bluuebunny/crossref_metadata_2025 huggingface dataset:
Agent-Based Flow Control for HLA Components
Authors: Zhao Zhiming , van Albada Dick , Sloot Peter
Published: September 2005

Human-in-the-loop simulation systems, also called interactive simulation systems (ISSs), play an increasingly important role in problem-solving environments for complex problems. The High Level Architecture (HLA) provides a uniform interface for realizing the interoperability between distributed modules and has been widely applied in the construction of ISSs. However, using the current architecture, control of the simulation logic and activity flows is often fused with interconnection details, and the constituent components of an ISS have limited adaptability for other applications for which they would, in principle, be suited. An agent-based architecture, named the Interactive Simulation System Conductor (ISS-Conductor), is developed on top of the HLA. It provides a separate layer for describing, interpreting, and controlling activity flow between the HLA components. Using the ISS-Conductor architecture, a simulation or an interactive visualization system is encapsulated as a component, which contains an agent for invoking the simulation and visualization activities and an agent for controlling the runtime behavior.
Distributed Modeling Architecture of a Multi-Agent-Based Behavioral Economic Landscape (MABEL) Model
Authors: Lei Zhen , Pijanowski Bryan C. , Alexandridis Konstantinos T. , Olson Jennifer
Published: September 2005

The authors discuss a distributed modeling architecture in a multi-agent-based behavioral economic landscape (MABEL) model that simulates land-use changes over time and space. Based on agent-based modeling methodologies, MABEL presents a bottom-up approach to allow the analysis of dynamic features and relations among geographic, environmental, human, and socioeconomic attributes of landowners, as well as comprehensive relational schematics of land-use change. The authors adopt a distributed modeling architecture (DMA) in MABEL to separate the modeling of agent behaviors in Bayesian belief networks from task-specific simulation scenarios.Through a client-server infrastructure, MABEL provides an efficient and scalable decision request-response mechanism among heterogeneous agents, scenarios, and behavioral models. As an important part of the land-use change model, a market-bidding system and an adaptive land partition algorithm for land transactions are also discussed.
Reliable and Enhanced Stiffness Perception in Soft-tissue Telemanipulation
Authors: De Gersem G. , Van Brussel H. , Tendick F.
Published: September 2005

Haptic feedback is one of the missing links in robotized minimally invasive telesurgery. The teleoperation controllers are optimized so as to offer the surgeon a reliable perception of the stiffness of soft tissue, rather than following the traditional approach where tracking and force reflection fidelity are considered. The experimental results show that optimization allows for better focus on the quality of the haptic information in the performance-stability trade-off. A force sensor to measure the interaction forces with the environment is found to be indispensable for high-quality touch feedback. Next to optimization for realistic feedback of the environment stiffness, in this paper we describe how to extend human perception beyond differential thresholds and thus enhance sensitivity. Experiments on a one-dimensional system demonstrate that the operator is able to discriminate tinier differences using a telemanipulation system with enhanced sensitivity than through direct manipulation.
A Foothold Selection Algorithm for Spider Robot Locomotion in Planar Tunnel Environments
Authors: Shapiro Amir , Rimon Elon , Shoval Shraga
Published: September 2005

In this paper we present an algorithm, called the partitioned cubes gaiting (PCG) algorithm, for planning the foothold positions of spider-like robots in planar tunnels bounded by piecewise linear walls. The paper focuses on three-limb robots, but the algorithm generalizes to robots with a larger number of limbs. The input to the PCG algorithm is a geometric description of the tunnel, a lower bound on the amount of friction at the contacts, as well as start and target foothold positions. Using efficient convex programming techniques, the algorithm approximates the possible foothold positions as a collection of cubes in contact configuration space (c-space). Each cube represents a contact independent set of feasible three-limb postures. A graph structure induced by the cubes has the property that its edges represent feasible motion between neighboring sets of three-limb postures. This motion is realized by lifting one limb while the other two limbs brace the robot against the tunnel walls. A shortest-path search along the graph yields a three–two–three gait pattern that moves the robot from start to target using a minimum number of foothold exchanges. In practical environments the algorithm runs in time, which is linear in the number of tunnel walls and polynomial in the degree of cube approximation of contact c-space. Simulations as well as experiments demonstrate the PCG algorithm in tunnel environments.
Cedric Robinson’s anthropology of Marxism
Authors: Gordon Avery F.
Published: September 2005

In meditating on the significance of Robinson’s body of work, particularly An Anthropology of Marxism, Gordon discusses the profound originality of his enterprise. At its heart lies a rigorous deconstruction of the terms of western civilisation which exposes the philosophical and historical compromises made by Marxism and Liberalism with the tenets of bourgeois rationality. The blindness within Marxian thought to socialist and radical traditions outside its purview, documented and analysed by Robinson, is his starting point for a broader and more generous historical materialism that recuperates a fuller range of human experience.
Geniuses of resistance: feminist consciousness and the Black radical tradition
Authors: Quan H. L. T.
Published: September 2005

This article contests the criticisms of Black Marxism, asa basically masculinist text, that have circulated mainly in oral form. Based in part on an interview with Robinson, the article explores the concept of a closed, top-down narrative, which permits no further engagement or activity on the part of the reader, and an open-ended text, based on a methodology such as Robinson’s, which can act as a point of departure for other activist scholars. The article develops the notion of resistance itself as gendered, which is particularly evident in Robinson’s later work, and argues that the simplistic inclusion of women does not, of itself, render a text feminist.
Racially subordinate labour within global contexts: Robinson and Hopkins re-examined
Authors: Santiago-Valles Kelvin
Published: September 2005

World-systems theory has recognised that local histories of how labour has been configured in particular (racialised) contexts cannot grasp the ways in which these histories form part of the capitalist world-system. But, in pursuing world-historical analyses of racially subordinate labour, there is also a danger of ignoring what is historically specific about such labour. Focusing on the affinities between Cedric Robinson’s work, particularly in Black Marxism, and that of Terence K. Hopkins in the late 1970s and early 1980s points to ways in which this challenge can be overcome.
Twenty-five years of the Third World News Review
Authors: Robinson Elizabeth
Published: September 2005

In an age of disinformation, where media power is not only concentrated in fewer and fewer hands, but is exercised with increasing disregard for truth, the role of small, community-based alternative broadcasters becomes ever more crucial. This article examines the experience, over twenty-five years, of running a regular programme on the Third World. Initially set up by Cedric Robinson and Corey Dubin, using volunteer journalists and information gatherers, the Third World News Review is not only a significant source of real information for a wider community but an example that could be followed elsewhere.
Writing in solidarity: the new generation
Authors: Herard Tiffany
Published: September 2005

How can we build a new generation of radical scholars to survive the new world order? How, practically, can such scholars participate in, sustain and recreate the Black radical tradition for the future? The November 2004 Symposium on Cedric Robinson’s Radical Thought was one such initiative, which, both in its intent and its format, subverted the standard mode of the academic conference. Drawing on her experience as one of its organisers, the author reflects more deeply on the nature of academic life and its tendency to isolationism, the specific challenges it poses to radical women academics of colour and the need to develop ongoing, collaborative writing and scholarship.
Personality Disorder and Homelessness: Membership and ‘Unhoused Minds’ in Forensic Settings
Authors: Adlam John , Scanlon Christopher
Published: September 2005

Although not all homeless people are personality disordered, many are offenders and all are de facto anti-social, either in their orientation to the world or in the eyes of the beholding world. We re-define and re-locate the problem from the social fact of the actual homelessness into the interpersonal and intrapsychic world of the ‘unhoused mind’, and explore the complex reciprocal relationship between the housed and the unhoused. The article concludes by discussing the impact on individual workers, staff teams and organizations who are tasked with attempting to help such people.
Moving On: A Group for Patients Leaving a High Security Hospital
Authors: Adshead Gwen , Charles Sharmila , Pyszora Natalie
Published: September 2005

In this paper, the authors describe the work of a group set up for those patients who are leaving a high security forensic psychiatric hospital, all having been detained under the 1983 Mental Health Act for England and Wales. Background information on the hospital is presented, as well as an overall view of the patients and their problems. The origins of the group are documented, followed with examples of group dynamics peculiar to the practice of forensic psychotherapy and conscious and unconscious anxieties on the part of the therapists as well as the patients.
Finding the Abuser in the Victim
Authors: Woods John
Published: September 2005

A period of transition in the life of a forensic outpatient group is described. Transference and countertransference issues were stirred up by the change of conductor, and related to the theme of perversion in the group. In order to preserve confidentiality, the identity of group members is disguised. Their contributions to the group have been combined and changed in order not to represent individuals but to convey the essence of the group process.
Forensic Psychotherapy for Adults with Learning Disabilities: An Inpatient Group-Analytic Group
Authors: Xenitidis Kiriakos I. , Barnes Jane , White Jeremy
Published: September 2005

People with learning disabilities are at high risk of behavioural problems, including offending behaviours. Psychoanalytically based forensic psychotherapy is a recognized therapeutic option for offenders without disabilities. However, its application to people with learning disabilities who offend or are at risk of offending has largely been neglected. In this paper, after clarifying the concept of learning disability we look at its traditional neglect by psychoanalysis. Subsequently we describe important clinical characteristics associated with learning disabilities and offending with specific reference to group-analytic theory. Finally we offer a clinical illustration by briefly describing the assembling and conducting of a forensic psychotherapy group along group-analytic lines before reaching some important conclusions.
Psychodrama: Working Through Action: ‘My Thank You is for Your Concern’
Authors: Jefferies Jinnie
Published: September 2005

The debate on what can be effectively done to reduce crime, protect members of the public and lower recidivist rates continues in many quarters. As a result there are now several behaviour programmes delivered by the Home Office. In this article I intend to discuss psychodrama as a treatment approach that has been used for the past 20 years at H.M.P. Grendon Underwood and how its application can change the disruptive internal worlds of those who offend.
Breaking Down the Walls: Group Analysis in a Prison
Authors: Wilson Peter T.
Published: September 2005

Prisons serve to rescue us from the real need to think about the causes and effects of criminality including our shared responsibility for understanding destructiveness. The reluctance to think and share is mirrored in the structure of prison life and in the individual(ized) psyches of criminals. Group analysis with its emphasis on the matrix, ego training in action and power relations, offers the best opportunity to address these issues.
Isolation and Characterization of Wear Debris Generated in Patients Wearing Polyethylene Hylamer Inserts, Gamma Irradiated in Air
Authors: Visentin M. , Stea S. , Squarzoni S. , Reggiani M. , Fagnano C. , Antonietti B. , Toni A.
Published: September 2005

Hylamer polyethylene was used in the early 1990s to make hip-joint components. Clinical experience has shown that these components, if sterilized by gamma rays in the presence of oxygen, are easily affected by wear, which then leads to osteolysis. The authors analyzed polyethylene wear particles in seven patients who had received Hylamer polyethylene implants sterilized by gamma rays in air and had suffered prosthetic loosening. The results were compared to those of six controls, who had received traditional polyethylene implants, sterilized by the same method. The frequency distribution of globular and fibrillar particles was similar in both groups (38.5% in Hylamer, 45.2% in controls). The globular particles in the Hylamer samples had a mean area of 0.12 mm2, which was significantly lesser than that of the controls (0.30 mm2). The width of fibrillar particles in the Hylamer samples was significantly lesser than that of the controls. Therefore, the two materials, despite undergoing the same type of sterilization, produced different types of wear, due to their different properties. In conclusion, the difference in the morphology of Hylamer polyethylene wear particles in comparison with PCA might have caused a more intensive biological response, early and massive osteolysis, and therefore, early loosening.
Swellable Coatings for Hearing Aid Applications
Authors: Choi Sung-Il , Christensen M. B. , Fredin N. , Pitt W. G.
Published: September 2005

The problem of acoustic feedback in hearing aids could be solved potentially by applying a compliant hydrogel to the outer surface that would conform to the ear canal and block feedback. With this objective, several formulations of hydrogels were developed and their swelling and mechanical properties investigated. Hydrogel formulations were polymerized from hydroxyethyl methacrylate (HEMA) and N-vinyl-pyrrolidone (NVP), with various photo-initiators, crosslinkers, and swelling agents. The hydrogel that swelled most rapidly and yet remained undissolved in water had a monomer composition of 40 mol% HEMA, 60 mol% NVP, with 1 wt% polyethylene glycol dimethacrylate as a crosslinker, and 0.5 wt% 2,2-dimethoxy-2-phenyl-acetophenone as the photo-initiator. The tensile modulus, strength, hardness, and durability of the dry hydrogels were not a strong function of composition. In the swollen state, the mechanical properties were much reduced. The potential use of these materials on hearing aids has been discussed in this article.
Fabrication, Characterization, and in vitro Degradation of Composite Scaffolds Based on PHBV and Bioactive Glass
Authors: Li Haiyan , Du Ruilin , Chang Jiang
Published: September 2005

Composite scaffolds of polyhydroxybutyrate-polyhydroxyvalerate (PHBV) with sol-gel-derived bioactive glass (BG, 58S) are fabricated by compression molding, thermal processing, and salt particulate leaching method. Structure and mechanical properties of the scaffolds are determined. The bioactivity of the composites is evaluated by soaking the scaffolds in a simulated body fluid (SBF), and the formation of the apatite layer on the scaffolds is determined by scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). The results show that the PHBV/BG composites are bioactive as they induce the formation of apatite on the composite scaffolds after soaking in SBF for 3 days. In addition, the measurements of the water contact angles suggest that incorporation of BG into PHBV can improve the hydrophilicity of the composites and the enhancement is dependent on the BG content. Furthermore, the degradation assessment of the scaffolds is performed in phosphate-buffered saline (PBS) solution at 37 C. Weight loss and water absorption of the scaffolds, pH of the incubation media, and molecular weight measurements of the PHBV in the scaffolds are used to monitor the degradation of the scaffolds during a nine-week incubation in PBS. It has been found that the incorporation of bioactive glass into the PHBV delayed the degradation of PHBV in the composite scaffolds for the period investigated. The present results show not only a useful method to prepare composite scaffolds with improved properties but also a way of adjusting the in vitro degradation behavior of composite scaffolds by tailoring the content of bioactive glass.
Repair of Bone Tissue Affected by Osteoporosis with Hydroxyapatite-Poly-L-lactide (HAp-PLLA) With and Without Blood Plasma
Authors: Ajduković Z. , Najman S. , Ðorđević Lj , Savić V. , Mihailović D. , Petrović D. , Ignjatović N. , Uskoković D.
Published: September 2005

The aim of this study is to examine the reparatory ability of the synthetic biomaterial hydroxyapatite-poly-L-lactide (HAp-PLLA), the replacement of alveolar ridge, and rehabilitation of bone defects caused by osteoporosis, in an experimental group of animals. The experiments are performed on syngeneic Sprague Dawley rats. Osteoporosis is induced by glucocorticoids in rats during a 12-week period. After this, the experimental group of animals is divided into five subgroups. An artificial defect is made in the alveolar bone on the left side of the mandible. In one group of animals, the defect is left to heal by itself, while in other groups, pure HAp-PLLA or one mixed with plasma is implanted. The best results are achieved by the implantation of the HAp-PLLA composite biomaterial mixed with autologous plasma. Formation of a new mandibular bone is seen, growing intensely, leading to rapid osteogenesis.
Leisure role of public libraries
Authors: Hayes Emma , Morris Anne
Published: September 2005

This is the second of two articles examining the leisure role of public libraries. The first article examined the leisure role of public libraries in the UK from a historical perspective. This examines the value of the public library service in providing leisure opportunities from a user point of view. The results demonstrate that public libraries have a significant impact on people’s leisure time. Benefits include providing relaxation, improving health and well-being, opening up choices and opportunities despite financial constraints, alleviating boredom and allowing people to socialize. Public libraries are, therefore, providing a worthwhile and necessary function through their leisure role.
Editorial
Authors: Jones-Evans Angela
Published: September 2005

Discusses the consultation document about the restructuring of library services at University of Wales Bangor which proposed the cutting of eight librarian positions. Gives an overview of a paper compiled by a group set up within the library service to formulate a response to the consultation document. Suggests alternatives to the proposed redundancies including adoption of a matrix-style team approach and a flat organizational structure. Argues that subject specialists and information professionals are more necessary than ever in an era of increasingly complex electronic resources.
Self-organization in a Simple Task of Motor Control Based on Spatial Encoding
Authors: Linder Christian R.
Published: September 2005

This paper elaborates on the possibilities for self-adjustment of a biological neural network used as feedback controller in the motor control system of a six-legged walker. As biological systems, in contrast to technical systems, show an impressive capability of self-adaptation, this is meant as a proof of principle. Complementing an intensity encoded system (Linder, 2002), where scalar values are represented as the activity of a given neuron, this mechanism is based on spatial encoding, where a scalar value is represented as the location of the most active neuron in a chain of neurons. This encoding scheme can often be observed in biological systems. While the intensity encoded system requires linear input characteristics and symmetrical distribution of the input values over the whole range for both target angles and actual angles, the spatially encoded system presented here is completely self-organizing for evenly distributed target angles and actual angles. By employing an internal teaching signal, it can even adjust for arbitrary (i.e., biologically relevant) distributions of the input. This internal signal is provided through body geometry. Instead of error back-propagation, the system exploits local neuronal mechanisms implicated by a biologically plausible realization of self-organizing maps.
Incremental Development of Adaptive Behaviors using Trees of Self-Contained Solutions
Authors: Dahl Torbjørn Semb , Giraud-Carrier Christophe
Published: September 2005

We present a methodology for incremental development of complex adaptive behaviors in robots. The methodology decomposes a given root strategy into a tree of self-contained supporting strategies that can be fully implemented and tested before the next strategy is added. The methodology also uses comparative performance tests for each new strategy relative to its predecessor. The methodology assumes the use of skill modules that can be shared by multiple behavioral layers and produces learning mechanisms that are highly specialized and context dependent. Two example applications of the methodology are presented using simulated robots in the domains of foraging/mapping and conflict resolution. The examples are implemented by hand using a decomposed model of behavior that allows skill modules to be shared while retaining a unique representation of each strategy for excitation and inhibition. Finally, we discuss how the solutions produced using this methodology differ from existing behavior-based solutions.
The fall and rise of cleanliness in British healthcare and the nursing contribution
Authors: Gould Dinah
Published: September 2005

This paper discusses the term ‘cleanliness’ and applies it to healthcare. Ways of achieving cleanliness in premises where healthcare is delivered are explored. It is concluded that although once a world-leader in infection control practice and research, the United Kingdom is now lagging behind other countries. Traditionally hands have been regarded as the main vectors of healthcare-associated infection. However, hands can never be rendered entirely free of micro-organisms, so it is inevitable that healthcare-associated infection will always be a challenge. Decontamination of the healthcare environment, its fixtures, fittings and clinical equipment are also of pivotal importance in maintaining cleanliness, controlling infection and regaining consumer confidence in healthcare. Nurses play a major role in ensuring that appropriate decontamination processes and procedures are in place to meet required standards. To do so they must receive the appropriate education and training.
Commuters' Exposure to Carbon Monoxide and Carbon Dioxide in Air-conditioned Buses in Hong Kong
Authors: Chan M. Y.
Published: September 2005

The summer in Hong Kong is hot and humid with temperatures over 30°C and relative humidity over 70%. Air-conditioned buses were first introduced in the early 1990s and have become more and more popular. Everyday, millions of passenger-trips are taken in such buses and the air quality and thermal environment in them has become a public health issue. One major source of pollution is the passengers themselves but re-entry of engine emission is also a concern. People have always complained about the thermal environment of the buses especially during rush hours saying they are stuffy, smelly and have inadequate fresh air. We measured conditions in air-conditioned buses and non air-conditioned buses, running on 12 different bus routes in the Hong Kong Special Administrative Region (HKSAR), in both urban and rural areas. Two trips were made for each route. Portable gas analysers measured carbon monoxide (CO), carbon dioxide (CO2), temperature and relative humidity. The measurements showed there was no evidence that CO and CO2 levels in the air-conditioned buses were statistically higher than in non air-conditioned buses ( p 0.05). For the rural commutes, the in-vehicle levels of CO and CO2 were not significantly higher than for urban commutes (p 0.05). The Environmental Protection Department (EPD), HKSAR had published a guidance note for airconditioned public transport facilities and most of the exposures found, including the thermal environment, were acceptable with regard to the recommendations in the note. Momentary high levels of CO2 were found, but this lasted for a short period only.
Monitoring of Fungi and Bacteria in the Indoor Air of Primary Schools in Edirne City, Turkey
Authors: Aydogdu Halide , Asan Ahmet , Otkun Muserref Tatman , Ture Mevlut
Published: September 2005

We monitored levels of bacteria and fungi in the indoor air at selected sites of several public primary schools in the city of Edirne, Turkey. Sampling was by the Petri plate method onto both a Rose-Bengal streptomycin agar medium and a 5% sheep-blood agar medium exposed to the air for 10-minute periods. Samples were collected monthly over a period of 6 months between August 2001 and January 2002. A total of 941 microfungi and 2066 bacterial colonies were counted on 90 Petri plates. During this 6-month period, 19 bacterial genera, 15 fungal genera and 48 species of fungi were isolated from the air in the schools. Some bacteria, such as coagulase-negative Staphylococcus, Corynebacterium and Bacillus, were predominant (42.7%, 20.4% and 6.9% of the total, respectively). Penicillium, Cladosporium and Alternaria were the most common fungal genera (42.8%, 19.3% and 10.1% of the total, respectively). Staphylococcus, Acinetobacter, Corynebacterium, Propionibacterium and Pseudomonas genera were found in every month. Statistical analysis of the data showed a positive correlation between the concentrations of bacteria and air humidity (p 0.002, R2 0.726) and between bacterial concentrations and age of the schools ( p 0.045, R2 0.787). Also, that there was seasonal variation since the concentrations of fungi and bacteria varied according to the months ( p 0.001).
Indoor Deposition and Forced Re-suspension of Respirable Particles
Authors: Miguel António F. , Aydin Murat , Reis A. Heitor
Published: September 2005

The rate at which particles deposit and re-suspend from indoor surfaces is an essential parameter in determining human exposure to aerosol particles. In this study, we investigate experimentally particle deposition and forced re-suspension in a cubical enclosure for three particle sizes (0.7, 1.5 and 4 m).

For particle deposition, the results are presented in terms of particle deposition velocity. It was observed that the particle deposition velocity is particularly significant for the floor surface. Deposition on vertical and ceiling surfaces becomes important only when these surfaces are electrically charged. Air humidity did not influence the particle deposition apart from when it was close to saturation.

Re-suspension of particles from the floor surface due to household activities was also studied. It was observed that small particles are more difficult to detach from the floor than bigger ones. Besides, there is a pressure above which re-suspension is very likely to occur (minimum re-suspension pressure). This minimum pressure is dependent on the particle size.
Poverty Relief, Global Institutions, and the Problem of Compliance
Authors: Fuller Lisa
Published: September 2005

Thomas Pogge and Andrew Kuper suggest that we should promote an ‘institutional’ solution to global poverty. They advocate the institutional solution because they think that non-governmental organizations (NGOs) can never be the primary agents of justice in the long run. They provide several standard criticisms of NGO aid in support of this claim. However, there is a more serious problem for institutional solutions: how to generate enough goodwill among rich nation-states that they would be willing to commit themselves to supranational institutional reforms. In the current international political climate, the implementation of such institutional reforms introduces several intractable problems, including difficulties of global coordination and enforcement. I defend the solution of NGO aid from the criticisms presented by Pogge and Kuper, and propose how it might be reformed. My main suggestion is that all practising NGOs should be required to be ‘accountable for reasonableness’ in the sense that Norman Daniels and James Sabin have outlined.
Thomas Pogge’s Global Resources Dividend: A Critique and an Alternative
Authors: Hayward Tim
Published: September 2005

Pogge’s proposal for a Global Resources Dividend (GRD) has been criticized because its likely effects would be less predictable than Pogge supposes and could even be counterproductive to the main aim of relieving poverty. The GRD might also achieve little with respect to its secondary aim of promoting environmental protection. This article traces the problems to Pogge’s inadequate conception of natural resources. It proposes instead to conceive of natural resources in terms of ‘ecological space’. Using this conception, redistributive principles follow with a more definite logic from Pogge’s own supporting moral argument. The proposed alternative approach also promises a more direct contribution to Pogge’s secondary aim of resource conservation and environmental protection. I conclude that if any redistributive resource-based tax should be levied on nations, then there are at least four decisive reasons to favour levying a tax related to a nation’s per capita utilization of ecological space rather than the GRD.
Poverty and the Moral Significance of Contribution
Authors: Øverland Gerhard
Published: September 2005

The main thesis of the article is that one’s responsibility to render assistance is not affected by having contributed to the situation by causing harm. I examine ways in which contribution to need is morally significant. Although contribution is relevant with regard to certain features, such as questions of blame, compensation, and fair distribution of the cost of assistance, I argue that contribution should carry no weight when assessing our duty to assist people in severe need if we can do so at little cost. If this is true we have reason to suspect that it is redundant to know whether or not we have in fact contributed to the need of the global poor when assessing our duty to address global poverty.
Alkylamines cause Vγ9Vδ2 T-cell activation and proliferation by inhibiting the mevalonate pathway
Authors: Thompson Keith , Rojas-Navea Javier , Rogers Michael J.
Published: September 2005

Three general classes of small, nonpeptide “antigens” activate Vγ9Vδ2 T cells: pyrophosphomonoesters, such as isopentenyl diphosphate (IPP), nitrogen-containing bisphosphonates (N-BPs), and alkylamines. However, we have shown recently that N-BPs indirectly activate Vγ9Vδ2 T cells as a consequence of inhibition of farnesyl diphosphate synthase (a key enzyme of the mevalonate pathway) and the intracellular accumulation of IPP. We now show that alkylamines activate Vγ9Vδ2 T cells by the same mechanism. Alkylamines were found to be weak inhibitors of farnesyl diphosphate synthase and caused accumulation of unprenylated Rap1A in peripheral blood mononuclear cells and macrophages, indicative of inhibition of the mevalonate pathway. Furthermore, as with N-BPs, the stimulatory effect of the alkylamines on Vγ9Vδ2T cells was abrogated by simultaneous treatment with mevastatin. These findings suggest that only pyrophosphomonoesters such as IPP are true Vγ9Vδ2 T-cell agonists, whereas alkylamines and N-BPs indirectly activate Vγ9Vδ2 T cells through a common mechanism involving the accumulation of IPP.
The inositol phosphatase SHIP-2 down-regulates FcγR-mediated phagocytosis in murine macrophages independently of SHIP-1
Authors: Ai Jing , Maturu Amita , Johnson Wesley , Wang Yijie , Marsh Clay B. , Tridandapani Susheela
Published: September 2005

FcγR-mediated phagocytosis of IgG-coated particles is a complex process involving the activation of multiple signaling enzymes and is regulated by the inositol phosphatases PTEN (phosphatase and tensin homolog deleted on chromosome 10) and SHIP-1 (Src homology [SH2] domain-containing inositol phosphatase). In a recent study we have demonstrated that SHIP-2, an inositol phosphatase with high-level homology to SHIP-1, is involved in FcγR signaling. However, it is not known whether SHIP-2 plays a role in modulating phagocytosis. In this study we have analyzed the role of SHIP-2 in FcγR-mediated phagocytosis using independent cell models that allow for manipulation of SHIP-2 function without influencing the highly homologous SHIP-1. We present evidence that SHIP-2 translocates to the site of phagocytosis and down-regulates FcγR-mediated phagocytosis. Our data indicate that SHIP-2 must contain both the N-terminal SH2 domain and the C-terminal proline-rich domain to mediate its inhibitory effect. The effect of SHIP-2 is independent of SHIP-1, as overexpression of dominant-negative SHIP-2 in SHIP-1-deficient primary macrophages resulted in enhanced phagocytic efficiency. Likewise, specific knockdown of SHIP-2 expression using siRNA resulted in enhanced phagocytosis. Finally, analysis of the molecular mechanism of SHIP-2 down-regulation of phagocytosis revealed that SHIP-2 down-regulates upstream activation of Rac. Thus, we conclude that SHIP-2 is a novel negative regulator of FcγR-mediated phagocytosis independent of SHIP-1. (Blood. 2006;107:813-820)
Suppressor activity and potency among regulatory T cells is discriminated by functionally active CD44
Authors: Firan Mihail , Dhillon Sohita , Estess Pila , Siegelman Mark H.
Published: September 2005

CD4CD25+ regulatory T cells are fundamental to the maintenance of peripheral tolerance and have great therapeutic potential. However, efforts in this regard have been hampered by limiting cell numbers in vivo, an anergic phenotype in vitro, and a rudimentary understanding of the molecular basis for the functional state of CD4CD25+ regulatory T cells (Treg cells). Here we show heterogeneity of suppressor activity among activated CD4CD25+ Treg cells and that, within this population, the functionally active, hyaluronan-binding form of CD44 (CD44act) is strikingly correlated with superior suppressor activity. Within 16 hours after in vitro activation, CD44act can discriminate enhanced suppressive function in in vitro proliferation assays and in an in vivo bone marrow engraftment model. The expression of other surface markers and that of Foxp3 are similar irrespective of hyaluronan binding and associated degree of suppressor potency. Furthermore, CD44act is induced on resting CD4CD25+ cells in vivo by allogeneic stimulation, with similar functional consequences. These results reveal a cell-surface marker that delineates functional activity within a population of activated CD4CD25+ regulatory T cells, thereby providing a potential tool for identifying regulatory activity and enriching for maximal suppressor potency.
The leukotriene B4 lipid chemoattractant receptor BLT1 defines antigen-primed T cells in humans
Authors: Islam Sabina A. , Thomas Seddon Y. , Hess Christoph , Medoff Benjamin D. , Means Terry K. , Brander Christian , Lilly Craig M. , Tager Andrew M. , Luster Andrew D.
Published: September 2005

We have recently shown that the leukotriene B4 (LTB4)–BLT1 pathway is important in early effector T-cell recruitment in mouse models of inflammation. Here we characterize the phenotype and function of human peripheral blood BLT1+ T cells in health and illustrate their involvement in asthma and acute infection. In healthy individuals, BLT1+ T cells are a rare peripheral blood T-cell population enriched for the activation markers CD38 and HLA-DR. Compared with BLT1– T cells, a larger proportion of peripheral blood BLT1+ T cells express the effector cytokines IFNγ and IL-4 and inflammatory chemokine receptors, CCR1, CCR2, CCR6, and CXCR1. Consequently, in healthy individuals peripheral blood BLT1+ T cells are a rare antigen-primed T-cell subset with unique phenotypic, migratory, and functional properties. BLT1 expression on T cells is tightly regulated by inflammation and only transiently expressed after naive T-cell activation by dendritic cells. Although rare in the peripheral blood of healthy individuals, BLT1+ T cells are markedly increased in frequency in the peripheral blood in response to acute Epstein-Barr virus (EBV) infection and moderately increased in the airways of asymptomatic allergic asthmatics. Our studies provide novel insights into the LTB4-BLT1 lipid chemoattractant pathway in human T-cell responses, and how it may link innate and adaptive immunity.
Amplification of tumor-specific regulatory T cells following therapeutic cancer vaccines
Authors: Zhou Gang , Drake Charles G. , Levitsky Hyam I.
Published: September 2005

The fate of tumor-specific CD4+ T cells is central to the outcome of the host immune response to cancer. We show that tumor antigen recognition by a subset of CD4+ T cells led to their differentiation into cells capable of suppressing naive and Th1 effector cells. Such tumor-induced regulatory T cells (TMTregs) arose both from precommitted “natural” regulatory T cells and CD4+CD25–GITRlow precursors. Once induced, TMTregs were capable of maintaining suppressor activity long after transfer into antigen-free recipients. Suppression was mediated by GITRhigh cells residing within both CD25+ and CD25– subsets. Vaccination of the tumor-bearing host concomitantly expanded TMTregs and effector cells, but suppression was dominant, blunting the expansion of naive tumor-specific T cells and blocking the execution of effector function in vitro and in vivo. These studies illustrate the possibility that therapeutic vaccination could actually worsen host tolerance to tumor antigens and support treatment paradigms that seek to not only increase the frequency of tumor-specific T cells, but to do so in conjunction with strategies that inactivate or remove regulatory T-cell populations.
Follicular dendritic-like cells derived from human monocytes
Authors: Heinemann Dagmar EH , Peters J Hinrich
Published: September 2005

Background

Follicular dendritic cells (FDCs) play a central role in controlling B-cell response maturation, isotype switching and the maintenance of B-cell memory. These functions are based on prolonged preservation of antigen and its presentation in its native form by FDCs. However, when entrapping entire pathogens, FDCs can turn into dangerous long-term reservoirs that may preserve viruses or prions in highly infectious form.

Despite various efforts, the ontogeny of FDCs has remained elusive. They have been proposed to derive either from bone marrow stromal cells, myeloid cells or local mesenchymal precursors. Still, differentiating FDCs from their precursors in vitro may allow addressing many unsolved issues associated with the (patho-) biology of these important antigen-presenting cells. The aim of our study was to demonstrate that FDC-like cells can be deduced from monocytes, and to develop a protocol in order to quantitatively generate them in vitro.

Results

Employing highly purified human monocytes as a starter population, low concentrations of Il-4 (25 U/ml) and GM-CSF (3 U/ml) in combination with Dexamethasone (Dex) (0.5 μM) in serum-free medium trigger the differentiation into FDC-like cells. After transient de-novo membrane expression of alkaline phosphatase (AP), such cells highly up-regulate surface expression of complement receptor I (CD35). Co-expression of CD68 confirms the monocytic origin of both, APpos and CD35pos cells. The common leukocyte antigen CD45 is strongly down-regulated. Successive stimulation with TNF-α up-regulates adhesion molecules ICAM-1 (CD54) and VCAM (CD106). Importantly, both, APpos as well as APneg FDC-like cells, heterotypically cluster with and emperipolese B cells and exhibit the FDC characteristic ability to entrap functionally preserved antigen for prolonged times. Identical characteristics are found in monocytes which were highly expanded in vitro by higher doses of GM-CSF (25 U/ml) in the absence of Dex and Il-4 before employing the above differentiation cocktail.

Conclusion

In this work we provide evidence that FDC-like cells can be derived from monocytes in vitro. Monocyte-derived FDC-like cells quantitatively produced offer a broad utility covering basic research as well as clinical application.
Association between occupational exposure to mineral oil and rheumatoid arthritis: results from the Swedish EIRA case–control study
Authors: Sverdrup Berit , Källberg Henrik , Bengtsson Camilla , Lundberg Ingvar , Padyukov Leonid , Alfredsson Lars , Klareskog Lars ,   the Epidemiological Investigation of Rheumatoid Arthritis study group
Published: September 2005

The aim of the present study was to investigate the association between exposure to mineral oil and the risk of developing rheumatoid arthritis (RA), and in addition to perform a separate analysis on the major subphenotypes for the disease; namely, rheumatoid factor (RF)-positive RA, RF-negative RA, anticitrulline-positive RA and anticitrulline-negative RA, respectively. A population-based case–control study of incident cases of RA was performed among the population aged 18–70 years in a defined area of Sweden during May 1996–December 2003. A case was defined as an individual from the study base who for the first time received a diagnosis of RA according to the American College of Rheumatology criteria of 1987. Controls were randomly selected from the study base with consideration taken for age, gender and residential area. Cases (n = 1,419) and controls (n = 1,674) answered an extensive questionnaire regarding lifestyle factors and occupational exposures, including different types of mineral oils. Sera from cases and controls were investigated for RF and anticitrulline antibodies.

Among men, exposure to any mineral oil was associated with a 30% increased relative risk of developing RA (relative risk = 1.3, 95% confidence interval = 1.0–1.7). When cases were subdivided into RF-positive RA and RF-negative RA, an increased risk was only observed for RF-positive RA (relative risk = 1.4, 95% confidence interval 1.0–2.0). When RA cases were subdivided according to the presence of anticitrulline antibodies, an increased risk associated with exposure to any mineral oil was observed only for anticitrulline-positive RA (relative risk = 1.6, 95% confidence interval = 1.1–2.2). Analysis of the interaction between oil exposure and the presence of HLA-DR shared epitope genes regarding the incidence of RA indicated that the increased risk associated with exposure to mineral oil was not related to the presence of shared epitope genotypes.

In conclusion, our study shows that exposure to mineral oil is associated with an increased risk to develop RF-positive RA and anticitrulline-positive RA, respectively. The findings are of particular interest since the same mineral oils can induce polyarthritis in rats.
PAX8-Peroxisome Proliferator-Activated Receptor γ (PPARγ) Disrupts Normal PAX8 or PPARγ Transcriptional Function and Stimulates Follicular Thyroid Cell Growth
Authors: Au Amy Y. M. , McBride Claire , Wilhelm Kenneth G. , Koenig Ronald J. , Speller Bridget , Cheung Linda , Messina Marinella , Wentworth John , Tasevski Vitomir , Learoyd Diana , Robinson Bruce G. , Clifton-Bligh Roderick J.
Published: September 2005

Follicular thyroid carcinomas are associated with a chromosomal translocation that fuses the thyroid-specific transcription factor paired box gene 8 (PAX8) with the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ). This study investigated the transcriptional mechanisms by which PAX8-PPARγ regulates follicular thyroid cells. In HeLa cells, rat follicular thyroid (FRTL-5) cells, or immortalized human thyroid cells, PAX8-PPARγ stimulated transcription from PAX8-responsive thyroperoxidase and sodium-iodide symporter promoters in a manner at least comparable with wild-type PAX8. In contrast, PAX8-PPARγ failed to stimulate transcription from the thyroglobulin promoter and blocked the synergistic stimulation of this promoter by wild-type PAX8 and thyroid transcription factor-1. Unexpectedly, PAX8-PPARγ transcriptional function on a PPARγ-responsive promoter was cell-type dependent; in HeLa cells, PAX8-PPARγ dominantly inhibited expression of the PPARγ-responsive promoter, whereas in FRTL-5 and immortalized human thyroid cells PAX8-PPARγ stimulated this promoter. In gel shift analyses, PAX8-PPARγ bound a PPARγ-response element suggesting that its transcriptional function is mediated via direct DNA contact. A biological model of PAX8-PPARγ function in follicular thyroid cells was generated via constitutive expression of the fusion protein in FRTL-5 cells. In this model, PAX8-PPARγ expression was associated with enhanced growth as assessed by soft agar assays and thymidine uptake. Therefore, PAX8-PPARγ disrupts normal transcriptional regulation by stimulating some genes and inhibiting others, the net effect of which may mediate follicular thyroid cell growth and loss of differentiation that ultimately leads to carcinogenesis.
The Aldosterone Synthase (CYP11B2) and 11β-Hydroxylase (CYP11B1) Genes Are Not Expressed in the Rat Heart
Authors: Ye P. , Kenyon C. J. , MacKenzie S. M. , Jong A. S. , Miller C. , Gray G. A. , Wallace A. , Ryding A. S. , Mullins J. J. , McBride M. W. , Graham D. , Fraser R. , Connell J. M. C. , Davies E.
Published: September 2005

Aldosterone synthase (CYP11B2) and 11β-hydroxylase (CYP11B1) catalyze the production of aldosterone and corticosterone, respectively, in the rat adrenal cortex. Recently, there has been some debate as to whether these corticosteroids are also produced in the hearts of rodents and humans, possibly contributing to the development of hypertrophy and myocardial fibrosis. To investigate this, we have used our established, highly sensitive real-time quantitative RT-PCR method to measure CYP11B1 and CYP11B2 mRNA levels in adrenal and cardiac tissue from several rat models of cardiovascular pathology. We have also studied isolated adult rat ventricular myocytes treated with angiotensin II and ACTH. Total RNA was isolated from the adrenal and cardiac tissue of 1) male Wistar rats with heart failure induced by coronary artery ligation and sham-operated controls; 2) stroke-prone spontaneously hypertensive rats and Wistar Kyoto rats as controls; 3) cyp1a1Ren-2 transgenic rats and Fischer controls; 4) isolated adult Sprague-Dawley ventricular myocytes incubated with 11-deoxycorticosterone (DOC), DOC plus angiotensin II, or DOC plus ACTH. Adrenal CYP11B2 expression was significantly increased in transgenic rats compared with Fischer controls (1.3 × 109± 1.2 × 109vs. 2.1 × 107± 7.0 × 106 copies/μg RNA; P < 0.05). There were no other significant differences in adrenal CYP11B2 or CYP11B1 expression between the model animals and their respective controls. Cardiac CYP11B1 and CYP11B2 mRNA transcript levels from all in vivo and in vitro groups were never greater than 100 copies per microgram total RNA and therefore too low to be detected reproducibly. This suggests that cardiac corticosteroid production is unlikely to be of any physiological or pathological significance.