importance of examining within-group variability among young Latino adolescents.
A Neural Network Applied to Criminal Psychological Profiling: An Italian Initiative
Authors: Strano Marco
Published: June 2004

The author presents a brief discussion of criminal profiling followed by an introduction to the Italian Neural Network for Psychological Criminal Profiling (NNPCP) project. This project, based on a so-called neural network and data mining, is an innovative technique being developed with the intention of extending criminal profiling to single serious crimes through the use of a computerized database.
Moisture Absorption Behavior of Carbon Fiber-Reinforced Monomer Casting Nylon Composites
Authors: Wan X. F. , Wang Y. L. , Zhou F. G. , Wan Y. Z.
Published: June 2004

A series of tests were conducted to study the moisture absorption behaviors of carbon fiber-reinforced monomer casting nylon (CF/MC) composites with fiber contents of 10 and 15 vol.%, and their effects on mechanical properties. The results show that the moisture absorption behavior of the CF/MC composites obeys a Fickian relationship. The maximum moisture uptake has been found to decrease with the increase of carbon fiber volume fraction. The moisture absorption rate and the time to reach the saturation fall as the immersion medium temperature increases. Furthermore, a great increase in moisture content and absorption rate is observed as the pH values of the medium decrease. It is observed that moisture intake has a deleterious effect on the mechanical properties (bending strength and hardness) of the CF/MC composites. Scanning electron microscopy (SEM) has been used to examine the shear and impact surfaces of the composites, and the findings of SEM observations are consistent with those of the moisture absorption experiments.
Corrosion Behavior of Carbon Reinforced Plain-Weave Laminates
Authors: Ahmad Zaki , Al-Sulaiman Faleh , Aleem B. J. Abdul
Published: June 2004

The corrosion performance of carbon reinforced plain-weave laminates in 3.5% NaCl solution was evaluated by different corrosion measurement techniques to determine the suitability for applications in a corrosive environment. Based on the experimental studies it was observed that this composite offers a high resistance to corrosion in 3.5% NaCl solution both in static and in flow velocity up to 1.8 m/s.
Orientation of the Permeability Principal Axes in Bi-Directional Textile Fabrics
Authors: Endruweit A. , Ermanni P.
Published: June 2004

For various commercial woven glass fiber fabrics, the orientation of the permeability principal axes has been experimentally determined as function of the fiber angle, carrying out two-dimensional flow experiments with radial liquid injection. The investigated fabrics have in general been found to significantly show anisotropic properties even for the unsheared material. The orientation of the permeability principal axes of sheared fabrics is related to the degree of anisotropy, characterized by the ratio of the permeability principal values for the unsheared fabrics. The orientation of the permeability principal axes as a function of the fiber angle is described by an empirical formula, with the ratio of the permeability principal values of the unsheared fabric as parameter. Comparison of experimental and theoretical results in general indicates correspondence. Exceptions can be explained by uncertainties in the experimentally determined permeability principal values of the unsheared fabric.
The Effects of Hygrothermal Conditions on the Dynamic Response of Shear Deformable Laminated Plates Resting on Elastic Foundations
Authors: Shen Hui-Shen , Zheng Jian-Jun , Huang Xiao-Lin
Published: June 2004

The effect of hygrothermal conditions on the dynamic response of shear deformable laminated plates resting on a two-parameter (Pasternak-type) elastic foundation is investigated using a micro-to-macromechanical analytical model. The material properties of the composite are affected by the variation of temperature and moisture, and are based on a micromechanical model of a laminate. The governing equations are based on higher order shear deformation plate theory and include the plate-foundation interaction and hygrothermal effects. All four edges of the plate are assumed to be simply supported with no in-plane displacements. Analytical solutions of dynamic response for symmetric cross-ply and antisymmetric angle-ply laminated plates subjected to a transverse dynamic load under different sets of hygrothermal environmental conditions are obtained by using the state variable approach. The numerical illustrations concern the free vibration and dynamic response of shear deformable laminated plates resting on Pasternak-type elastic foundations with the Winkler elastic foundations being a limiting case. The influences played by temperature rise, the degree of moisture concentration, fiber volume fraction and foundation stiffness are studied. The results show that the hygrothermal environment has a significant effect on the natural frequency as well as dynamic response of the plate.
In Vitro Attachment of Staphylococcus Epidermidis to Surgical Sutures with and without Ag-Containing Bioactive Glass Coating
Authors: Pratten Jonathan , Nazhat Showan N. , Blaker Jonny J. , Boccaccini Aldo R.
Published: June 2004

The ability of a silver-doped bioactive glass (AgBG) coating to prevent bacterial colonization on surgical sutures was investigated in vitro. Bioactive glass powders, in the form of 45S5 Bioglass® and AgBG, were used to coat Mersilk® sutures using an optimized ‘in house’ slurry-dipping process. In vitro experiments were carried out using Staphylococcus epidermidis under both batch and flow conditions. While the traditional batch culture testing was used to determine the number of viable cells adhered to the surface, the flow-cell was used to visualize attachment and detachment over time. Under batch conditions of up to 180 min, statistically significant differences were observed in the colony forming units (CFU) per suture for both the coated and uncoated Mersilk® sutures. The results showed that the AgBG coating had the greatest effect on limiting bacterial attachment (8 102 CFU) when compared to the 45S5 Bioglass® coating (3.2 103 CFU) and the uncoated Mersilk® (1.2 104 CFU). Also under flow conditions differences were seen between the coated and uncoated sutures. Therefore, this preliminary study has demonstrated the quantification and visualization of bacterial attachment onto sutures in order to compare the antibacterial properties of Ag-containing bioactive glass coatings. The bactericidal properties imparted by Ag-containing glass open new opportunities for use of the composite sutures in wound healing and body wall repair.
Surface Modification and Characterization of Chitosan Film Blended with Poly-L-Lysine
Authors: Mingyu Cheng , Kai Gong , Jiamou Li , Yandao Gong , Nanming Zhao , Xiufang Zhang
Published: June 2004

Biodegradable nerve guidance conduits (NGCs) represent a promising alternative to current clinical nerve repair procedures. Chitosan, a natural polysaccharide that has excellent biocompatibility and biodegradability, can be used as a nerve conduit material. The purpose of this work was to study the nerve cell affinity of chitosan modified by blending with different content of poly-L-lysine. PC12 cells culture was used to evaluate the nerve cell affinity of the chitosan-poly-L-lysine composite materials. The results showed that composite materials had significantly improved nerve cell affinity compared to chitosan as indicated by increased attachment, differentiation, and growth of nerve cells. The improved nerve cell affinity might be due to both the increased surface charge and hydrophilicity of composite materials. Composite material with 3 wt% poly-L-lysine content (PL-3) is an even better material in nerve cell affinity than collagen, suggesting that poly-L-lysine-blended chitosan is a promising candidate material for nerve regeneration.
Gender As a Social Structure
Authors: Risman Barbara J.
Published: June 2004

In this article, the author argues that we need to conceptualize gender as a social structure, and by doing so, we can better analyze the ways in which gender is embedded in the individual, interactional, and institutional dimensions of our society. To conceptualize gender as a structure situates gender at the same level of general social significance as the economy and the polity. The author also argues that while concern with intersectionality must continue to be paramount, different structures of inequality have different constructions and perhaps different influential causal mechanisms at any given historical moment. We need to follow a both/and strategy to understand gender structure, race structure, and other structures of inequality as they currently operate while also systematically paying attention to how these axes of domination intersect. Finally, the author suggests we pay more attention to doing research and writing theory with explicit attention to how our work can indeed help transform as well as inform society.
Electron Beam Strengthening for Carbon Fiber-Reinforced Composite Materials
Authors: Nishi Yoshitake , Mizutani Akihiro , Uchida Nobuhiro
Published: June 2004

In order to evaluate the influence of electron beam (EB) irradiation on the elasticity and stress–strain curve of composite materials reinforced by carbon fiber (CF), carbon fiber-reinforced polymer (CFRP) and carbon fiber-reinforced graphite (C–C) were treated by EB irradiation of 0.3 MGy. Since the EB strengthening was mainly dominated by the ductility enhancements of carbon fiber and matrix of epoxy resin, EB irradiation enlarged fracture stress and enhanced fracture strain of CFRP. Furthermore, EB irradiation slightly enhanced bending elasticity of CFRP and largely enhanced the initial spring constant related to elasticity of C–C coil. Although the elasticity enhancement of carbon fibers did not largely contribute to that of CFRP, that of treated graphite matrix in C–C mainly caused the C–C coil elasticity enhancement by EB irradiation. Such a new treatment is a dream-worthy technology for structural materials to be applied in the fields of future engineering.
Effective Enforcement of EC Labour Law: A Comparative Analysis of Community Law Requirements
Authors: Malmberg Jonas
Published: June 2004

This article deals with the rules designed to enforce European Union labour law in the workplace. Directives do not normally provide specific rules on procedures and sanctions according to which their substantive provisions are to be enforced. Instead, domestic rules are to be applied. The European Court of Justice, however, has developed some requirements that limit the autonomy of the Member States in this area. The aim of this article is to evaluate the principle of effective enforcement in the field of labour law, in the light of actual enforcement procedures in the Member States.
Radial Field Piezoelectric Diaphragms
Authors: Bryant Robert G. , Effinger Robert T. , Aranda Isaiah , Copeland Ben M. , Covington Ed W. , Hogge Jane M.
Published: June 2004

A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes “ICE” and Interdigitated Ring Electrodes “IRE”. When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezo-ceramic along the Z-axis (perpendicular to the applied electric field). Unlike piezoelectric bender actuators, the Radial Field Diaphragm (RFD) strains concentrically yet affords high displacements without any appreciable XY-strain beyond its perimeter, as both the radial and tangential strain field approach zero at the boundary independent of actuator movement. The result is a Z-axis deflection that has a conical profile. This article covers the fabrication and characterization of these RFDs as a function of poling field strength, ceramic thickness and geometry, electrode type, line spacing, surface topography, the resulting localized strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs are the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging and a highly repeatable fabrication process that uses commodity materials.
Finite Element Modeling of Polarization Rotation Around an Elongated Elliptic Cavity
Authors: Kessler Hannes , Kamlah Marc , Balke Herbert
Published: June 2004

Electromechanical loading of piezoelectric devices with high electric field and mechanical stress concentrations near electrode and crack tips may lead to a localized inhomogeneous polarization switching response which is responsible for device degradation. We present an approximate constitutive law for polarization rotation of fully poled materials in load cases which do not initiate depolarization of the material. In other words, the local poling direction is changed but the material remains poled to saturation. The structure of the constitutive law resembles incremental plasticity theory: The “yield surface” is postulated, based on an energy criterion for 90°-switching of the randomly oriented crystallites in a material point, and the energy barrier of polarization switching corresponds to the yield stress. The constitutive model is implemented into the finite element code PSU and validated for the plane sample problem of an elongated elliptic cavity in a ferroelectric material. Some implications for crack shielding models are discussed.
The Effects of Early Prevention Programs for Families with Young Children at Risk for Physical Child Abuse and Neglect: A Meta-Analysis
Authors: Geeraert Liesl , Van den Noortgate Wim , Grietens Hans , Onghena Patrick
Published: June 2004

In this article, a meta-analysis is presented on 40 evaluation studies of early prevention programs for families with young children at risk for physical child abuse and neglect with mostly nonrandomized designs. The main aim of all programs was to prevent physical child abuse and neglect by providing early family support. For the meta-analysis, a multilevel approach was used. A significant overall positive effect was found, pointing to the potential usefulness of these programs. The study demonstrated a significant decrease in the manifestation of abusive and neglectful acts and a significant risk reduction in factors such as child functioning, parent-child interaction, parent functioning, family functioning, and context characteristics.
A Note on Anthropomorphic Architecture
Authors: Nas Peter J. M. , Brakus Chantal
Published: June 2004

This poster article highights the revival of the anthropomorphic design in modern architecture by presenting two striking examples.
Symbolic Competencies for Developmental Transitions: the Case of the Choice of First Names
Authors: Zittoun Tania
Published: June 2004

Human life consists of stability interspersed with ruptures. Transitions that follow such ruptures, offer a window on processes of change at the level of skill acquisition, identities, but also meaning construction. The article explores various uses of cultural elements such as books, movies or religious baggage as symbolic resources for such psychological development. It introduces the notion of interiority to have access to the work of these symbolic resources on emotions. Such uses of symbolic resources are examined through a study of the procedure of choosing first names during the transition to parenthood. The notion of symbolic competencies, as the abilities to use cultural elements as resources for thinking, action and development, is proposed to account for interpersonal differences and is discussed.
Circulating Aboriginality
Authors: Townsend-Gault Charlotte
Published: June 2004

First Nations designs and motifs derived from crest imagery have proliferated over the last two decades in urban British Columbia. Their circulation through public and private spaces is, however, subject to limitations, variously perceptible. The notion of figuration is used to consider the ways in which this material is apprehended. Non-natives through whose hands this material circulates, typically exercising what they think of as their rights to freedom of access, are led towards more intractable forms of ‘evidence’ for aboriginality. First Nations, equally implicated in its circulation, exercising their sovereign rights, monitor the ‘trivia’ in such a way that it becomes, not without an ironic readjustment of power relations, a line of defence against further encroachment. In this sense the most ephemeral, apparently valueless, items are characterized by keeping-while-giving and are declarations of the inalienable. It is suggested that inalienability derives from the idea of mutual embodiment as between humans and non-humans figured in the crests.
‘It’s not about Candy’
Authors: Baker Sarah
Published: June 2004

This article explores the musical practices of a small group of pre-teen girls in an after school care centre in Adelaide, South Australia. These practices constituted ‘serious play’ as the girls attempted to transform and reconfigure the space through their engagement with popular music. The article illustrates how the girls challenged the power relations of the institutional setting both musically and sexually. It concludes that the music that the young girls listened to and the way they played with such music were ‘not about candy’. Rather, the girls’ musical engagement in after school care was related to constantly shifting fields of power and a struggle over western cultural beliefs regarding asexual childhood.
Punishing Images
Authors: Lynch Mona
Published: June 2004

This article explores the use of web cameras inside a local penal facility in Phoenix, Arizona through which jail detainees’ daily routines were broadcast on the Internet over a two-year period. I question whether and how the logic behind broadcasting these penal images and the actual practice of capturing and distributing such images may indicate a significant change in the penal enterprise. In the end, I suggest that this phenomenon further reshapes contemporary penality into a form of visual entertainment commodity, and as such, may be converging with several other social transformations to fundamentally reconfigure the penal subject.
‘Looking Death in the Face’
Authors: Girling Evi
Published: June 2004

This article focuses on the controversial ‘We on death row’ campaign launched by Benetton in January 2000. The campaign featured photographic images of prisoners from death rows in the USA. The campaign, which has been dismissed by Austin Sarat as an old and failing abolitionist strategy, poses a number of challenges for our understanding and assessments of the potential ‘reformist’ efficacy of representations of punishment. The article sets out to explore the ways of seeing and strategies of knowing the death penalty in the USA and the contingent and unpredictable consequences of local ways of seeing and strategies of knowing of these global spectacles of punishment. It argues that despite the effectiveness of the cultural policing of representations of the death penalty in the USA the Benetton campaign allowed a ‘witnessing’, a seeing through the pretences behind the sanctioning of the death penalty at a moment which may prove resistant to the normalization of disturbing images of punishment - the liminal state of death row.
Responses of Dorsal Cochlear Nucleus Neurons to Signals in the Presence of Modulated Maskers
Authors: Neuert Veronika , Verhey Jesko L. , Winter Ian M.
Published: June 2004

The detection of a signal in noise is enhanced when the masking noise is coherently modulated over a wide range of frequencies. This phenomenon, known as comodulation masking release (CMR), has been attributed to across-channel processing; however, the relative contribution of different stages in the auditory system to such across-channel processing is unknown. It has been hypothesized that wideband or lateral inhibition may underlie a physiological correlate of CMR. To further test this hypothesis, we have measured the responses of single units from the dorsal cochlear nucleus in which wideband inhibition is particularly pronounced. Using a sinusoidally amplitude-modulated tone at the best frequency of each unit as a masker, a pure-tone signal was added in the dips of the masker modulation. Flanking bands (FBs, also amplitude-modulated pure tones) were positioned to fall within the inhibitory sidebands of the receptive field of the unit. The FBs were either in phase (comodulated) or out of phase (codeviant) with the on-frequency masker. For the majority of units, the addition of the comodulated FBs produced a strong reduction in the response to the masker modulation, making the signal more salient in the post stimulus time histograms. The change in spike rate in response to the signal between the masker and signal-plus-masker conditions was greatest for the comodulated condition for 29 of 45 units. These results are consistent with the hypothesis that wideband inhibition may play a role in across-channel processing at an early stage in the auditory pathway.
Consolidation of Fear Extinction Requires Protein Synthesis in the Medial Prefrontal Cortex
Authors: Santini Edwin , Ge Hong , Ren Keqin , de Ortiz Sandra Peña , Quirk Gregory J.
Published: June 2004

Extinction of conditioned fear is thought to form a long-term memory of safety, but the neural mechanisms are poorly understood. Consolidation of extinction learning in other paradigms requires protein synthesis, but the involvement of protein synthesis in extinction of conditioned fear remains unclear. Here, we show that rats infused intraventricularly with the protein synthesis inhibitor anisomycin extinguished normally within a session but were unable to recall extinction the following day. Anisomycin-treated rats showed no savings in the rate of re-learning of extinction, consistent with amnesia for extinction training. The identical effect was observed when anisomycin was microinfused into the medial prefrontal cortex (mPFC) but not the insular cortex. Furthermore, we observed that extinction training increased c-Fos levels in the mPFC but not in the insular cortex, consistent with extinction-induced gene expression in the mPFC. These findings extend previous lesion and unit-recording data by demonstrating that the mPFC is a critical storage site for extinction memory, rather than simply a pathway for expression of extinction. Understanding consolidation of fear extinction could lead to new treatments for anxiety disorders in which fear extinction is thought to be compromised.
Oculomotor Areas of the Primate Frontal Lobes: A Transneuronal Transfer of Rabies Virus and [14C]-2-Deoxyglucose Functional Imaging Study
Authors: Moschovakis A. K. , Gregoriou G. G. , Ugolini G. , Doldan M. , Graf W. , Guldin W. , Hadjidimitrakis K. , Savaki H. E.
Published: June 2004

We used the [14C]-2-deoxyglucose method to study the location and extent of primate frontal lobe areas activated for saccades and fixation and the retrograde transneuronal transfer of rabies virus to determine whether these regions are oligosynaptically connected with extraocular motoneurons. Fixation-related increases of local cerebral glucose utilization (LCGU) values were found around the fundus of the inferior limb of the arcuate sulcus (AS) just ventral to its genu, in the dorsomedial frontal cortex (DMFC), cingulate cortex, and orbitofrontal cortex. Significant increases of LCGU values were found in and around both banks of the AS, DMFC, and caudal principal, cingulate, and orbitofrontal cortices of monkeys executing visually guided saccades. All of these areas are oligosynaptically connected to extraocular motoneurons, as shown by the presence of retrogradely transneuronally labeled cells after injection of rabies virus in the lateral rectus muscle. Our data demonstrate that the arcuate oculomotor cortex occupies a region considerably larger than the classic, electrical stimulation-defined, frontal eye field. Besides a large part of the anterior bank of the AS, it includes the caudal prearcuate convexity and part of the premotor cortex in the posterior bank of the AS. They also demonstrate that the oculomotor DMFC occupies a small area straddling the ridge of the brain medial to the superior ramus of the AS. Our results support the notion that a network of several interconnected frontal lobe regions is activated during rapid, visually guided eye movements and that their output is conveyed in parallel to subcortical structures projecting to extraocular motoneurons.
Axonal Growth Is Sensitive to the Levels of Katanin, a Protein That Severs Microtubules
Authors: Karabay Arzu , Yu Wenqian , Solowska Joanna M. , Baird Douglas H. , Baas Peter W.
Published: June 2004

Katanin is a heterodimeric enzyme that severs microtubules from the centrosome so that they can move into the axon. Katanin is broadly distributed in the neuron, and therefore presumably also severs microtubules elsewhere. Such severing would generate multiple short microtubules from longer microtubules, resulting in more microtubule ends available for assembly and interaction with other structures. In addition, shorter microtubules are thought to move more rapidly and undergo organizational changes more readily than longer microtubules. In dividing cells, the levels of P60-katanin (the subunit with severing properties) increase as the cell transitions from interphase to mitosis. This suggests that katanin is regulated in part by its absolute levels, given that katanin activity is high during mitosis. In the rodent brain, neurons vary significantly in katanin levels, depending on their developmental stage. Levels are high during rapid phases of axonal growth but diminish as axons reach their targets. Similarly, in neuronal cultures, katanin levels are high when axons are allowed to grow avidly but drop when the axons are presented with target cells that cause them to stop growing. Expression of a dominant-negative P60-katanin construct in cultured neurons inhibits microtubule severing and is deleterious to axonal growth. Overexpression of wild-type P60-katanin results in excess microtubule severing and is also deleterious to axonal growth, but this only occurs in some neurons. Other neurons are relatively unaffected by overexpression. Collectively, these observations indicate that axonal growth is sensitive to the levels of P60-katanin, but that other factors contribute to modulating this sensitivity.
Rewarding Effects of AMPA Administration into the Supramammillary or Posterior Hypothalamic Nuclei But Not the Ventral Tegmental Area
Authors: Ikemoto Satoshi , Witkin Brian M. , Zangen Abraham , Wise Roy A.
Published: June 2004

We examined whether injections of the excitatory amino acid AMPA are rewarding when injected into the posterior hypothalamus and ventral tegmental area. Rats quickly learned to lever-press for infusions of AMPA into the supramammillary or posterior hypothalamic nuclei but failed to learn to lever-press for similar injections into the ventral tegmental areas. AMPA injections into the supramammillary nucleus, but not the ventral tegmental area, induced conditioned place preference. The rewarding effects of AMPA appear to be mediated by AMPA receptors, because coadministration of the AMPA antagonist CNQX blocked the rewarding effects of AMPA, and administration of the enantiomerR-AMPA did not mimic the rewarding effects. AMPA injections into the supramammillary nucleus, but not the ventral tegmental area, also increased extracellular dopamine concentrations in the nucleus accumbens. Pretreatment with the D1dopamine antagonist SCH 23390 [R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine] led to extinction of AMPA self-administration. These findings implicate posterior hypothalamic regions in reward function and suggest that reward mechanisms localized around the ventral tegmental area are more complex than has been assumed recently.
Modellierung, Simulation und Produktionsplanung von rohrlosen Anlagen (Modelling, Simulation and Production Planning of Pipeless Plants)
Authors: Liefeldt Andreas , Engell Sebastian
Published: June 2004

Bei der Herstellung von Life-Science Produkten wird die Fähigkeit, schnell auf sich ändernde Marktanforderungen reagieren zu können, zunehmend zu einem Schlüsselfaktor des wirtschaftlichen Erfolgs. Rohrleitungslose Anlagen stellen eine flexiblere Alternative zu Standard-Mehrproduktanlagen dar, bei denen die Planung und der Betrieb effektiv durch den Einsatz von Simulations- bzw. Optimierungssoftware unterstützt werden kann. PPSiM ist eine graphische Softwareumgebung, die auf die spezifischen Charakteristika von Pipeless Plants zugeschnitten ist und dem Planer oder Betreiber im Bereich Design, Layout und Scheduling Entscheidungshilfen bietet.
Model‐reference adaptive and self‐tuning controls of telescopic mobile cranes with the impact of elastic cables, viscoelastic cylinders, and winds
Authors: Tuan Le Anh
Published: February 2024

Telescopic truck crane is an under‐actuated mechanical system with three actuators controlling five outputs. Its complex structure, shape variation, uncertain parameters, elastic cables, and viscoelastic cylinders are great challenges in control design. This article proposes two adaptive robust controllers for such cranes. A control core assures robustness based on back‐stepping and Lyapunov stability. The adaptation is achieved by employing model‐reference adaptive and self‐tuning control approaches. Thus, the benefits of these adaptive techniques are introduced into the control systems. The application to a practical crane shows the effectiveness of the proposed controllers. The crane has robustness and adaptation despite the elasticity and friction of the load‐carrying cable, the viscoelasticity of the cylinders, the variation of crane parameters, and the presence of winds. Comprehensive comparison indicates the state of the art and the shortcomings of the control systems.
Simultaneous Improvement of the Strength and Plasticity for Ti‐Reinforced Fine‐Grained Magnesium Matrix Composites Prepared by Powder Metallurgy
Authors: Xu Yan , Meng Dawei , Cheng Yuanyuan , Jia Jianbo , Yan Zewen , Zhang Jie
Published: February 2024

Ti‐reinforced AZ61 magnesium matrix composites, demonstrating enhanced strength and plasticity, are synthesized via powder metallurgy method, including mechanical milling and spark plasma sintering. This study investigates the evolution of microstructure and compressive mechanical properties of Ti/AZ61 composites across various Ti weight percentages: 0%, 5%, 10%, 15%, and 20%. The composites at 5, 10, 15, and 20 wt% Ti concentrations are effectively compacted, achieving relative densities of 99.1%, 99.4%, 98.7%, and 98.6%, respectively. The integration of Ti particles facilitates a refinement of the Mg grain size. The average Mg grain size in the AZ61 alloy is refined from 8.7 ± 3.6 to 7.2 ± 4.5 μm and 4.4 ± 2.2 μm upon the addition of 5 and 10 wt% Ti particles. Conversely, incremental Ti concentrations of 15 and 20 wt% result in minor increases in the average Mg grain size to 5.3 ± 2.6 and 5.7 ± 3.2 μm, respectively. Interfacial compounds, notably Al3Ti, are identified. Compressive mechanical properties, including compressive yield stress (CYS), ultimate compressive stress (UCS), and compressive failure strain (CFS), are synergistically enhanced with Ti particle incorporation. Optimal mechanical properties, specifically CYS at 250 MPa, UCS at 502 MPa, and CFS at 13%, are observed in the 10 wt% Ti/AZ61 composite. The enhanced compressive behavior is attributed to strong interfacial bonding between deformable Ti and Mg, effective load transfer, and grain refinement. Additional contributing factors include variations in the elastic modulus and thermal expansion coefficients between Ti and Mg. The fracture mechanisms observed in the Ti/AZ61 composites involve both ductile and brittle modes of failure.
From Short Circuit to Completed Circuit: Conductive Hydrogel Facilitating Oral Wound Healing
Authors: Zhou Qiangqiang , Dai Hanqing , Yan Yukun , Qin Zhiming , Zhou Mengqi , Zhang Wanlu , Zhang Guoqi , Guo Ruiqian , Wei Xiaoling
Published: February 2024

The primary challenges posed by oral mucosal diseases are their high incidence and the difficulty in managing symptoms. Inspired by the ability of bioelectricity to activate cells, accelerate metabolism, and enhance immunity, a conductive polyacrylamide/sodium alginate crosslinked hydrogel composite containing reduced graphene oxide (PAA‐SA@rGO) is developed. This composite possesses antibacterial, anti‐inflammatory, and antioxidant properties, serving as a bridge to turn the “short circuit” of the injured site into a “completed circuit,” thereby prompting fibroblasts in proximity to the wound site to secrete growth factors and expedite tissue regeneration. Simultaneously, the PAA‐SA@rGO hydrogel effectively seals wounds to form a barrier, exhibits antibacterial and anti‐inflammatory properties, and prevents foreign bacterial invasion. As the electric field of the wound is rebuilt and repaired by the PAA‐SA@rGO hydrogel, a 5 × 5 mm2 wound in the full‐thickness buccal mucosa of rats can be expeditiously mended within mere 7 days. The theoretical calculations indicate that the PAA‐SA@rGO hydrogel can aggregate and express SOX2, PITX1, and PITX2 at the wound site, which has a promoting effect on rapid wound healing. Importantly, this PAA‐SA@rGO hydrogel has a fast curative effect and only needs to be applied for the first three days, which significantly improves patient satisfaction during treatment.
Efferocytosis‐Inspired Biomimetic Nanoplatform for Targeted Acute Lung Injury Therapy
Authors: Huang Zhiwei , Li Xinze , Yu Dedong , Wang Hengcai , Chun Changju , Zhao Yingzheng
Published: February 2024

Acute lung injury (ALI) is a serious inflammatory disease that causes impairment of pulmonary function. Phenotypic modulation of macrophage in the lung using fibroblast growth factor 21 (FGF21) may be a potential strategy to alleviate lung inflammation. Consequently, achieving specific delivery of FGF21 to the inflamed lung and subsequent efficient FGF21 internalization by macrophages within the lung becomes critical for effective ALI treatment. Here, an apoptotic cell membrane‐coated zirconium‐based metal‐organic framework UiO‐66 is reported for precise pulmonary delivery of FGF21 (ACM@U‐FGF21) whose design is inspired by the process of efferocytosis. ACM@U‐FGF21 with apoptotic signals is recognized and internalized by phagocytes in the blood and macrophages in the lung, and then the intracellular ACM@U‐FGF21 can inhibit the excessive secretion of pro‐inflammatory cytokines by these cells to relieve the inflammation. Utilizing the homologous targeting properties inherited from the source cells and the spontaneous recruitment of immune cells to inflammatory sites, ACM@U‐FGF21 can accumulate preferentially in the lung after injection. The results prove that ACM@U‐FGF21 effectively reduces inflammatory damage to the lung by modulating lung macrophage polarization and suppressing the excessive secretion of pro‐inflammatory cytokines by activated immune cells. This study demonstrates the usefulness of efferocytosis‐inspired ACM@U‐FGF21 in the treatment of ALI.
Kinetically Controlled Synthesis of Metallic Glass Nanoparticles with Expanded Composition Space
Authors: Deng Bing , Wang Zhe , Choi Chi Hun , Li Gang , Yuan Zhe , Chen Jinhang , Luong Duy Xuan , Eddy Lucas , Shin Bongki , Lathem Alexander , Chen Weiyin , Cheng Yi , Xu Shichen , Liu Qiming , Han Yimo , Yakobson Boris I. , Zhao Yufeng , Tour James M.
Published: February 2024

Nanoscale metallic glasses offer opportunities for investigating fundamental properties of amorphous solids and technological applications in biomedicine, microengineering, and catalysis. However, their top‐down fabrication is limited by bulk counterpart availability, and bottom‐up synthesis remains underexplored due to strict formation conditions. Here, a kinetically controlled flash carbothermic reaction is developed, featuring ultrafast heating (>105 K s−1) and cooling rates (>104 K s−1), for synthesizing metallic glass nanoparticles within milliseconds. Nine compositional permutations of noble metals, base metals, and metalloid (M1─M2─P, M1 = Pt/Pd, M2 = Cu/Ni/Fe/Co/Sn) are synthesized with widely tunable particle sizes and substrates. Through combinatorial development, a substantially expanded composition space for nanoscale metallic glass is discovered compared to bulk counterpart, revealing that the nanosize effect enhances glass forming ability. Leveraging this, several nanoscale metallic glasses are synthesized with composition that have never, to the knowledge, been synthesized in bulk. The metallic glass nanoparticles exhibit high activity in heterogeneous catalysis, outperforming crystalline metal alloy nanoparticles.
A Fluoride‐Rich Solid‐Like Electrolyte Stabilizing Lithium Metal Batteries
Authors: Wang Huashan , Huang Weiyuan , Rao Ruijun , Zhu Jiacheng , Chen Huige , Liu Haoyu , Li Jiashuai , Li Qiufen , Bai Mengxi , Wang Xiang , Wang Xuefeng , Liu Tongchao , Amine Khalil , Wang Ziqi
Published: February 2024

To address the problems associated with Li metal anodes, a fluoride‐rich solid‐like electrolyte (SLE) that combines the benefits of solid‐state and liquid electrolytes is presented. Its unique triflate‐group‐enhanced frame channels facilitate the formation of a functional inorganic‐rich solid electrolyte interphase (SEI), which not only improves the reversibility and interfacial charge transfer of Li anodes but also ensures uniform and compact Li deposition. Furthermore, these triflate groups contribute to the decoupling of Li+ and provide hopping sites for rapid Li+ transport, enabling a high room‐temperature ionic conductivity of 1.1 mS cm−1 and a low activation energy of 0.17 eV, making it comparable to conventional liquid electrolytes. Consequently, Li symmetric cells using such SLE achieve extremely stable plating/stripping cycling over 3500 h at 0.5 mA cm−2 and support a high critical current up to 2 mA cm−2. The assembled Li||LiFePO4 solid‐like batteries exhibit exceptional cyclability for over 1 year and a half, even outperforming liquid cells. Additionally, high‐voltage cylindrical cells and high‐capacity pouch cells are demonstrated, corroborating much simpler processibility in battery assembly compared to all‐solid‐state batteries.