bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulating the Marketing of Tobacco Products and Controlling Smoking in Canada
Authors: Wyckham Robert G.
Published: September 2010

The past two decades have seen an escalating struggle among the tobacco industry, the government, and anti‐smoking organizations in Canada. Increasingly, the marketing and the consumption of tobacco products have been constrained. After the passage of the Tobacco Products Control Act and the Non‐smokers' Health Act in 1988, Canada was said to have among the world's strongest tobacco promotion and smoking regulations. Now that key provisions of the Tobacco Products Control Act have been struck down by the Supreme Court of Canada and new legislation has been introduced in Parliament, it seems appropriate to examine the history of the regulation of tobacco products marketing and the control of smoking in this county. This paper provides a snapshot of tobacco sales since the 1960s and. outlines the chronology of past attempts to govern the marketing of cigarettes and to constrain smoking. Based on this experience it is recommended that a new organizational approach be examined. A quasi‐crown corporation staffed by experts in consumer package goods marketing is suggested as a way to counter the sophisticated tactics and strategies of the tobacco industry.

Au cours des deux dernières décennies, le Canada a été le théǎtre d'une vigoureuse escalade entre I'industrie du tabac, les pouvoirs publics et le lobby anti‐tabac. Le marketing et la consommation des produits du tabac ont été de plus en plus réprimés. Depuis I'adoption de la Loi réglementant les produits du tabac et de la Loi sur la santé des non‐fumeurs en 1988, le Canada passe parmi les pays à s'ětre dotés de I'une des réglementations les plus exigeantes du monde sur la promotion et I'usage du tabac. À présent que la Cour suprěme a rejeté les prin‐cipales clauses de la Loi réglementant les produits du tabac et que le Parlement est saisi d'une nouvelle législation sur la question, le moment est venu d'examiner I'histoire de la régulation du marketing des produits du tabac ainsi que la réglementation de I'usage du tabac au pays. L'article donne un aperçu des ventes du tabac depuis les années 60 et établit la chronologie des tenta‐tives destinées à régir le marketing des cigarettes et à juguler I'habitude defumer. Sur la base de cette expérience, Vauteur recommande d'envisager une nouvelle approche organisationnelle. II propose notamment de créer une société apparentée à une société de la Couronne (quasi‐crown corporation) dont feraient par‐tie des experts en marketing de Vemballage des produits de consommation pour contrer les tactiques et les stratégies évoluées de l'industrie du tabac.
Multi-Objective Optimal Design of Stationary Flat-Plate Solar Collectors Under Probabilistic Uncertainty
Authors: Rao Singiresu S. , Hu Yi
Published: September 2010

The multi-objective optimum design of stationary flat-plate solar collectors under probabilistic uncertainty is considered. The clear day solar beam radiation and diffuse radiation at the location of the solar collector are estimated. Three objectives are considered in the optimization problem formulation: maximization of the annual average incident solar energy, maximization of the lowest month incident solar energy, and minimization of the cost. The game theory methodology is used for the solution of the three objective constrained optimization problem. A parametric study is conducted with respect to changes in the standard deviation of the mean values of random variables and probability of constraint satisfaction. The present study is expected to help designers in creating optimized solar collectors based on specified requirements.
A Methodology for Identifying Environmentally Conscious Guidelines for Product Design
Authors: Telenko Cassandra , Seepersad Carolyn Conner
Published: September 2010

A reverse engineering methodology is presented for identifying environmentally conscious design guidelines for use in the conceptual stages of product design. Environmentally conscious principles and guidelines help designers improve environmental impacts of products by making better decisions during conceptual design stages when data for life cycle analysis (LCA) are sometimes scarce. The difficulty in using the current knowledge base of guidelines is that it is not exhaustive and conflicts are not well understood. In response, the authors propose a general method for expanding the current set of guidelines and for understanding potential environmental tradeoffs. The method helps designers extract environmentally conscious design guidelines from a set of functionally related products by combining reverse engineering with LCA. The guidelines and LCA results can then be used to inform subsequent design cycles without repeating the process. Although in environmentally conscious design, reverse engineering is commonly applied to studies of disassembly and recyclability, the methodology and case study herein show how reverse engineering can be applied to the utilization stage of a product’s life cycle as well. The method is applied to an example of electric kettles to demonstrate its utility for uncovering new design guidelines.
A Device for Harvesting Energy From Rotational Vibrations
Authors: Trimble A Zachary , Lang Jeffrey H. , Pabon Jahir , Slocum Alexander
Published: September 2010

A new device designed to harvest rotational vibration energy is presented. The device is modeled as a spring-mass-damper system connected to a vibration source where a torsion rod is used as a spring element and a shearing electromagnetic induction circuit as the energy harvesting element. The device is inherently a resonant type harvester. A prototype device is tested using a purely sinusoidal vibration input and more realistic inputs consisting of wider bandwidths, multiple resonance peaks, and low amplitude noise. The performance of the prototype to realistic inputs verifies the ongoing challenge to vibration energy harvesting, namely, significant loss of performance when using broadband inputs with resonant based devices.
An Alternative Hydrodynamic Force Model for Finite Bearings
Authors: Bastani Yaser , de Queiroz Marcio
Published: September 2010

A method for determining a closed-form expression for the hydrodynamic forces in finite plain journal bearings is introduced. The method is based on applying correction functions to the force models of the infinitely-long (IL) or infinitely-short (IS) bearing approximation. The correction functions are derived by modeling the ratio between the forces from the numerical integration of the two-dimensional Reynolds equation and the forces from either the IL or IS bearing approximation. Low-order polynomial models, dependent on the eccentricity ratio and aspect ratio, are used for the correction functions. The models are shown to outperform the standard limiting approximations in the steady-state analysis of the bearing system under static loading.
A Lyapunov Treatment of Swarm Coordination Under Conflict
Authors: McCullough Paul , Bacon Mark , Olgac Nejat , Sierra Daniel A.
Published: September 2010

This document considers hostile conflicts between two swarms, called pursuers and evaders, based on a double integrator model. In order to convert the marginally stable dynamics into stable-capture behavior, we introduce a control strategy based on the relative positions and velocities of opposing swarm members. To evaluate its effectiveness, a Lyapunov-based stability analysis is performed. For simplicity, this document considers swarms with equal membership strengths and equal mass only. The modeling is based on a set of suggested interaction force profiles, which are functions of local vectors. The group pursuit is conceived in two phases: the approach phase during which the two swarms act like two individuals; and the assigned pursuit phase where each pursuer is assigned to an evader.
Gain Scheduling-Inspired Control for Nonlinear Partial Differential Equations
Authors: Siranosian Antranik A. , Krstic Miroslav , Smyshlyaev Andrey , Bement Matt
Published: September 2010

We present a control design method for nonlinear partial differential equations (PDEs) based on a combination of gain scheduling and backstepping theory for linear PDEs. A benchmark first-order hyperbolic system with a destabilizing in-domain nonlinearity is considered first. For this system a nonlinear feedback law based on gain scheduling is derived explicitly, and a statement of stability is presented for the closed-loop system. Control designs are then presented for a string and shear beam PDE, both with Kelvin-Voigt damping and potentially destabilizing free-end nonlinearities. String and beam simulation results illustrate the merits of the gain scheduling approach over the linearization-based design.
Physical Modeling and Control of a Multi-Cylinder HCCI Engine
Authors: Ravi Nikhil , Roelle Matthew J. , Liao Hsien-Hsin , Jungkunz Adam F. , Chang Chen-Fang , Gerdes J. Christian
Published: September 2010

Homogeneous charge compression ignition (HCCI) is one of the most promising piston-engine concepts for the future, providing significantly improved efficiency and emissions characteristics relative to current technologies. This paper presents a framework for controlling a multi-cylinder HCCI engine with exhaust recompression and direct injection of fuel into the cylinder. A physical model is used to describe the HCCI process, with the model states being closely linked to the thermodynamic state of the cylinder constituents. Separability between the effects of the control inputs on the desired outputs provides an opportunity to develop a simple linear control scheme, where the fuel is used to control the work output and the valve timings are used to control the phasing of combustion. Experimental results show good tracking of both the work output and combustion phasing over a wide operating region. In addition, the controller is able to balance out differences between cylinders, and reduce the cycle-to-cycle variability of combustion.
Camera Based Measurement of Side Slip Angle in an Automobile
Authors: Harchut Frank , Mueller-Bessler Bernhard
Published: September 2010

For vehicle dynamics applications, automotive companies are interested in determining the precise vehicle state in every driving situation in real-time. Part of the vehicle state is the side slip angle—the angle between the vehicle heading and its direction of movement. Currently the side slip angle is not measured in stock cars. To fill the gap this paper presents a basic proof of concept to measure the side slip angle using stock car components for sensing. These include an automotive camera and additional movement information provided in current production passenger cars. A basic computer vision algorithm allows determination of camera movement through the identification of static objects in consecutive camera images. In conjunction with a kinematical model, this data is then used to derive the car’s side slip angle. Finally, the method is evaluated on a real vehicle, with dGPS providing ground truth.
Discrete Partitioning and Coverage Control With Gossip Communication
Authors: Durham Joseph W. , Carli Ruggero , Frasca Paolo , Bullo Francesco
Published: September 2010

In this paper we propose distributed algorithms to automatically deploy a group of robotic agents and provide coverage of a discretized environment represented by a graph. We present a discrete coverage algorithm which converges to a centroidal Voronoi partition while requiring only pairwise “gossip” communication between the agents. Our theoretical analysis is based on a dynamical system on partitions of the graph’s vertices. We also establish bounds on the computational requirements of the algorithm and demonstrate its functionality with simulations.
Control-Oriented Modeling of a Solid-Oxide Fuel Cell Stack Using an LPV Model Structure
Authors: Sanandaji Borhan M. , Vincent Tyrone L. , Colclasure Andrew , Kee Robert J.
Published: September 2010

For efficient operation, as well as to avoid operating conditions that can cause damage, fuel cells require a control system to balance fuel and air supply and electrical load. The need to maintain signal constraints during operation, combined with importance of unmeasured variables such as internal stack temperature or fuel utilization, indicate the need for control-oriented models that can be used for estimation and model predictive control. In this paper, we discuss the development of a control-oriented dynamic model of a solid oxide fuel cell stack. Using a detailed physical model as a starting point, we demonstrate the utility of a linear parameter varying (LPV) model structure as a mechanism for model reduction. A novel feature is a non-parametric method for determining the scheduling functions in this model.
Stochastic Estimation of Multi-Variable Human Ankle Mechanical Impedance
Authors: Rastgaar Mohammad A. , Ho Patrick , Lee Hyunglae , Krebs Hermano Igo , Hogan Neville
Published: September 2010

This article presents preliminary stochastic estimates of the multi-variable human ankle mechanical impedance. We employed Anklebot, a rehabilitation robot for the ankle, to provide torque perturbations. Time histories of the torques in Dorsi-Plantar flexion (DP) and Inversion-Eversion (IE) directions and the associated angles of the ankle were recorded. Linear time-invariant transfer functions between the measured torques and angles were estimated for the Anklebot and when the Anklebot was worn by a human subject. The difference between these impedance functions provided an estimate of the mechanical impedance of the ankle. High coherence was observed over a frequency range up to 30 Hz, indicating that this procedure yielded an accurate measure of ankle mechanical impedance in DP and IE directions.
Application of an Exhaust Geometry Based Delay Prediction Model to Internal Combustion Engines
Authors: Meyer Jason , Rajagopalan Sai S. V. , Midlam-Mohler Shawn , Yurkovich Stephen , Guezennec Yann
Published: September 2010

All vehicle manufacturers implement an air-to-fuel ratio (AFR) control system for emissions reduction in gasoline engines. When using a model based control structure, it is vital to capture the underlying dynamics of the plant as accurately as possible, thus facilitating a robust control design that meets the emissions regulation requirements. One of the leading sources of uncertainty in the engine model is the variable plant delay. Although the delay could be modeled using a look-up table of steady-state delay values, during transients when AFR control is most important the steady-state delay poorly approximates the true delay. An exhaust geometry based delay model was developed previously within the framework of a model based control design for AFR control of stoichiometric engines. In this paper, it is shown that using this model the delay can be predicted with a significantly higher accuracy especially during transients, thus improving emissions performance. Because the plant delay plays a destabilizing role in feedback control, the utility of such a model is also to minimize phase errors between the predicted and measured equivalence ratio (EQR) in a reference tracking control setting.
Parameter Varying Control of an Electrostatic MEMS Actuator
Authors: Shirazi Farzad A. , Mohammadpour Javad , Grigoriadis Karolos M.
Published: September 2010

The present paper employs a linear parameter-varying (LPV) control design approach with H∞ performance specification for set-point tracking of deflection in an electrostatic MEMS actuator. First, we model the system dynamics in an LPV framework, considering the actuation charge as the scheduling parameter. Then, we design an H∞ parameter-dependant state feedback controller, where its static gain is scheduled based on the LPV parameter. The states of the modeled LPV system are estimated using an LPV observer whose design is addressed in the paper. The simulation results presented in the paper provide asymptotic stability and desired performance against pull-in effect and vibration disturbance. Also the performance of the LPV controller is compared with a fixed H∞ controller to demonstrate that the LPV controller provides smaller settling time, lower overshoot and hence improved transient and steady-state performance over full range of device operation.
Direct Adaptive Disturbance Observer Design for Rejecting the Narrow-Band Disturbance With Unknown Frequency in Hard Disk Drives
Authors: Zheng Qixing , Tomizuka Masayoshi
Published: September 2010

This paper presents an adaptive add-on compensator to handle a single narrow-band disturbance with unknown frequency in hard disk drives (HDDs). A disturbance observer (DOB) loop with a narrow band pass Q filter is built around the baseline servo controller to reject the narrow-band disturbance. The frequency parameter of the Q filter is directly adapted to the optimal value in the sense of minimizing the track following track mis-registration (TMR). The performance of the proposed compensator is demonstrated by simulation on an open-source realistic hard disk drive system.
Classifier Design for Sensor-Fault Tolerant Condition Monitoring in an Industrial Machine
Authors: Raman Srinivas , de Silva Clarence W.
Published: September 2010

This paper presents a comparative evaluation of two classification schemes that can be used to accurately diagnose the health of machines in the presence of sensor failure. In the developed approach, multiple sensors acquire vibration and sound signals from a machine and the signals are represented using the Wavelet Packet Transform (WPT). A “wrapper” feature selection procedure is used to reduce the size of the feature set without sacrificing the classification accuracy. The performance of a Radial Basis Function Network (RBFN) is compared with that of a Support Vector Machine (SVM) by simulating and monitoring machine and sensor faults in an industrial fish cutting machine. Initial results show an 85% reduction in feature set size for an RBFN and a 92.5% reduction in feature set size for a SVM.
An Analysis of Micro Aeroelastic Energy Harvesting Devices
Authors: Cole Daniel G. , Weiland Lisa M.
Published: September 2010

New micro renewable energy harvesting devices are being developed using the stable limit cycle response of aeroelastic systems to drive energy conversion. This paper analyzes such devices. This paper investigates devices that use two types of aeroelastic instability: galloping and multi-mode flutter. Since the generation of power can be stabilizing, resulting in no power generation at all, the analysis begins by analyzing the stability of such devices from the perspective of power generation. Next, the level of power generation is discussed, and peak levels of performance are found. The analysis suggests that with proper tuning the power generation of micro aeroelastic energy harvesters operating at representative speeds (∼4.5 m/s (10 mph)) can produce power on the order of 10 mW.
Desired Compensation Adaptive Robust Contouring Control of an Industrial Biaxial Precision Gantry Subject to Cogging Forces
Authors: Hu Chuxiong , Yao Bin , Wang Qingfeng
Published: September 2010

To obtain a higher level of contouring motion control performance for linear-motor-driven multi-axes mechanical systems subject to significant nonlinear cogging forces, both coordinated control of multi-axes motions and effective compensation of cogging forces are necessary. In addition, the effect of unavoidable velocity measurement noises needs to be carefully examined and sufficiently attenuated. To solve these problems simultaneously, in this paper, a discontinuous projection based desired compensation adaptive robust contouring controller is developed by explicitly taking into account the specific characteristics of cogging forces in the controller designs and employing the task coordinate formulation for coordinated motion controls. Specifically, based on the largely periodic nature of cogging forces with respect to position, design models consisting of known sinusoidal functions of positions corresponding to the main harmonics of the force ripple waveforms with unknown weights are used to approximate the unknown cogging forces. Theoretically, the resulting controller achieves a guaranteed transient performance and final contouring accuracy in the presence of both parametric uncertainties and uncertain nonlinearities. In addition, the controller also achieves asymptotic output tracking when there are parametric uncertainties only. Comparative experimental results obtained on a high-speed industrial biaxial precision gantry driven by linear motors are presented to verify the excellent contouring performance of the proposed control scheme and the effectiveness of the cogging force compensations.
PWM Synchronization for Intelligent Agent Scarce Resource Auction
Authors: Burke William , Auslander David
Published: September 2010

This paper is focuses on modulating a shared resource, power demand on the electricity grid, among intelligent agents charged with modulating residential HVAC systems. We discuss the use of synchronized control actuation signals (PWM) to simplify scarce resource auctions for control of a network of intelligent home agents. By synchronizing the actuation signal with the auction times, identification and prediction becomes simpler, and modulation of the shared resource is as easy as adjusting the saturation limits of the controller. We show results through simulation.
Model-Based Fault Detection and Diagnosis for Electromagnetic Valve Drives
Authors: Beck Mark , Muenchhof Marco , Isermann Rolf
Published: September 2010

This paper describes the model-based fault detection and diagnosis for electromagnetic actuators. Due to hysteresis behavior, the model of Jiles and Atherton is used to capture these hysteretic effects. It is shown that the use of this model results in superior model fidelity and allows to detect even tiny, incipient faults at the actuator. The method has been applied to a direct-driven proportional valve of an electro-hydraulic servo axis and has been tested extensively on a real testbed.
Wind Shear Modeling for Wind Turbine Siting Studies
Authors: Turner Trevor B. , Schkoda Ryan F. , Wagner John R. , Leitner Robert T.
Published: September 2010

A wind turbine generator offers a green renewable alternative to the traditional fossil and nuclear fuel processes to generate electrical power. Both wind energy technology and wind turbine farm designs remain in demand given the current growth in energy requirements and the public’s preference for clean sources. Simply put, wind energy offers a safe, relatively cost effective solution for global energy production. For example, the energy demand for populated coastal cities encourages offshore farms to fulfill future electrical needs. Similarly, wind turbines may be placed in land-locked regions and power transmitted through electric grids to population centers. Most wind models available to engineers offer superb capabilities for predicting wind velocities on land and far offshore (5 km and greater). However, near shore winds have proven difficult to determine due to surface roughness, thermal stratification, and abrupt displacement height variances. This paper discusses the model comparison of two foremost wind speed prediction tools, AWS Truewinds’ MASS and WindPro’s WAsP. The model comparison is related to measured South Carolina coastal data and suggests AWS Truewind’s MASS wind shear model is the more effective near-shore wind speed prediction tool. In arriving at these results, several areas of future work are discussed.
Gravity Powered Locomotion and Active Control of Two Simple Systems
Authors: Tavakoli Ali , Hurmuzlu Yildirim
Published: September 2010

The goal of this research is to develop energetically efficient robots that can produce stable gait. One cannot ignore the promise of robots that can walk by using very little energy. Gravity powered bipeds provide ample proof that this is possible. It is conceivable that mechanisms that are much simpler than legged robots can also produce gravity powered locomotion. It is also plausible that one can get deeper understanding of the dynamics of such simple mechanisms. In addition, evolutionary biology tells us that one can learn a great deal by studying the hereditary traits of organisms that evolve over generations. Thus, we study a chain of mechanisms that span from the very simple to the progressively more complicated. Each member derived from the previous one by making well defined incremental changes. Hence, our goal is to generate a family of planar mechanisms, with members that can be as simple as a bouncing ball or as complex as a five link biped. This presentation will be the first step of this study.
Control of Film Growth in Lithium Ion Battery Packs via Switches
Authors: Moura Scott J. , Forman Joel C. , Stein Jeffrey L. , Fathy Hosam K.
Published: September 2010

Recent advances in lithium ion battery modeling suggest degradation may be reduced by permitting unequal but controlled charging of individual cells. Hence, this paper compares anode-side film formation for a standard equalization scheme versus unequal charging through switches controlled by deterministic dynamic programming (DDP) and DDP-inspired algorithms. A static map for film growth rate is derived from a first-principles battery model adopted from the electrochemical engineering literature. Using this map, we consider two cells connected in parallel via relay switches. The key results we demonstrate are: (1) Enabling unequal charging indeed reduces film buildup; (2) A near optimal control method can be implemented using heuristic rules designed from the DDP solution and convexity properties of film growth rate. Simulation results indicate that the heuristic rules achieve near optimal performance relative to the DDP solution, with significant reduction in film growth compared to charging both cells equally.
Determining Maximum Sample Period Under Performance Constraints for Sampled-Data Control Systems
Authors: Ma Jie , Chiu George T.-C.
Published: September 2010

For sampled-data control systems, where a continuous-time plant is under digital control, one of the most important design parameter is the sample rate/period. Higher sample rate typically is associated with the need of high performance components and processors that results in higher system cost. In this paper, we propose an approach to determine the slowest sample rate for a sampled-data control system that will achieve the desired performance and robustness specifications. An optimization problem can be formulated using lifting technique to parameterize sample period for a sampled-data control system. The utility of the proposed approach is numerically verified through the control systems design of the media advance system of an inkjet printer.
Design of a Small-Scale Prototype for a Stabilized Permanent Magnet Levitated Vehicle
Authors: Long Geoffrey A. , Fiske O. James , Paden Brad E.
Published: September 2010

A small-scale proof-of-concept prototype has been designed and built as the next stage in the development of a novel maglev vehicle concept. This prototype demonstrates many of the key advantages of the technology which uses permanent magnets for levitation and does not require any moving parts in a track bifurcation. Key design features and performance characteristics of the prototype are described: the control system for stable levitation, the linear synchronous motor for propulsion and the method of track switching. Alternative system configurations and other applications of the technology are also briefly discussed.
Modeling and Control of a High Pressure Combined Air/Fuel Injection System
Authors: Yong Chao , Barth Eric J.
Published: September 2010

A high pressure combined air-fuel injection system is designed and tested for an experimental free liquid-piston engine compressor. The application discussed utilizes available high pressure air from the compressor’s reservoir, and high pressure fuel to mix and then inject into a combustion chamber. This paper addresses the modeling, design and control for this particular high-pressure air-fuel injection system, which features an electronically controlled air/fuel ratio control scheme. This system consists of a fuel line and an air line, whose mass flow rates are restricted by metering valves. These two lines are connected to a common downstream tube where air and fuel are mixed. By controlling the upstream pressures and the orifice areas of the metering valves, desired A/F ratios can be achieved. The effectiveness of the proposed system is demonstrated by a lumped-parameter model in simulation and validated by experiments.
Minimization of Degradation Through Prognosis Based Control for a Damaged Aircraft Actuator
Authors: Mahulkar Vishal , Adams Douglas E. , Derriso Mark
Published: September 2010

In this paper we present a formulation of an aircraft systems model for prognosis-based control. An aircraft systems model with hydraulic actuators for control surfaces is developed in SIMULINK and is connected with a model for predicting degradation of an actuator. An LQR based feedback control is employed to compensate for changes in the plant dynamics and a feedforward controller is used to achieve better performance through set-point tracking, while taking into account the current actuator degradation rate. The advantage of the combination of feedback and feedforward control strategies is then demonstrated through reduction of degradation of the actuator while achieving a minimum loss of performance using constrained optimization.
Classification of Diesel Engine Health Using Sparse Linear Discriminant Analysis (SLDA)
Authors: Chandrachud Neha , Kakade Ravindra , Meckl Peter H. , King Galen B. , Jennings Kristofer
Published: September 2010

With requirements for on-board diagnostics on diesel engines becoming more stringent for the coming model years, diesel engine manufacturers must improve their ability to identify fault conditions that lead to increased exhaust emissions. This paper proposes a statistical classifier model to identify the state of the engine, i.e. healthy or faulty, using an optimal number of sensors based on the data acquired from the engine. The classification model proposed in this paper is based on Sparse Linear Discriminant Analysis. This technique performs Linear Discriminant Analysis with a sparseness criterion imposed such that classification, dimension reduction and feature selection are merged into one step. It was concluded that the analysis technique could produce 0% misclassification rate for the steady-state data acquired from the diesel engine using five input variables. The classifier model was also extended to transient operation of the engine. The misclassification rate in the case of transient data was reduced from 31% to 26% by using the steady-state data trained classifier using thirteen variables.
Lactococcal Abortive Infection Protein AbiV Interacts Directly with the Phage Protein SaV and Prevents Translation of Phage Proteins
Authors: Haaber Jakob , Samson Julie E. , Labrie Simon J. , Campanacci Valérie , Cambillau Christian , Moineau Sylvain , Hammer Karin
Published: September 2010

AbiV is an abortive infection protein that inhibits the lytic cycle of several virulent phages infectingLactococcus lactis, while a mutation in the phage genesavconfers insensitivity to AbiV. In this study, we have further characterized the effects of the bacterial AbiV and its interaction with the phage p2 protein SaV. First, we showed that during phage infection of lactococcal AbiV+cells, AbiV rapidly inhibited protein synthesis. Among early phage transcripts,savgene transcription was slightly inhibited while the SaV protein could not be detected. Analyses of other phage p2 mRNAs and proteins suggested that AbiV blocks the activation of late gene transcription, probably by a general inhibition of translation. Using size exclusion chromatography coupled with on-line static light scattering and refractometry, as well as fluorescence quenching experiments, we also demonstrated that both AbiV and SaV formed homodimers and that they strongly and specifically interact with each other to form a stable protein complex.
Rumen Microbial Population Dynamics during Adaptation to a High-Grain Diet
Authors: Fernando S. C. , Purvis H. T. , Najar F. Z. , Sukharnikov L. O. , Krehbiel C. R. , Nagaraja T. G. , Roe B. A. , DeSilva U.
Published: September 2010

High-grain adaptation programs are widely used with feedlot cattle to balance enhanced growth performance against the risk of acidosis. This adaptation to a high-grain diet from a high-forage diet is known to change the rumen microbial population structure and help establish a stable microbial population within the rumen. Therefore, to evaluate bacterial population dynamics during adaptation to a high-grain diet, 4 ruminally cannulated beef steers were adapted to a high-grain diet using a step-up diet regimen containing grain and hay at ratios of 20:80, 40:60, 60:40, and 80:20. The rumen bacterial populations were evaluated at each stage of the step-up diet after 1 week of adaptation, before the steers were transitioned to the next stage of the diet, using terminal restriction fragment length polymorphism (T-RFLP) analysis, 16S rRNA gene libraries, and quantitative real-time PCR. The T-RFLP analysis displayed a shift in the rumen microbial population structure during the final two stages of the step-up diet. The 16S rRNA gene libraries demonstrated two distinct rumen microbial populations in hay-fed and high-grain-fed animals and detected only 24 common operational taxonomic units out of 398 and 315, respectively. The 16S rRNA gene libraries of hay-fed animals contained a significantly higher number of bacteria belonging to the phylumFibrobacteres, whereas the 16S rRNA gene libraries of grain-fed animals contained a significantly higher number of bacteria belonging to the phylumBacteroidetes. Real-time PCR analysis detected significant fold increases in theMegasphaera elsdenii,Streptococcus bovis,Selenomonas ruminantium, andPrevotella bryantiipopulations during adaptation to the high-concentrate (high-grain) diet, whereas theButyrivibrio fibrisolvensandFibrobacter succinogenespopulations gradually decreased as the animals were adapted to the high-concentrate diet. This study evaluates the rumen microbial population using several molecular approaches and presents a broader picture of the rumen microbial population structure during adaptation to a high-grain diet from a forage diet.
Isolation of a Novel
Campylobacter jejuni
Clone Associated with the Bank Vole,
Myodes glareolus
Authors: Williams N. J. , Jones T. R. , Leatherbarrow H. J. , Birtles R. J. , Lahuerta-Marin A. , Bennett M. , Winstanley C.
Published: September 2010

Campylobacter jejuni
can be isolated from different animal hosts. Various studies have used multilocus sequence typing to look for associations between particular clones of
C. jejuni
and specific hosts. Here, we describe the isolation of a novel clone (sequence type 3704 [ST-3704]) of
C. jejuni
associated with the bank vole (
Myodes glareolus
).
Identifying Active Phage Lysins through Functional Viral Metagenomics
Authors: Schmitz Jonathan E. , Schuch Raymond , Fischetti Vincent A.
Published: September 2010

Recent metagenomic sequencing studies of uncultured viral populations have provided novel insights into the ecology of environmental bacteriophage. At the same time, viral metagenomes could also represent a potential source of recombinant proteins with biotechnological value. In order to identify such proteins, a novel two-step screening technique was devised for cloning phage lytic enzymes from uncultured viral DNA. This plasmid-based approach first involves a primary screen in which transformed
Escherichia coli
clones that demonstrate colony lysis following exposure to inducing agent are identified. This effect, which can be due to the expression of membrane-permeabilizing phage holins, is discerned by the development a hemolytic effect in surrounding blood agar. In a secondary step, the clones identified in the primary screen are overlaid with autoclaved Gram-negative bacteria (specifically
Pseudomonas aeruginosa
) to assay directly for recombinant expression of lytic enzymes, which are often encoded proximally to holins in phage genomes. As proof-of-principle, the method was applied to a viral metagenomic library constructed from mixed animal feces, and 26 actively expressed lytic enzymes were cloned. These proteins include both Gram-positive-like and Gram-negative-like enzymes, as well as several atypical lysins whose predicted structures are less common among known phage. Overall, this study represents one of the first functional screens of a viral metagenomic population, and it provides a general approach for characterizing lysins from uncultured phage.
Combined Transcriptome and Proteome Analysis ofBifidobacterium animalissubsp.lactisBB-12 Grown on Xylo-Oligosaccharides and a Model of Their Utilization
Authors: Gilad Ofir , Jacobsen Susanne , Stuer-Lauridsen Birgitte , Pedersen Martin Bastian , Garrigues Christel , Svensson Birte
Published: September 2010

Recent studies have demonstrated that xylo-oligosaccharides (XOS), which are classified as emerging prebiotics, selectively enhance the growth of bifidobacteria in general and ofBifidobacteriumanimalissubsp.lactisstrains in particular. To elucidate the metabolism of XOS in the well-documented and widely used probiotic strainB. animalissubsp.lactisBB-12, a combined proteomic and transcriptomic approach was applied, involving DNA microarrays, real-time quantitative PCR (qPCR), and two-dimensional difference gel electrophoresis (2D-DIGE) analyses of samples obtained from cultures grown on either XOS or glucose. The analyses show that 9 of the 10 genes that encode proteins predicted to play a role in XOS catabolism (i.e., XOS-degrading and -metabolizing enzymes, transport proteins, and a regulatory protein) were induced by XOS at the transcriptional level, and the proteins encoded by three of these (β-d-xylosidase, sugar-binding protein, and xylose isomerase) showed higher abundance on XOS. Based on the obtained results, a model for the catabolism of XOS in BB-12 is suggested, according to which the strain utilizes an ABC (ATP-binding cassette) transport system (probably for oligosaccharides) to bind XOS on the cell surface and transport them into the cell. XOS are then degraded intracellularly through the action of xylanases and xylosidases tod-xylose, which is subsequently metabolized by thed-fructose-6-P shunt. The findings obtained in this study may have implications for the design of a synbiotic application containing BB-12 and the XOS used in the present study.
Characterization of Bacterial Community Structure in a Drinking Water Distribution System during an Occurrence of Red Water
Authors: Li Dong , Li Zheng , Yu Jianwei , Cao Nan , Liu Ruyin , Yang Min
Published: September 2010

The role of bacteria in the occasional emergence of red water, which has been documented worldwide, has yet to be determined. To better understand the mechanisms that drive occurrences of red water, the bacterial community composition and the relative abundance of several functional bacterial groups in a water distribution system of Beijing during a large-scale red water event were determined using several molecular methods. Individual clone libraries of the 16S rRNA gene were constructed for three red water samples and one sample of normal water.
Beta
-,
Alpha
-, and
Gammaproteobacteria
comprised the major bacterial communities in both red water and normal water samples, in agreement with previous reports. A high percentage of red water clones (25.2 to 57.1%) were affiliated with or closely related to a diverse array of iron-oxidizing bacteria, including the neutrophilic microaerobic genera
Gallionella
and
Sideroxydans
, the acidophilic species
Acidothiobacillus ferrooxidans
, and the anaerobic denitrifying
Thermomonas
bacteria. The genus
Gallionella
comprised 18.7 to 28.6% of all clones in the three red water libraries. Quantitative real-time PCR analysis showed that the 16S rRNA gene copy concentration of
Gallionella
spp. was between (4.1 ± 0.9) × 10
7
(mean ± standard deviation) and (1.6 ± 0.3) × 10
8
per liter in red water, accounting for 13.1% ± 2.9% to 17.2% ± 3.6% of the total
Bacteria
spp. in these samples. By comparison, the percentages of
Gallionella
spp. in the normal water samples were 0.1% or lower (below the limit of detection), suggesting an important role of
Gallionella
spp. in the formation of red water.
Granule Formation Mechanisms within an Aerobic Wastewater System for Phosphorus Removal
Authors: Barr Jeremy J. , Cook Andrew E. , Bond Phillip L.
Published: September 2010

Granular sludge is a novel alternative for the treatment of wastewater and offers numerous operational and economic advantages over conventional floccular-sludge systems. The majority of research on granular sludge has focused on optimization of engineering aspects relating to reactor operation with little emphasis on the fundamental microbiology. In this study, we hypothesize two novel mechanisms for granule formation as observed in three laboratory scale sequencing batch reactors operating for biological phosphorus removal and treating two different types of wastewater. During the initial stages of granulation, two distinct granule types (white and yellow) were distinguished within the mixed microbial population. White granules appeared as compact, smooth, dense aggregates dominated by 97.5% “
Candidatus
Accumulibacter phosphatis,” and yellow granules appeared as loose, rough, irregular aggregates with a mixed microbial population of 12.3% “
Candidatus
Accumulibacter phosphatis” and 57.9% “
Candidatus
Competibacter phosphatis,” among other bacteria. Microscopy showed white granules as homogeneous microbial aggregates and yellow granules as segregated, microcolony-like aggregates, with phylogenetic analysis suggesting that the granule types are likely not a result of strain-associated differences. The microbial community composition and arrangement suggest different formation mechanisms occur for each granule type. White granules are hypothesized to form by outgrowth from a single microcolony into a granule dominated by one bacterial type, while yellow granules are hypothesized to form via multiple microcolony aggregation into a microcolony-segregated granule with a mixed microbial population. Further understanding and application of these mechanisms and the associated microbial ecology may provide conceptual information benefiting start-up procedures for full-scale granular-sludge reactors.
Development of a Real-Time qPCR Method for Detection and Enumeration of
Mycobacterium
spp. in Surface Water
Authors: Radomski Nicolas , Lucas Françoise S. , Moilleron Régis , Cambau Emmanuelle , Haenn Sophie , Moulin Laurent
Published: September 2010

A real-time quantitative PCR method was developed for the detection and enumeration of
Mycobacterium
spp. from environmental samples and was compared to two other methods already described. The results showed that our method, targeting 16S rRNA, was more specific than the two previously published real-time quantitative PCR methods targeting another 16S rRNA locus and the
hsp65
gene (100% versus 44% and 91%, respectively).
Molecular Cloning of Cyanobacterial Pteridine Glycosyltransferases That Catalyze the Transfer of either Glucose or Xylose to Tetrahydrobiopterin
Authors: Lee Yeol Gyun , Kim Ae Hyun , Park Mi Bi , Kim Hye-Lim , Lee Kon Ho , Park Young Shik
Published: September 2010

Here, we report cloning of cyanobacterial genes encoding pteridine glycosyltransferases that catalyze glucosyl or xylosyl transfer from UDP-sugars to tetrahydrobiopterin. The genes were cloned by PCR amplification from genomic DNA which was isolated from culture and environmental samples and overexpressed in
Escherichia coli
for an
in vitro
activity assay.
Isolation of a Novel Bacteriophage Specific for the Periodontal Pathogen
Fusobacterium nucleatum
Authors: Machuca Pamela , Daille Leslie , Vinés Enrique , Berrocal Liliana , Bittner Mauricio
Published: September 2010

Fusobacterium nucleatum
is a periodontal pathogen that has been directly associated with the development and progression of periodontal disease, a widespread pathology that affects the support tissues of the tooth. We isolated a new bacteriophage (FnpΦ02) that specifically infects this bacterium. Transmission electron microscopy showed that the virion is composed of an icosahedral head and a segmented tail. The size of the phage genome was estimated to be approximately 59 kbp of double-stranded DNA. The morphological features and the genetic characteristics suggest that FnpΦ02 is part of the
Siphoviridae
family. Using one-step growth and adsorption experiments, the latent period, burst size, and adsorption rate were estimated to be 15 h, 100 infectious units per cell, and 7.5 × 10
−10
ml min
−1
, respectively. A small fragment of phage DNA was cloned and sequenced, showing 93% nucleotide identity with the phage PA6 of
Propionibacterium acnes
and amino acid identity with fragments of two proteins (Gp3 and Gp4) of this phage. To our knowledge, FnpΦ02 is the first phage described to infect
Fusobacterium nucleatum
and provides the base for future exploration of phages in the control of periodontal disease.
Stable, Site-Specific Fluorescent Tagging Constructs Optimized for
Burkholderia
Species
Authors: Norris Michael H. , Kang Yun , Wilcox Bruce , Hoang Tung T.
Published: September 2010

Several vectors that facilitate stable fluorescent labeling of
Burkholderia pseudomallei
and
Burkholderia thailandensis
were constructed. These vectors combined the effectiveness of the mini-Tn
7
site-specific transposition system with fluorescent proteins optimized for
Burkholderia
spp., enabling bacterial tracking during cellular infection.
Activation of Two Different Resistance Mechanisms inSaccharomyces cerevisiaeupon Exposure to Octanoic and Decanoic Acids
Authors: Legras J. L. , Erny C. , Le Jeune C. , Lollier M. , Adolphe Y. , Demuyter C. , Delobel P. , Blondin B. , Karst F.
Published: September 2010

Medium-chain fatty acids (octanoic and decanoic acids) are well known as fermentation inhibitors. During must fermentation, the toxicity of these fatty acids is enhanced by ethanol and low pH, which favors their entrance in the cell, resulting in a decrease of internal pH. We present here the characterization of the mechanisms involved in the establishment of the resistance to these fatty acids. The analysis of the transcriptome response to the exposure to octanoic and decanoic acids revealed that two partially overlapping mechanisms are activated; both responses share many genes with an oxidative stress response, but some key genes were activated differentially. The transcriptome response to octanoic acid stress can be described mainly as a weak acid response, and it involves Pdr12p as the main transporter. The phenotypic analysis of knocked-out strains confirmed the role of the Pdr12p transporter under the control ofWAR1but also revealed the involvement of the Tpo1pmajorfacilitatorsuperfamily proteins (MFS) transporter in octanoic acid expulsion. In contrast, the resistance to decanoic acid is composite. It also involves the transporter Tpo1p and includes the activation of several genes of the beta-oxidation pathway and ethyl ester synthesis. Indeed, the induction ofFAA1andEEB1, coding for a long-chain fatty acyl coenzyme A synthetase and an alcohol acyltransferase, respectively, suggests a detoxification pathway through the production of decanoate ethyl ester. These results are confirmed by the sensitivity of strains bearing deletions for the transcription factors encoded byPDR1,STB5,OAF1, andPIP2genes.