bluuebunny/crossref_metadata_2025 huggingface dataset:
Powering Traffic Signals in an Emergency With Alternative Power Sources
Authors: Young William , Dovel John
Published: January 2009

Disasters, whether man-made or natural, destroy buildings, structures, lives and natural surroundings. As an example, Hurricane Andrew devastated South Florida with winds up to 140 miles per hour leaving more than 250,000 people homeless and severely damaging at least 85,000 buildings, in addition to traffic signals and other roadway devices. Traveling was hazardous with debris in the roadway, power lines down, traffic signals damaged or not working, and road signs missing. With so many traffic signals not working, normal traffic flow was disrupted and roadways became congested. The importance of maintaining traffic flow in a disaster was evident for effective movement of emergency vehicles and to support recovery efforts. The same effect is realized, but to a smaller degree, during brown-outs, severe storms, accidents and other power outages for whatever the cause. During power outages caused by disasters or other events, there are many traffic signals that are still functional, but not operational due to loss of electrical power. Recent advances in power electronics, lighting and alternative energy sources provide a means of making these functional traffic signals operational during power outages. Updating signal heads with new light emitting diode (LED) lamps will lower the energy consumption by 60 to 80 percent of that of existing incandescent lights. With lower power requirements, renewable energy sources such as photovoltaics, become capable of providing the needed electric power. Redesigning traffic signals to incorporate new low-energy technologies make renewables a more viable source of power. This paper addresses these issues with respect to energy consumption and describes a new design that uses renewables to power these new lighting technologies.
Pressure Drop in Solar Power Plant Chimneys
Authors: von Backstro¨m Theodore W. , Bernhardt Andreas , Gannon Anthony J.
Published: January 2009

The paper investigates the flow through a representative tall solar chimney with seven sets of internal bracing wheels with radial spokes. The paper presents experimental data measured in a 0.63 m diameter laboratory scale chimney model with and without bracing wheels. A fan at one end of the chimney model either sucked or blew the flow through it. The measured friction pressure drop was higher than theoretical values for smooth walls, and swirling, blown flow increased it by another 12%. The seven bracing wheels, each had twelve spokes, each spoke consisting of a pair of rectangular section bars, caused order of magnitude larger pressure drops than wall friction. For the sucked-through flow the forced, swirling, disturbed flow increased the pressure drop by up to 36%. Bracing wheels also increased the exit kinetic energy coefficient to 1.26 with the last wheel at the chimney exit. This effect could in combination with the bracing wheel drag reduce flow through the chimney. Designers of large chimneys should take care to minimise the number of bracing wheels, and possibly to streamline spoke sections. If possible, the top bracing wheel should be far enough from the exit for the flow to reattach to the wall after passing over the spoke attachment rim at the wall.
Study of Nanoindentation Using FEM Atomic Model
Authors: Jeng Yeau-Ren , Tan Chung-Ming
Published: January 2009

This paper adopts an atomic-scale model based on the nonlinear finite element formulation to analyze the stress and strain induced in a very thin film during the nanoindentation process. The deformation evolution during the nanoindentation process is evaluated using the quasi-static method, thereby greatly reducing the required computation time. The finite element simulation results indicate that the microscopic plastic deformation in the thin film is caused by instability of its crystalline structure, and that the magnitude of the nanohardness varies with the maximum indentation depth and the geometry of the indenter.
Simulation of Wear Through Mass Balance in a Dry Contact
Authors: Fillot Nicolas , Iordanoff Ivan , Berthier Yves
Published: January 2009

Numerical investigations are carried out to simulate wear and the analysis of these simulations leads to proposing an original new wear law that takes into account interfacial particles in the contact. A 3D Discrete Element Model is presented that simulates the detachment of particles, their flow in the contact and their ejection. It shows that a layer of detached particles can be formed at the interface, separating the solids in contact. The simulations show how influential the contact geometry and the properties of the interfacial particles are in studying wear. The processes of material degradation and particle ejection are then studied separately. Their physical behaviour is analysed and simple analytical expressions are proposed. Consideration of the mass balance of the contact provides an analytical law for wear, involving the fate of the detached particles. Classical wear laws (such as Archard’s law), assuming that no particle stays in the contact, appear to be a limit case of this model.
Friction Control of Active-Head Slider During Flying Height Adjustment
Authors: Su Lizhi , Xu Junguo , Kurita Masayuki , Kato Koji , Adachi Koshi , Miyake Yoshihiko
Published: January 2009

To reduce the risk of head crash when a slider contacts a smooth disk during flying height adjustment, a novel tapping method for reducing the friction and lowering the risk of head crash was developed. An active-head slider was designed and fabricated to demonstrate the usefulness of tapping approach. It is also found that micro-vibration is significantly effective in avoiding a high friction force and protecting a head from the crash due to head-disk contact during the flying height adjustment.
Analytical Instability Model for the Separation of a Sphere From a Flat in the Presence of a Liquid Film
Authors: Streator J. L.
Published: January 2009

An instability model is proposed to describe the process of separating a sphere from a flat in the presence of a lubricant. The model is based on consideration of the effects of sphere inertia in characterizing the critical point of separation — namely, that there is a sudden onset of significant sphere acceleration. Good agreement is found between the predictions of the instability model with those of a full numerical simulation. The instability model provides an improvement over an “impulse” model found in the literature, which is unable to predict the point of separation.
RF-MEMS Varactor With Minimal Contact
Authors: Shen Qin , Chasiotis Ioannis , Barker N. Scott
Published: January 2009

An innovative RF-MEMS varactor has been developed for use in distributed RF-MEMS circuits such as phase shifters and tunable matching networks where the capacitance ratio between on- and off- state must be limited to 2–10. By fabricating standoffs on the bottom side of the beam, this device eliminates the intimate contact between the FR-MEMS and dielectric, that is found in typical RF-MEMS beam capacitive switches. These standoffs limit the range of motion, allowing the capacitance ratio to be set, and also greatly reduces the contact area thus preventing stiction from occurring. The RF-MEMS switch has been fabricated with initial measurements demonstrating a capacitance ratio of 2.5. Preliminary reliability testing results demonstrate that this RF-MEMS design is very robust.
Adhesion Effects on Contact Opening Time in MEMS Switches
Authors: Jensen Brian D. , Chow Linda L.-W. , Kurabayashi Katsuo , Volakis John L.
Published: January 2009

Previous models and measurements of MEMs adhesion have focused on steady-state adhesion behavior. This approach is inadequate for micromachined switches (such as RF MEMS switches) because it gives no information about the time required for contact opening, an important specification. We propose a technique to measure the switch opening time and present substantial experimental data for switches with gold-gold contacts. The data demonstrate that contact opening time increases dramatically as contact dimple area increases or as pull-apart force or contact resistance decrease. A model of opening time is also presented with model parameters that fit the experimental data.
Non-Uniqueness, Eigenvalue Solutions and Wedged Configurations Involving Coulomb Friction
Authors: Barber J. R. , Hild P.
Published: January 2009

It is well known that the conventional Coulomb friction condition can lead to non-uniqueness of solution in elastostatic solutions if the friction coefficient is sufficiently high. Interest in this field has centered on discrete formulations, particularly with reference to the finite element method. More recently Hild has demonstrated the existence of a multiplicity of non-unique solutions to a simple problem in two-dimensional continuum elasticity and showed how to determine the conditions for such states to exist by formulating an eigenvalue problem. Both the discrete and continuum examples of non-uniqueness seem to be related to the well known physical phenomenon whereby a frictional system can become locked or ‘wedged’ in a state of stress even when no external loads are applied (the homogeneous problem), but the equivalence is not complete because of the influence of unilateral inequalities in the physical problem. We shall discuss the relations between these concepts in the context of simple continuum and discrete problems in two-dimensional linear elasticity.
Multiscale Roughness of MEMS Surfaces
Authors: Bora Can K. , Plesha Michael E. , Flater Erin E. , Street Mark D. , Carpick Robert W. , Redmond James M.
Published: January 2009

Investigation of contact and friction at multiple length scales is necessary for the design of surfaces in sliding microelectromechanical system (MEMS). A method is developed to investigate the geometry of asperities at different length scales. Analysis of density, height, and curvature of asperities on atomic force microscopy (AFM) images of actual silicon MEMS surfaces show these properties have a power law relationship with the sampling size used to define an asperity. This behavior and its similarity to results for fractal Weierstrass-Mandelbrot (W-M) function approximations indicate that a multiscale model is required to properly describe the surfaces.
Bouncing Mode Electrostatically Actuated Scanning Micromirror for Laser Display Applications
Authors: Krylov Viacheslav , Barnea Daniel I.
Published: January 2009

In laser display applications, the necessity to create images free of distortions imposes specific requirements on the motion of scanning devices. We present an approach of a scanning micromirror operation that is aimed to fulfill the requirements of motion linearity, high operational frequency and low actuation voltages. The operational mode incorporates a contact event between the mirror and an elastic constraint followed by a bouncing event and a subsequent inversion of motion. A stable limit cycle with voltage-dependent frequency and triangular response signal is obtained by the application of an actuation voltage which is piecewise constant in time. Approximate expressions relating the frequency and amplitude of the response with the actuating voltage are obtained by energy balance method. The influence of contact losses on the response as well as the stability of the limit cycle are studied numerically.
The Effect of Contact Morphology on Initiation and Propagation of Micro-Slip at Contact Interface
Authors: Adachi Koshi , Kato Koji , Liu Jun , Kawamura Hiroshi
Published: January 2009

In order to understand the mechanisms of micro-slip initiation and propagation at the contact interface, a visualization method of partial micro-slip at the contact interface was developed. The process of micro-slip initiation and propagation at the contact interface was successfully observed, and the relationship between tangential coefficient and partial slip distribution at the contact interface was analyzed by using the newly developed method. It was clarified that the partial slip distribution was affected by contact morphologies such as spherical ball, triangular stamp, rectangular stamp and concave stamp contact. The effect of uneven area of the contact surface on the micro-slip initiation and propagation was also clarified. It is confirmed from observed results that the visualization of the partial slip at the contact interface is useful for understanding the mechanism of the micro-slip initiation and the propagation at the contact interface.
Oral and Parenteral Therapeutic Options for Outpatient Urinary Infections Caused byEnterobacteriaceaeProducing CTX-M Extended-Spectrum β-Lactamases
Authors: Prakash Vidhya , Lewis James S. , Herrera Monica L. , Wickes Brian L. , Jorgensen James H.
Published: January 2009

Effective therapeutic options are needed for community-onset urinary tract infections due toEscherichia colistrains that produce CTX-M extended-spectrum β-lactamases. We examined 46 urinary isolates producing CTX-M against several oral or long-acting parenteral antimicrobial agents. Approximately 90% were susceptible to fosfomycin and to a combination of cefdinir plus amoxicillin-clavulanate. All were susceptible to ertapenem.
Simple Adhesive-Tape-Based Sampling of Tomato Surfaces Combined with Rapid Fluorescence In Situ Hybridization for
Salmonella
Detection
Authors: Bisha Bledar , Brehm-Stecher Byron F.
Published: January 2009

A simple adhesive-tape-based method for sampling of tomato surfaces was combined with fluorescence in situ hybridization for rapid culture-independent detection of
Salmonella
strains. Tapes could also be placed face-down on selective agar for on-tape enrichment of captured
Salmonella
cells. Overlay of cell-charged tapes with small volumes of liquid enrichment media enabled subsequent detection of tape-captured
Salmonella
via flow cytometry.
Simultaneous Interferometric Measurement of Corrosive or Demineralizing Bacteria and Their Mineral Interfaces
Authors: Waters M. S. , El-Naggar M. Y. , Hsu L. , Sturm C. A. , Luttge A. , Udwadia F. E. , Cvitkovitch D. G. , Goodman S. D. , Nealson K. H.
Published: January 2009

Here, we report simultaneous surface profile measurements of several bacterial species involved in microbially influenced corrosion and their solid-surface interfaces by using vertical scanning interferometry. The capacity to nondestructively quantify microscale topographic changes beneath a single bacterium without its removal offers a unique opportunity to examine in vivo microbe-surface interactions.
Diversity and Habitat Specificity of Free-Living Protozoa in Commercial Poultry Houses
Authors: Baré Julie , Sabbe Koen , Van Wichelen Jeroen , van Gremberghe Ineke , D'hondt Sofie , Houf Kurt
Published: January 2009

Despite stringent biosecurity measures, infections by bacterial food pathogens such as
Campylobacter
are a recurrent problem in industrial poultry houses. As the main transmission route remains unclear, persistence of these infections has been linked to bacterial survival and possibly multiplication within protozoan vectors. To date, however, virtually no information is available on the diversity and occurrence of free-living protozoa in these environments. Using a combination of microscopic analyses of enrichment cultures and molecular methods (denaturing gradient gel electrophoresis [DGGE]) on natural samples, we show that, despite strict hygiene management, free-living protozoa are common and widespread throughout a 6-week rearing period in both water and dry samples from commercial poultry houses. Protozoan communities were highly diverse (over 90 morphotaxa and 22 unique phylotypes from sequenced bands) and included several facultative pathogens and known bacterial vectors. Water samples were consistently more diverse than dry ones and harbored different communities, mainly dominated by flagellates. The morphology-based and molecular methods yielded markedly different results: amoebic and, to a lesser degree, ciliate diversity was seriously underestimated in the DGGE analyses, while some flagellate groups were not found in the microscopic analyses. Some recommendations for improving biosecurity measures in commercial poultry houses are suggested.
Potential effects of climate change on marine growth and survival of Fraser River sockeye salmon
Authors: Hinch Scott G. , Healey Michael C. , Diewert Ron E. , Henderson Michael A. , Thomson Keith A. , Hourston Roy , Juanes Francis
Published: January 2009

Simulation results from the Canadian Climate Centre's atmospheric general circulation model (CCC GCM) coupled to a simplified mixed-layer ocean model predict that doubled atmospheric CO2 concentrations would increase northeast Pacific Ocean sea surface temperatures and weaken existing north–south air pressure gradients. On the basis of predicted changes to air pressure and an empirical relationship between wind-driven upwelling and zooplankton biomass, we calculate that production of food for sockeye salmon (Oncorhynchus nerka) may decrease by 5–9%. We developed empirical relationships between sea surface temperature, zooplankton biomass, adult recruitment, and terminal ocean weight for the early Stuart stock of Fraser River sockeye salmon. Our analyses show that warmer sea surface temperatures, larger adult recruitment, and lower zooplankton biomass are correlated with smaller adult sockeye. Bioenergetics modeling suggests that higher metabolic costs in warmer water coupled with lower food availability could cause the observed reductions in size. Warmer sea surface temperatures during coastal migration by juveniles were correlated with lower recruitment 2 yr later. Warmer sea surface temperatures may be a surrogate for increased levels of predation or decreased food during the juvenile stage. We speculate that Fraser sockeye will be less abundant and smaller if the climate changes as suggested by the Canadian Climate Centre's general circulation model.
Lethal and sublethal effects of sponge overgrowth on introduced dreissenid mussels in the Great Lakes – St. Lawrence River system
Authors: Ricciardi Anthony , Snyder Fred L. , Kelch David O. , Reiswig Henry M.
Published: January 2009

Freshwater sponges in the Great Lakes – St. Lawrence River system overgrow and kill introduced zebra (Dreissena polymorpha) and quagga mussels (Dreissena bugensis) on solid substrates. Sponges overgrow and smother mussel siphons, thereby interfering with normal feeding and respiration. We tested the significance of sponge-enhanced mussel mortality by repeated sampling at several sites where both organisms were abundant in the upper St. Lawrence River and on an artificial reef in central Lake Erie. A small proportion (<10%) of the dreissenid population at each site was overgrown by sponge. Mussel colonies that were completely overgrown for 1 or more months invariably contained a significantly greater proportion of dead mussels than local uncovered populations. Mussels that survived prolonged periods (4–6 months) of overgrowth suffered significant tissue weight losses. Laboratory experiments and field observations suggest that dreissenids are not able to colonize sponges; therefore, sponges should always dominate competitive overgrowth situations. The overall impact of sponges on dreissenid populations in the Great Lakes – St. Lawrence River system will probably be negligible because of the high rate of mussel recruitment and the environmental constraints on sponge growth; however, our results suggest that sponges may control mussel abundance locally.
SCHEDULING AND MANAGEMENT OF VIRTUAL RESOURCES IN GRID SITES: THE SITE RESOURCE SCHEDULER
Authors: CALHEIROS RODRIGO N. , FERRETO TIAGO , DE ROSE CÉSAR A. F.
Published: January 2009

This paper presents a new approach to resource management and scheduling in computational grids, in order to simplify the vision users have from grid resources and their management. Scheduling decisions are moved to the site where resources are hosted, allowing quick response to changes in load and resource availability. Users do not need to be aware of the resources they use and are instead supplied with "virtual resources" representing the amount of computational power available to them in the site. This approach results in new challenges, like the management of two-level scheduling schema and the need to define a site capacity measure, but simplifies and optimizes scheduling in grids. In this paper we present details of this approach – called Site Resource Scheduler (SRS) – as well as some issues regarding its simulated performance and its deployment in a site. We show that the main advantage of this approach is an overall reduction in the execution time of tasks in most scenarios.
HASH-BASED OVERLAY PARTITIONING IN UNSTRUCTURED PEER-TO-PEER SYSTEMS
Authors: PAPADAKIS HARRIS , FRAGOPOULOU PARASKEVI , MARKATOS EVANGELOS P. , DIKAIAKOS MARIOS D. , LABRINIDIS ALEXANDROS
Published: January 2009

Unstructured peer-to-peer (P2P) networks suffer from the increased volume of traffic produced by flooding. Methods such as random walks or dynamic querying managed to limit the traffic at the cost of reduced network coverage. In this paper, we propose a partitioning method of the unstructured overlay network into a relative small number of distinct subnetworks. The partitioning is driven by the categorization of keywords based on a uniform hash function. The method proposed in this paper is easy to implement and results in significant benefit for the blind flood method. Each search is restricted to a certain partition of the initial overlay network and as a result it is much more targeted. Last but not least, the search accuracy is not sacrificed to the least since all related content is searched. The benefit of the proposed method is demonstrated with extensive simulation results, which show that the overhead for the implementation and maintenance of this system is minimal compared to the resulted benefit in traffic reduction.
RELATIONSHIPS BETWEEN REGULAR AND IRREGULAR COLLECTIVE COMMUNICATION OPERATIONS ON CLUSTERED MULTIPROCESSORS
Authors: Träff Jesper Larsson
Published: January 2009

We characterize collective communication operations on (clustered) multiprocessor systems in terms of their communication volume, and arrive at useful relationships between regular and irregular operations over sets of processors and sets of cluster-nodes, respectively. We show that regular problems over sets of processors induce corresponding irregular problems over sets of nodes. We hereby identify a symmetric variant of the personalized all-to-all communication problem that might be worth studying in its own right, and discuss an algorithm for solving this problem. From a simple algorithm for the regular all-gather problem over sets of processors, we derive an algorithm for the irregular all-gather problem over both sets of processors and sets of nodes. For communication libraries like MPI, the relationships emphasize the need for efficient algorithms for the irregular collective communication operations.
DEVELOPING PROXIMITY GRAPHS BY PHYSARUM POLYCEPHALUM: DOES THE PLASMODIUM FOLLOW THE TOUSSAINT HIERARCHY?
Authors: ADAMATZKY ANDREW
Published: January 2009

Plasmodium of Physarum polycephalum spans sources of nutrients and constructs varieties of protoplasmic networks during its foraging behavior. When the plasmodium is placed on a substrate populated with sources of nutrients, it spans the sources with protoplasmic network. The plasmodium optimizes the network to deliver efficiently the nutrients to all parts of its body. How exactly does the protoplasmic network unfold during the plasmodium's foraging behavior? What types of proximity graphs are approximated by the network? Does the plasmodium construct a minimal spanning tree first and then add additional protoplasmic veins to increase reliability and through-capacity of the network? We analyze a possibility that the plasmodium constructs a series of proximity graphs: nearest-neighbour graph (NNG), minimum spanning tree (MST), relative neighborhood graph (RNG), Gabriel graph (GG) and Delaunay triangulation (DT). The graphs can be arranged in the inclusion hierarchy (Toussaint hierarchy): NNG ⊆ MST ⊆ RNG ⊆ GG ⊆ DT . We aim to verify if graphs, where nodes are sources of nutrients and edges are protoplasmic tubes, appear in the development of the plasmodium in the order NNG → MST → RNG → GG → DT , corresponding to inclusion of the proximity graphs.
SELFISH ROUTING IN THE PRESENCE OF NETWORK UNCERTAINTY
Authors: GEORGIOU CHRYSSIS , PAVLIDES THEOPHANIS , PHILIPPOU ANNA
Published: January 2009

We study the problem of selfish routing in the presence of incomplete network information. Our model consists of a number of users who wish to route their traffic on a network of m parallel links with the objective of minimizing their latency. However, in doing so, they face the challenge of lack of precise information on the capacity of the network links. This uncertainty is modeled via a set of probability distributions over all the possibilities, one for each user. The resulting model is an amalgamation of the KP-model of [14] and the congestion games with user-specific functions of [22]. We embark on a study of Nash equilibria and the price of anarchy in this new model. In particular, we propose polynomial-time algorithms (w.r.t. our model's parameters) for computing some special cases of pure Nash equilibria and we show that negative results of [22], for the non-existence of pure Nash equilibria in the case of three users, do not apply to our model. Consequently, we propose an interesting open problem, that of the existence of pure Nash equilibria in the general case of our model. Furthermore, we consider appropriate notions for the social cost and the price of anarchy and obtain upper bounds for the latter. With respect to fully mixed Nash equilibria, we show that when they exist, they are unique. Finally, we prove that the fully mixed Nash equilibrium is the worst equilibrium.
ON A THEOREM OF DEDEKIND
Authors: KHANDUJA SUDESH K. , KUMAR MUNISH
Published: January 2009

Let K = ℚ(θ) be an algebraic number field with θ in the ring AK of algebraic integers of K and f(x) be the minimal polynomial of θ over the field ℚ of rational numbers. For a rational prime p, let [Formula: see text] be the factorization of the polynomial [Formula: see text] obtained by replacing each coefficient of f(x) modulo p into product of powers of distinct monic irreducible polynomials over ℤ/pℤ. Dedekind proved that if p does not divide [AK : ℤ[θ]], then the factorization of pAK as a product of powers of distinct prime ideals is given by [Formula: see text], with 𝔭i = pAK + gi(θ)AK, and residual degree [Formula: see text]. In this paper, we prove that if the factorization of a rational prime p in AK satisfies the above-mentioned three properties, then p does not divide [AK:ℤ[θ]]. Indeed the analogue of the converse is proved for general Dedekind domains. The method of proof leads to a generalization of one more result of Dedekind which characterizes all rational primes p dividing the index of K.
ACTION OF HECKE OPERATORS ON SIEGEL THETA SERIES, II
Authors: WALLING LYNNE H.
Published: January 2009

We apply the Hecke operators T(p)2 and [Formula: see text](1 ≤ j ≤ n ≤ 2k) to a degree n theta series attached to a rank 2k ℤ-lattice L equipped with a positive definite quadratic form in the case that L/pL is regular. We explicitly realize the image of the theta series under these Hecke operators as a sum of theta series attached to certain sublattices of [Formula: see text], thereby generalizing the Eichler Commutation Relation. We then show that the average theta series (averaging over isometry classes in a given genus) is an eigenform for these operators. We explicitly compute the eigenvalues on the average theta series, extending previous work where we had the restrictions that χ(p) = 1 and n ≤ k. We also show that [Formula: see text] for j > k when χ(p) = 1, and for j ≥ k when χ(p) = -1, and that θ( gen L) is an eigenform for T(p)2.
Role of Bile Acids and Bile Acid Receptors in Metabolic Regulation
Authors: Lefebvre Philippe , Cariou Bertrand , Lien Fleur , Kuipers Folkert , Staels Bart
Published: January 2009

The incidence of the metabolic syndrome has taken epidemic proportions in the past decades, contributing to an increased risk of cardiovascular disease and diabetes. The metabolic syndrome can be defined as a cluster of cardiovascular disease risk factors including visceral obesity, insulin resistance, dyslipidemia, increased blood pressure, and hypercoagulability. The farnesoid X receptor (FXR) belongs to the superfamily of ligand-activated nuclear receptor transcription factors. FXR is activated by bile acids, and FXR-deficient ( FXR−/−) mice display elevated serum levels of triglycerides and high-density lipoprotein cholesterol, demonstrating a critical role of FXR in lipid metabolism. In an opposite manner, activation of FXR by bile acids (BAs) or nonsteroidal synthetic FXR agonists lowers plasma triglycerides by a mechanism that may involve the repression of hepatic SREBP-1c expression and/or the modulation of glucose-induced lipogenic genes. A cross-talk between BA and glucose metabolism was recently identified, implicating both FXR-dependent and FXR-independent pathways. The first indication for a potential role of FXR in diabetes came from the observation that hepatic FXR expression is reduced in animal models of diabetes. While FXR−/−mice display both impaired glucose tolerance and decreased insulin sensitivity, activation of FXR improves hyperglycemia and dyslipidemia in vivo in diabetic mice. Finally, a recent report also indicates that BA may regulate energy expenditure in a FXR-independent manner in mice, via activation of the G protein-coupled receptor TGR5. Taken together, these findings suggest that modulation of FXR activity and BA metabolism may open new attractive pharmacological approaches for the treatment of the metabolic syndrome and type 2 diabetes.
Synthesis and Photoluminescence of Amorphous Ca5Ge2O9 Nanowires
Authors: Tsai Meng-Yen , Yu Chung-Yi , Perng Tsong-Pyng
Published: January 2009

A new method to prepare amorphous Ca5Ge2O9 nanowires is demonstrated in the present study. Germanium nanoparticles with the size ranging from 10 to 50 nm were first prepared by a vapor condensation technique. Upon immersing the nanoparticles in Ca(OH)2
aqueous solution, hydrated Ca5Ge2O9 nanowires were formed rapidly. The phase was determined by X-ray diffraction, and the stoichiometry of Ca:Ge was further confirmed by energy-dispersive X-ray spectroscopic and inductively coupled plasma-mass spectrometric
analyses. The diameter of nanowires varied from several tens to more than 100 nm, and the length increased with aging time up to the completion of reaction. After dehydrating at 400 °C, the nanowires became amorphous, and the stoichiometry of Ca:Ge remained unchanged. A blue-violet luminescence
was detected from these amorphous nanowires. The emission band distributed from 300 to 550 nm, with the main peak locating at 380 nm. Ge-associated luminescence centers are proposed to be responsible for this emission. The formation of amorphous Ca5Ge2O9 nanowires
may provide a new thinking to prepare other kinds of amorphous one-dimensional nanomaterials.
Detuning CD8+ T lymphocytes by down-regulation of the activating receptor NKG2D: role of NKG2D ligands released by activated T cells
Authors: Cerboni Cristina , Ardolino Michele , Santoni Angela , Zingoni Alessandra
Published: January 2009

NKG2D is an activating receptor expressed on CD8+αβ+ T cells, γδ+ T cells, natural killer (NK) cells, and some CD4+ T cells. For a long time, the interaction of NKG2D with its ligands (NKG2DLs) MICA, MICB, and ULBP1-3 has been considered a mechanism for recognition and elimination of tumor, infected, or otherwise “stressed” cells. However, a new role for NKG2D as an immunoregulatory receptor is emerging. Here, we show that NKG2D is strongly down-modulated on antigen-activated CD8+ T cells but only if CD4+ T cells are present. Down-modulation was caused by soluble factors produced by CD4+ T cells, and in particular soluble NKG2DLs were found in the supernatants of antigen-activated T-cell cultures. MICB was the ligand released at higher levels when CD4+ T cells were present in the cell cultures, suggesting that it could be the major player of NKG2D down-modulation. CD8+ T cells expressing low levels of NKG2D had impaired effector functions, as evaluated by proliferation, cytokine production, and cytotoxicity assays after combined triggering of NKG2D and TCR-CD3 complex. These findings show that activated CD4+ T cells expressing NKG2DLs can efficiently prevent NKG2D-mediated CD8+ T-cell functions, and suggest that the NKG2D/NKG2DL interaction can regulate immune responses.
Quantification of Fibronectin 1 (FN1) splice variants, including two novel ones, and analysis of integrins as candidate FN1 receptors in bovine preimplantation embryos
Authors: Goossens Karen , Van Soom Ann , Van Zeveren Alex , Favoreel Herman , Peelman Luc J
Published: January 2009

Background

Fibronectin 1 (FN1), a glycoprotein component of the extracellular matrix, exerts different functions during reproductive processes such as fertilisation, gastrulation and implantation. FN1 expression has been described to increase significantly from the morula towards the early blastocyst stage, suggesting that FN1 may also be involved in early blastocyst formation. By alternative splicing at 3 defined regions, different FN1 isoforms are generated, each with a unique biological function. The analysis of the alternative FN1 splicing on the one hand and the search for candidate FN1 receptors on the other hand during early bovine embryo development may reveal more about its function during bovine preimplantation embryo development.

Results

RT-qPCR quantification of the FN1 splice isoforms in oocytes, embryos, cumulus cells and adult tissue samples revealed a large variation in overall FN1 expression and in splice variant expression. Moreover, two new FN1 transcript variants were identified, the first one expressed in bovine preimplantation embryos and the second one expressed in cumulus cells.

In the search for candidate receptors for the new embryo specific FN1 isoform, RNA expression analysis identified 5 α integrin subunits (ITGA2B, ITGA3, ITGA5, ITGA8, ITGAV) and 2 β integrin subunits (ITGB1 and ITGB3) with a similar or overlapping RNA expression pattern as compared to FN1. But double immunofluorescent stainings could not confirm complete co-localisation between FN1 and one out of 3 selected integrins alpha subunits (ITGA3, ITGA5, ITGAV).

Conclusion

The existence of a new FN1 transcript variant, specifically expressed in morulae and blastocysts strengthens the idea that FN1 is involved in the process of compaction and blastocyst formation. Analysis of the integrin expression could not identify the binding partner for the embryo specific FN1 transcript variant making further steps necessary for the identification of the FN1 receptor and the downstream effects of FN1-receptor binding.
Regeneration of the radial nerve cord in the sea cucumber Holothuria glaberrima
Authors: San Miguel-Ruiz José E , Maldonado-Soto Angel R , García-Arrarás José E
Published: January 2009

Background

Regeneration of neurons and fibers in the mammalian spinal cord has not been plausible, even though extensive studies have been made to understand the restrictive factors involved. New experimental models and strategies are necessary to determine how new nerve cells are generated and how fibers regrow and connect with their targets in adult animals. Non-vertebrate deuterostomes might provide some answers to these questions. Echinoderms, with their amazing regenerative capacities could serve as model systems; however, very few studies have been done to study the regeneration of their nervous system.

Results

We have studied nerve cord regeneration in the echinoderm Holothuria glaberrima. These are sea cucumbers or holothurians members of the class Holothuroidea. One radial nerve cord, part of the echinoderm CNS, was completely transected using a scalpel blade. Animals were allowed to heal for up to four weeks (2, 6, 12, 20, and 28 days post-injury) before sacrificed. Tissues were sectioned in a cryostat and changes in the radial nerve cord were analyzed using classical dyes and immmuohistochemistry. In addition, the temporal and spatial distribution of cell proliferation and apoptosis was assayed using BrdU incorporation and the TUNEL assay, respectively.

We found that H. glaberrima can regenerate its radial nerve cord within a month following transection. The regenerated cord looks amazingly similar in overall morphology and cellular composition to the uninjured cord. The cellular events associated to radial cord regeneration include: (1) outgrowth of nerve fibers from the injured radial cord stumps, (2) intense cellular division in the cord stumps and in the regenerating radial nerve cords, (3) high levels of apoptosis in the RNC adjacent to the injury and within the regenerating cord and (4) an increase in the number of spherule-containing cells. These events are similar to those that occur in other body wall tissues during wound healing and during regeneration of the intestine.

Conclusion

Our data indicate that holothurians are capable of rapid and complete regeneration of the main component of their CNS. Regeneration involves both the outgrowth of nerve fibers and the formation of neurons. Moreover, the cellular events employed during regeneration are similar to those involved in other regenerative processes, namely wound healing and intestinal regeneration. Thus, holothurians should be viewed as an alternative model where many of the questions regarding nervous system regeneration in deuterostomes could be answered.
Gene expression profiling of whole blood: Comparison of target preparation methods for accurate and reproducible microarray analysis
Authors: Vartanian Kristina , Slottke Rachel , Johnstone Timothy , Casale Amanda , Planck Stephen R , Choi Dongseok , Smith Justine R , Rosenbaum James T , Harrington Christina A
Published: January 2009

Background

Peripheral blood is an accessible and informative source of transcriptomal information for many human disease and pharmacogenomic studies. While there can be significant advantages to analyzing RNA isolated from whole blood, particularly in clinical studies, the preparation of samples for microarray analysis is complicated by the need to minimize artifacts associated with highly abundant globin RNA transcripts. The impact of globin RNA transcripts on expression profiling data can potentially be reduced by using RNA preparation and labeling methods that remove or block globin RNA during the microarray assay. We compared four different methods for preparing microarray hybridization targets from human whole blood collected in PAXGene tubes. Three of the methods utilized the Affymetrix one-cycle cDNA synthesis/in vitro transcription protocol but varied treatment of input RNA as follows: i. no treatment; ii. treatment with GLOBINclear; or iii. treatment with globin PNA oligos. In the fourth method cDNA targets were prepared with the Ovation amplification and labeling system.

Results

We find that microarray targets generated with labeling methods that reduce globin mRNA levels or minimize the impact of globin transcripts during hybridization detect more transcripts in the microarray assay compared with the standard Affymetrix method. Comparison of microarray results with quantitative PCR analysis of a panel of genes from the NF-kappa B pathway shows good correlation of transcript measurements produced with all four target preparation methods, although method-specific differences in overall correlation were observed. The impact of freezing blood collected in PAXGene tubes on data reproducibility was also examined. Expression profiles show little or no difference when RNA is extracted from either fresh or frozen blood samples.

Conclusion

RNA preparation and labeling methods designed to reduce the impact of globin mRNA transcripts can significantly improve the sensitivity of the DNA microarray expression profiling assay for whole blood samples. While blockage of globin transcripts during first strand cDNA synthesis with globin PNAs resulted in the best overall performance in this study, we conclude that selection of a protocol for expression profiling studies in blood should depend on several factors, including implementation requirements of the method and study design. RNA isolated from either freshly collected or frozen blood samples stored in PAXGene tubes can be used without altering gene expression profiles.
HER-2/neu amplification testing in breast cancer by Multiplex Ligation-dependent Probe Amplification: influence of manual- and laser microdissection
Authors: Moelans Cathy B , de Weger Roel A , Ezendam Chantal , van Diest Paul J
Published: January 2009

Background

Accurate assessment of HER-2/neu status is crucial for proper prognostic information and to offer direct appropriate treatment for breast cancer patients. Next to immunohistochemistry (IHC) to evaluate HER2 protein overexpression, a second line gene amplification test is generally deemed necessary for cases with equivocal protein expression. Recently, a new PCR based test, called Multiplex Ligation-dependent Probe Amplification (MLPA), was introduced as a simple and quick method to assess HER-2/neu gene amplification status in invasive breast cancer. MLPA was previously shown to correlate well with IHC and in situ hybridization (ISH), but a low tumor percentage in the tissue tested could negatively affect the accuracy of MLPA results.

Methods

To examine this, MLPA was repeated in 42 patients after serial H&E section guided manual dissection with a scalpel and after laser microdissection of the tumor.

Results

Both dissection techniques led to higher HER2 gene copy number ratios and thereby made MLPA more quantitative. Concordance between MLPA and ISH improved from 61% to 84% after manual microdissection and to 90% after laser microdissection.

Conclusion

Manual and laser microdissection similarly increase the dynamic range of MLPA copy number ratios which is a technical advantage. As clinically a dichotomization between normal and amplified suffices and MLPA is relatively unsensitive to tumor content, microdissection before MLPA may not be routinely necessary but may be advisable in case of very low tumor content (≤30%), when MLPA results are equivocal, or when extensive ductal carcinoma in situ is present. Since differences between manual and laser microdissection were small, less time consuming manual microdissection appears to be sufficient.
Physical characteristics of the back are not predictive of low back pain in healthy workers: A prospective study
Authors: Van Nieuwenhuyse An , Crombez Geert , Burdorf Alex , Verbeke Geert , Masschelein Raphael , Moens Guido , Mairiaux Philippe ,   the BelCoBack Study Group
Published: January 2009

Background

In the working population, back disorders are an important reason for sick leave and permanent work inability. In the context of fitting the job to the worker, one of the primary tasks of the occupational health physician is to evaluate the balance between work-related and individual variables. Since this evaluation of work capacity often consists of a physical examination of the back, the objective of this study was to investigate whether a physical examination of the low back, which is routinely performed in occupational medicine, predicts the development of low back pain (LBP).

Methods

This study is part of the Belgian Low Back Cohort (BelCoBack) Study, a prospective study to identify risk factors for the development of low back disorders in occupational settings. The study population for this paper were 692 young healthcare or distribution workers (mean age of 26 years) with no or limited back antecedents in the year before inclusion. At baseline, these workers underwent a standardised physical examination of the low back. One year later, they completed a questionnaire on the occurrence of LBP and some of its characteristics. To study the respective role of predictors at baseline on the occurrence of LBP, we opted for Cox regression with a constant risk period. Analyses were performed separately for workers without any back antecedents in the year before inclusion ('asymptomatic' workers) and for workers with limited back antecedents in the year before inclusion ('mildly symptomatic' workers).

Results

In the group of 'asymptomatic' workers, obese workers showed a more than twofold-increased risk on the development of LBP as compared to non-obese colleagues (RR 2.57, 95%CI: 1.09 – 6.09). In the group of 'mildly symptomatic' workers, the self-reports of pain before the examination turned out to be most predictive (RR 3.89, 95%CI: 1.20 – 12.64).

Conclusion

This study showed that, in a population of young workers wh no or limited antecedents of LBP at baseline, physical examinations, as routinely assessed in occupational medicine, are not useful to predict workers at risk for the development of back disorders one year later.
Comparative study on the immunogenicity between an HLA-A24-restricted cytotoxic T-cell epitope derived from survivin and that from its splice variant survivin-2B in oral cancer patients
Authors: Kobayashi Jun-ichi , Torigoe Toshihiko , Hirohashi Yoshihiko , Idenoue Satomi , Miyazaki Akihiro , Yamaguchi Akira , Hiratsuka Hiroyoshi , Sato Noriyuki
Published: January 2009

Background

We previously reported an HLA-A24-restricted cytotoxic T-cell epitope, Survivin-2B80-88, derived from a splice variant of survivin, survivin-2B. In this report, we show a novel HLA-A24-restricted T-cell epitope, Survivin-C58, derived from a wild type survivin, and compared their immunogenicity in oral cancer patients.

Methods

By stimulating peripheral blood lymphocytes of HLA-A24-positive cancer patients with Survivin-C58 peptidein vitro, the peptide-specific CTLs were induced. In order to compare the immunogenic potential between C58 peptide and 2B80-88 peptide, peripheral blood T-cells from thirteen HLA-A24-positive oral cancer patients were stimulated with either or both of these two peptides.

Results

Survivin-2B80-88 peptide-specific CTLs were induced from four patients, and C58 peptide-specific CTLs were induced from three out of eight patients with over stage II progression. The CTLs exerted cytotoxicity against HLA-A24-positive tumor cells. In contrast, CTL induction failed from a healthy volunteer and all four patients with cancer stage I.

Conclusion

It was indicated that a splicing variant-derived peptide and wild type survivin-derived peptide might have a comparable potency of CTL induction, and survivin targeting immunotherapy using survivin-2B80-88 and C58 peptide cocktail should be suitable for HLA-A24+ oral cancer patients.
Extramammary Paget's disease of the penis: a case report and review of the literature
Authors: Ekwueme Kingsley C , Zakhour Hani D , Parr Nigel J
Published: January 2009

Introduction

Extramammary Paget's disease is a rare cutaneous, slow growing, intraepithelial adenocarcinoma developing in the apocrine gland-bearing areas. Isolated Paget's disease of the penis is extremely rare.

Case presentation

We describe the case of an 87-year-old Caucasian male who presented with a non-healing erythematous plaque on the shaft of the penis previously misdiagnosed as Bowen's disease. The diagnosis was made histologically on the excised specimen and was supported by immunohistochemical staining.

Conclusion

Extramammary Paget's disease is a rare disease which can mimic various types of dermatosis. A high index of suspicion is required, combined with biopsy and immunohistochemical staining in order to make the correct diagnosis. Long-term follow-up is mandatory in these patients in order to identify and treat any subsequent recurrence or concurrent malignancy.