bluuebunny/crossref_metadata_2025 huggingface dataset:
Study and Application of Reinforcement Learning in Cooperative Strategy of the Robot Soccer Based on BDI Model
Authors: Qi Guo , Bo-ying Wu
Published: March 2012

The dynamic cooperation model of multi-Agent is formed by combining reinforcement learning with BDI model. In this model, the concept of the individual optimization loses its meaning, because the repayment of each Agent dose not only depend on itsself but also on the choice of other Agents. All Agents can pursue a common optimum solution and try to realize the united intention as a whole to a maximum limit. The robot moves to its goal, depending on the present positions of the other robots that cooperate with it and the present position of the ball. One of these robots cooperating with it is controlled to move by man with a joystick. In this way, Agent can be ensured to search for each state-action as frequently as possible when it carries on choosing movements, so as to shorten the time of searching for the movement space so that the convergence speed of reinforcement learning can be improved. The validity of the proposed cooperative strategy for the robot soccer has been proved by combining theoretical analysis with simulation robot soccer match (11vs11).
A Sensor Based Navigation Algorithm for a Mobile Robot using the DVFF Approach
Authors: DJEKOUNE A. OUALID , ACHOUR KARIM , TOUMI REDOUANE
Published: March 2012

Often autonomous mobile robots operate in environment for which prior maps are incomplete or inaccurate. They require the safe execution for a collision free motion to a goal position. This paper addresses a complete navigation method for a mobile robot that moves in unknown environment. Thus, a novel method called DVFF combining the Virtual Force Field (VFF) obstacle avoidance approach and global path planning based on D* algorithm is proposed. While D* generates global path information towards a goal position, the VFF local controller generates the admissible trajectories that ensure safe robot motion. Results and analysis from a battery of experiments with this new method implemented on a ATRV2 mobile robot are shown.
A Combination of Terrain Prediction and Correction for Search and Rescue Robot Autonomous Navigation
Authors: Guo Yan , Song Aiguo , Bao Jiatong , Hongru Tang , Cui Jianwei
Published: March 2012

This paper presents a novel two-step autonomous navigation method for search and rescue robot. The algorithm based on the vision is proposed for terrain identification to give a prediction of the safest path with the support vector regression machine (SVRM) trained off-line with the texture feature and color features. And correction algorithm of the prediction based the vibration information is developed during the robot traveling, using the judgment function given in the paper. The region with fault prediction will be corrected with the real traversability value and be used to update the SVRM. The experiment demonstrates that this method could help the robot to find the optimal path and be protected from the trap brought from the error between prediction and the real environment.
Analysis on Self-Morphing Process of Self-Reconfigurable Modular Robot
Authors: Fei Yanqiong , Zhu Yueliang , Xia Ping
Published: March 2012

The self-reconfigurable modular robot consists of many identical modules. By connecting to/disconnecting from other modules, the whole structure of the robot can transform into arbitrary other configurations. First, the lattice-type self-reconfigurable modular robot is proposed and its disconnected/connected mechanism is analyzed, which can finish self-morphing action. Second, the basic configuration of the module is analyzed with the eigenvector matrix. The motion rules are proposed. Third, the possible motion space is described with the geometric feature of modules which is effective for performing the self-morphing process. Then, the self-morphing motion process is described with the driving function and the adjacency matrix which is useful to solve the computation problem and optimize the motion paths of the robot during the self-reconfigurable morphing process. Final, an experiment of three-module motion and a simulation of multi-module's self-morphing process are shown to prove that the above analyses are effective.
Extracting the Prevailed Patterns in Recognizing the Picture by the Human Vision
Authors: Kamrani Ehsan
Published: March 2012

We have tried to present the most matched approaches with which the vision dose through numerous studying the segment fields and recognizing the picture. Here we define external pictures features as the prevailed picture features and then extract the locust point of minus decline and among these points. Of minus decline and among these points we have defined the points which match with the human vision specifications according to the defined factors in this research such as clarification sharpness roundness and adjacency and used them as copied systems. We have reviewed our proposed patterns for truth, correctness and validity through performing two empirical tests.
Robust Neural Network Control of Electrically Driven Robot Manipulator Using Backstepping Approach
Authors: Shafiei Seyed Ehsan , Soltanpour Mohammad Reza
Published: March 2012

A novel approach to neural network based tracking-control of robot manipulator including actuator dynamics is proposed by using of backstepping method. A simple two-step backstepping is considered for an n-link robotic system, and a feedforward neural controller is designed at second step where structured and unstructured uncertainties in robot dynamics and actuator model are approximated by this neural controller. Bounds of network reconstruction error and other imprecisions are estimated adaptively and for compensating them, a robust control signal is added and modified. Stability analysis is performed by the Lyapunov direct method and performance efficiency of the proposed controller is justified by the simulations.
Coordinated Formation Control of Multiple Autonomous Underwater Vehicles for Pipeline Inspection
Authors: Xiang Xianbo , Jouvencel Bruno , Parodi Olivier
Published: March 2012

This paper addresses the control problem of inspecting underwater pipeline on the seabed, with coordinated multiple autonomous underwater vehicles in a formation. Based on the leader-follower strategy, the dedicated nonlinear path following controller is rigorously built on Lyapunov-based design, driving a fleet of vehicles onto assigned parallel paths elevated and offset from the underwater pipeline, while keeping a triangle formation to capture complete 3D images for inspection. Due to the spatial-temporal decoupling characteristics of individual path following controller, the velocities of the followers can be adapted in the coordinated control level, only relying on the information of generalized along-path length from the leader, in order to build the desired formation. Thus, the communication variable broadcast from the leader is kept to a minimum, which is feasible under the severely constraints of acoustic communication bandwidth. Simulation results illustrate the efficiency of coordinated formation controller proposed for underwater pipeline inspection.
Learning Long-range Terrain Perception for Autonomous Mobile Robots
Authors: Wang Mingjun , Zhou Jun , Tu Jun , Liu Chengliang
Published: March 2012

Long-range terrain perception has a high value in performing efficient autonomous navigation and risky intervention tasks for field robots, such as earlier recognition of hazards, better path planning, and higher speeds. However, Stereo-based navigation systems can only perceive near-field terrain due to the nearsightedness of stereo vision. Many near-to-far learning methods, based on regions' appearance features, are proposed to predict the far-field terrain. We proposed a statistical prediction framework to enhance long-range terrain perception for autonomous mobile robots. The main difference between our solution and other existing methods is that our framework not only includes appearance features as its prediction basis, but also incorporates spatial relationships between terrain regions in a principled way. The experiment results show that our framework outperforms other existing approaches in terms of accuracy, robustness and adaptability to dynamic unstructured outdoor environments.
A Multi-Robot Control Architecture for Fault-Tolerant Sensor-Based Coverage
Authors: Ozkan Metin , Kirlik Gokhan , Parlaktuna Osman , Yufka Alpaslan , Yazici Ahmet
Published: March 2012

Sensor-based coverage problems have many applications such as patrolling, search-rescue, and surveillance. Using multi-robot team increases efficiency by reducing completion time of a sensor-based coverage task. Robustness to robot failures is another advantage of using multiple robots for coverage. Although there are many works to increase the efficiency of coverage methods, there are few works related to robot failures in the literature. In this paper, fault-tolerant control architecture is proposed for sensor-based coverage. Robot failures are detected using the heartbeat strategy. To show the effectiveness of the proposed approach, experiments are conducted using P3-DX mobile robots both in laboratory and simulation environment.
Hidden Markov Model Based Visual Perception Filtering in Robotic Soccer
Authors: Kavaklioglu Can , Akin H. Levent
Published: March 2012

Autonomous robots can initiate their mission plans only after gathering sufficient information about the environment. Therefore reliable perception information plays a major role in the overall success of an autonomous robot. The Hidden Markov Model based post-perception filtering module proposed in this paper aims to identify and remove spurious perception information in a given perception sequence using the generic meta-pose definition. This method allows representing uncertainty in more abstract terms compared to the common physical representations. Our experiments with the four legged AIBO robot indicated that the proposed module improved perception and localization performance significantly.
An Autonomous Mobile Robotic System for Surveillance of Indoor Environments
Authors: Di Paola Donato , Milella Annalisa , Cicirelli Grazia , Distante Arcangelo
Published: March 2012

The development of intelligent surveillance systems is an active research area. In this context, mobile and multi-functional robots are generally adopted as means to reduce the environment structuring and the number of devices needed to cover a given area. Nevertheless, the number of different sensors mounted on the robot, and the number of complex tasks related to exploration, monitoring, and surveillance make the design of the overall system extremely challenging. In this paper, we present our autonomous mobile robot for surveillance of indoor environments. We propose a system able to handle autonomously general-purpose tasks and complex surveillance issues simultaneously. It is shown that the proposed robotic surveillance scheme successfully addresses a number of basic problems related to environment mapping, localization and autonomous navigation, as well as surveillance tasks, like scene processing to detect abandoned or removed objects and people detection and following. The feasibility of the approach is demonstrated through experimental tests using a multisensor platform equipped with a monocular camera, a laser scanner, and an RFID device. Real world applications of the proposed system include surveillance of wide areas (e.g. airports and museums) and buildings, and monitoring of safety equipment.
A New Approach of Multi-Robot Cooperative Pursuit Based on Association Rule Data Mining
Authors: Li Jun , Pan Qishu , Hong Bingrong
Published: March 2012

An approach of cooperative hunting for multiple mobile targets by multi-robot is presented, which divides the pursuit process into forming the pursuit teams and capturing the targets. The data sets of attribute relationship is built by consulting all of factors about capturing evaders, then the interesting rules can be found by data mining from the data sets to build the pursuit teams. Through doping out the positions of targets, the pursuit game can be transformed into multi-robot path planning. Reinforcement learning is used to find the best path. The simulation results show that the mobile evaders can be captured effectively and efficiently, and prove the feasibility and validity of the given algorithm under a dynamic environment.
JL-2: A Mobile Multi-robot System with Docking and Manipulating Capabilities
Authors: Wang Wei , Yu Wenpeng , Zhang Houxiang
Published: March 2012

This paper presents a new version of the JL series reconfigurable multi-robot system called JL-2. By virtue of the docking manipulator composed of a parallel mechanism and a cam gripper, every mobile robot in the JL-2 system is able to not only perform tasks in parallel, e.g. moving and grasping, but also dock with each other even if there are large misalignments between two robots. A motorized spherical joint is formed between two docked robots to enhance the locomotion capability of JL-2. To fulfill the demands of reconfiguration, a distributed control system and sonar based docking guidance system are designed for the JL-2 prototype. Based on the above design, the JL-2 prototype has been built and successfully demonstrated to confirm the validity and functionality of the proposed capabilities.
A Method for Detecting Breaches and New Objects in Multiple Outdoor Images
Authors: Tanjung Guntur , Lu Tien-Fu , Lozo Peter
Published: March 2012

This paper presents a new automated change detection method for detecting breaches in the integrity of and attached objects in front of fence wires in multiple outdoor images of the same scene containing fence wires acquired by a mobile camera from slightly different viewing positions, angles and at different times. To detect significant changes, edges of fence wires firstly have to be extracted from multiple outdoor images using a combination of the Sobel detector and an adaptive thresholding technique. Secondly, morphological operations such as dilation and erosion are applied into binary images produced by the previous process in enhancing the binary images. Next, an area-based algorithm is applied to enhanced binary images in separating small and big objects based on their average areas determined once in the calibration process. Finally, objects that survive are then fed into a fuzzy inference system in calculating their possibility values. Based on these possibility values, the survived objects can be classified as significant or unimportant changes. Experimental results demonstrate that the method has a high success rate (94.12%) in detecting true positives in these kinds of multiple outdoor images.
Development of Biomedical Microrobot for Intravascular Therapy
Authors: Park Sukho , Cha Kyoungrae , Park Jongoh
Published: March 2012

Recently, coronary artery disease such as angina pectoris and myocardial infarction has become the major causes of death. As a method of medical treatment for the disease, the pharmacological approaches and the surgical operations are executed. Especially, percutaneous coronary intervention (PCI) using catheters are the mostly preferred treatment for coronary artery diseases. The PCI technologies are advanced and the various useful devices are developed and utilized. However, some clinical operations such as the treatment of chronic total occlusion (CTO) remain a limitation of PCI and a major challenge. As robot-assisted coronary interventions, this paper proposes the microrobot for the therapy of CTO. The microrobot consists of the functions of position recognition, locomotion and treatment in the blood vessels. The functions of the microrobot can be validated through in-vitro & in-vivo experiments. The innovative technologies and surgical concept using the microrobot are currently being developed.
On the Improvement of Multi-Legged Locomotion over Difficult Terrains Using a Balance Stabilization Method
Authors: Asif Umar , Iqbal Javaid
Published: March 2012

This paper deals with the real-time walking of a multi-legged robot over difficult terrains using a balance stabilization method in order to achieve a fast speed and robust locomotion with minimal tracking errors. The stabilization method is described through a ZMP-based online pattern-generation scheme inspired by bio-mimetic stepping leg transferences with an active balance control so as to reduce the propagation of instability while performing rapid stepping actions for a fast walking gait in the presence of external disturbances. The proposed control system uses a force-position controller [14] which takes impact dynamics into consideration to compensate for the effect of external perturbations during walking by estimating impulsive forces in real-time. Using the proposed stabilization method, the robot plans appropriate footholds on the ground in order to achieve a reasonable average walking speed over difficult terrains in a natural environment. The success and performance of the proposed method is realized through dynamic simulations and real-world experiments using a six-legged hexapod robot.
Autonomous Deployment and Restoration of Sensor Network using Mobile Robots
Authors: Suzuki Tsuyoshi , Sugizaki Ryuji , Kawabata Kuniaki , Hada Yasushi , Tobe Yoshito
Published: March 2012

This paper describes an autonomous deployment and restoration of a Wireless Sensor Network (WSN) using mobile robots. The authors have been developing an information-gathering system using mobile robots and WSNs in underground spaces in post-disaster environments. In our system, mobile robots carry wireless sensor nodes (SN) and deploy them into the environment while measuring Received Signal Strength Indication (RSSI) values to ensure communication, thereby enabling the WSN to be deployed and restored autonomously. If the WSN is disrupted, mobile robots restore the communication route by deploying additional or alternate SNs to suitable positions. Utilizing the proposed method, a mobile robot can deploy a WSN and gather environmental information via the WSN. Experimental results using a verification system equipped with a SN deployment and retrieval mechanism are presented.
Fuzzy/Kalman Hierarchical Horizontal Motion Control of Underactuated ROVs
Authors: Raimondi Francesco M. , Melluso Maurizio
Published: March 2012

A new closed loop fuzzy motion control system including on-line Kalman's filter (KF) for the two dimensional motion of underactuated and underwater Remotely Operated Vehicle (ROV) is presented. Since the sway force is unactuated, new continuous and discrete time models are developed using a polar transformation. A new hierarchical control architecture is developed, where the high level fuzzy guidance controller generates the surge speed and the yaw rate needed to achieve the objective of planar motion, while the low level controller gives the thruster surge force and the yaw torque control signals. The Fuzzy controller ensures robustness with respect to uncertainties due to the marine environment, forward surge speed and saturation of the control signals. Also Lyapunov's stability of the motion errors is proved based on the properties of the fuzzy maps. If Inertial Measurement Unit data (IMU) is employed for the feedback directly, aleatory noises due to accelerometers and gyros damage the performances of the motion control. These noises denote a kind of non parametric uncertainty which perturbs the model of the ROV. Therefore a KF is inserted in the feedback of the control system to compensate for the above uncertainties and estimate the feedback signals with more precision.
A Algorithm for the Vehicle Problem
Authors: Ezzatneshan Aziz
Published: March 2012

In this paper, we propose a hybrid ACO algorithm for solving vehicle routing problem (VRP) heuristically in combination with an exact In the basic VRP, geographically scattered customers of known demand are supplied from a single depot by a fleet of identically capacitated vehicles. The intuition of the proposed algorithm is that nodes which are near to each other will probably belong to the same branch of the minimum spanning tree of the problem graph and thus will probably belong to the same route in VRP. Given a clustering of client nodes, the solution is to find a route in these clusters by using ACO with a modified version of transition rule of the ants. At the end of each iteration, ACO tries to improve the quality of solutions by using a local search algorithm, and update the associated weights of the graph arcs.
Visual SLAM and Moving-object Detection for a Small-size Humanoid Robot
Authors: Wang Yin-Tien , Lin Ming-Chun , Ju Rung-Chi
Published: March 2012

In the paper, a novel moving object detection (MOD) algorithm is developed and integrated with robot visual Simultaneous Localization and Mapping (vSLAM). The moving object is assumed to be a rigid body and its coordinate system in space is represented by a position vector and a rotation matrix. The MOD algorithm is composed of detection of image features, initialization of image features, and calculation of object coordinates. Experimentation is implemented on a small-size humanoid robot and the results show that the performance of the proposed algorithm is efficient for robot visual SLAM and moving object detection.
Performance of the Improvements of the CAESAR Robot
Authors: Stopforth Riaan , Bright Glen , Harley Ronald
Published: March 2012

Robots are able to enter concealed and unstable environments inaccessible to rescuers. Previous Urban Search And Rescue (USAR) robots have experienced problems with malfunction of communication systems, traction systems, control and telemetry. These problems were accessed and improved in developing a prototype robot called CAESAR, which is an acronym for Contractible Arms Elevating Search And Rescue. Problems encountered with previous USAR robots are discussed. The mechanical, sensory and communication systems that were used on CAESAR are briefly explained. Each system was separately tested by performed experiments. Results of field tests and the robot performance experienced during a disaster scenario that was created are discussed. The capabilities of CAESAR are explained in these tests to determine if some of the problems experienced previously are solved.
Motion Planning for Humanoid Robot Based on Hybrid Evolutionary Algorithm
Authors: Qiu-bo ZHONG , Song-hao PIAO , Chao GAO
Published: March 2012

In this paper, online gait control system is designed for walking-up-stairs movement according to the features of humanoid robot, the hybrid evolutionary approach based on neural network optimized by particle swarm is employed for the offline training of the movement process, and the optimal gait of the stability is generated. Additionally, through embedded monocular vision, on-site environmental information is collected as neural network input, so necessary joint trajectory is output for the movement. Simulations and experiment testify the efficiency of the method.
Metathesis Polymerization
Authors: Nuyken Oskar , Schneider Martin , Frenzel Ulrich
Published: March 2012

Especially since the turn of the century, metathesis has become one of the most attractive developments in organic synthesis, particularly for the synthesis of polymers. A major reason for this has been the discovery of a wide range of new catalysts. The development of Ru‐based catalysts has opened up new avenues of synthesis due to their functional group tolerance. It this review, homogeneous, heterogeneous, and immobilized catalysts are described. It is shown that13C NMR spectroscopy is a valuable tool for the evaluation of the microstructure of polymers synthesized from bicyclic monomers, such as norbornene and its derivatives. Acyclic diene metathesis polymerization (ADMET) is also addressed. Indeed, the intermolecular reaction of α,ω‐dienes yielding ethene has become increasingly important over the past 10 years. Degradation of polymers via cross‐metathesis of unsaturated polymers with olefins can be used for analytical purposes and for the design of tailor‐made polymers. This article also discuses about the growing interest in terminally functionalized polymers and oligomers. Synthetic strategies based on metathesis reactions are discussed in some detail. The section titled Macromolecular Engineering summarizes trends in polymer chemistry involving metathesis polymerization combined with other chain growth mechanisms to synthesize block and graft copolymers with novel molecular structures. In addition, this article details synthetic routes to advanced materials based on ring‐opening metathesis polymerization (ROMP). Furthermore, some of the industrial polymers synthesized via ROMP are introduced and discussed in some detail. This review concludes with a discussion on mono‐, bi‐, and tri‐cyclic monomers and their ring‐opening polymerizations.
Single‐Site Catalysts
Authors: Heurtefeu Bertrand , Vaultier Florent , Leino Reko , Boisson Christophe , Cramail Henri
Published: March 2012

The recent rapid development of organometallic single‐site catalysts (SSCs) has revolutionized polyolefin research and permitted the production of new specialty polymers and commodity polyolefins with improved properties. These well‐defined catalyst systems generally consist of a transition metal atom, such as titanium, zirconium, hafnium, iron, nickel, or palladium, complexed with an organic ligand set and an initiating group. In most cases, activation with methylaluminoxane or compounds bearing a weakly coordinating anions generates cationic‐active species responsible for olefin coordination and polymer chain growth. Representative examples of SSCs include the bis(cyclopentadienyl) or bis(phenoxyimine)‐type group 4 catalysts as well as the diimine complexes of nickel and palladium. By variation of the organic ligand and thus the steric and electronic environment of the metal center, these catalysts can be tailored to control the olefin polymerization reaction in an unprecedented fashion. Almost any vinyl monomer, irrespective of molecular weight or steric hindrance, can be polymerized by choosing the proper catalyst. Virtually all feasible poly(α‐olefin) microstructures ranging from atactic to isotactic, hemiisotactic, syndiotactic, and stereoblock polymers can be produced by rational modification of the catalyst structure. Functional monomers are readily copolymerized with the less oxophilic late transition metal catalysts. Entirely new materials, not accessible with traditional Ziegler–Natta catalysts, have emerged, including high melting syndiotactic polystyrene and cycloaliphatic polymers. This article provides a broad overview of SSCs and their application in olefin polymerization. Evolution and classification of SSCs, polymerization of ethylene, propylene, as well as functional olefins, macromolecular architecture bearing polyolefin blocks are covered. Finally, heterogenization of SSCs for use in industrial processes is described.
DNA
Immobilization
Authors: Wittmann Christine , Marquette Christophe
Published: March 2012

Immobilized DNA is required for the development of DNA chips and arrays, DNA sensors, or other sensing devices including microfluidics, in addition to gene delivery devices. The broad application range for all of these DNA‐based systems is to a major extent found in the medical area, using the devices also in DNA sequencing and furthermore for food and environmental analyses. Therefore, strategies for DNA immobilization are described in this article, with focus on immobilization chemistry. Depending on the different surfaces, various immobilization techniques (e.g. via physical adsorption, covalent, affinity binding, and matrix entrapment) were developed and optimized, which are described for carbonaceous materials (e.g. carbon nanotubes), silica and silicon surfaces, gold surfaces, the same as for more recently complex biocompatible surfaces (e.g. polymeric gels). The ‘top‐down techniques’ can be distinguished from the ‘bottom‐up’ techniques started in the very beginning of DNA chip development. More recently, surfaces such as stents or biocompatible transplants are on focus to generate therapeutic devices. In the future, the power of DNA as a self‐assembling material could be used to combine both the ‘bottom‐up’ and ‘top‐down’ strategies to generate complex nanostructures with multifunctional applications (e.g. three‐dimensional DNA ‘origami’). Overall, the main aim of this article is to provide an overview of the methods currently used for DNA immobilization regarding the broad variety of the above mentioned potential applications.
Stable Isotope Analysis: Hair and Nails
Authors: Meier‐Augenstein Wolfram , Kemp Helen F
Published: March 2012

While bone and teeth provide a long‐term stable isotope record of a person's life history measured in years (seeStabel Isotope Analysis: Bone and Teeth), stable isotope profiles of hair and nail can yield information on a person's recent life circumstance up to 15 months into a person's past. Since hair and nail samples can be collected noninvasively, stable isotope profiles of these tissues may also be used to reveal information on recent geographic movement in living people. This information may prove useful to check on the veracity of a suspect's statement about their recent geographic movements.
Image Comparison: Facial, Photographic
Authors: Davis Josh P.
Published: March 2012

Photographic facial image comparison analysis refers to techniques designed to determine whether two or more photographic images depict the same person or not. One of the images will normally either be the suspect in a police investigation, or the defendant in court. Comparison crime scene evidence will often be images acquired from sources such as closed circuit television cameras (CCTV). There are three primary techniques used by expert witnesses to present opinion evidence of identity in court. With photoanthropometric analysis, the proportional distances and angles between specified facial features visible in photographs are measured and compared across evidence. With morphological comparison analysis, facial features are visually inspected and classified into predetermined categories. Finally, with photographic superimposition analysis, one photograph or video still is superimposed over a second, to perform a series of visual inspections. The forensic reliability of each method with two‐dimensional photographs is questionable, particularly, if the image quality is poor, or the facial viewpoints in different images do not match. Furthermore, expert opinion of identity evidence is rarely accompanied with statistical margins of error, or the probability that images depict two different individuals. Nevertheless, recent innovations using three‐dimensional image capture technology have suggested that in the future, there may be improvements in the reliability of photographic facial image comparison techniques.
Sleep and EEG Phenotyping in Mice
Authors: Mang Géraldine Morgane , Franken Paul
Published: March 2012

Although alternative, noninvasive methods are being developed, current research on rodent sleep still almost exclusively relies on recording the electroencephalogram (EEG). EEG provides information about the electrical activity of the brain and is, in combination with the electromyogram (EMG), primarily used to distinguish the different sleep and wake states. This unit describes the technique used to record EEG and EMG signals in freely moving mice, under standard laboratory conditions or specific experimental protocols such as sleep deprivation (SD). In addition to its use to determine behavioral state, the EEG contains a wealth of information concerning rhythmic brain activity that can be extracted using signal analysis tools. We will describe the protocol for implantation of EEG and EMG electrodes, provide examples of experimental designs, and discuss data acquisition and analysis illustrating the type of information that can be obtained from the EEG in mice. Curr. Protoc. Mouse Biol. 2:54‐74 © 2012 by John Wiley & Sons, Inc.
Acoustic Startle Reflex and Prepulse Inhibition
Authors: Ouagazzal Abdel Mottalib , Meziane Hamid
Published: March 2012

The completion of genome sequencing in humans and mice has opened new opportunities to study the relationship between gene expression and behavior and for development of novel therapeutic approaches for brain diseases. Recently, several international programs for large‐scale production and phenotyping of genetically modified mice have been launched (e.g., EUCOMM, EUMODIC, IMPC), and comprehensive high‐throughput behavioral phenotyping strategies have been developed (EUMORPHIA). In this context, startle reflex represents an important research tool for studying the impact of genetic manipulations not only on sensory processes but also on complex brain functions such as cognition, emotions, and movement control. In this unit, step‐by‐step protocols for measurement of acoustic startle reactivity and prepulse inhibition of startle in mice are described, and supporting experimental data presented. Curr. Protoc. Mouse Biol. 2:25‐35 © 2012 by John Wiley & Sons, Inc.
Superhard Materials
Authors: Mohammadi Reza , Kaner Richard B.
Published: March 2012

Materials possessing superior hardness can be divided into two main categories: ultra‐hard and superhard. Diamond and cubic boron nitride (
c
‐BN) are considered ultra‐hard with hardness values ranging from 70 to 110 and 45 to 60 GPa, respectively. All other materials with a hardness of greater than 40 GPa are called superhard. Ultra‐hard materials are traditionally used in industrial applications including cutting tools and wear‐protecting surfaces. However, diamond is not a good choice for high‐speed cutting of ferrous‐based alloys because of its graphitization on the material's surface and formation of brittle carbides, which leads to poor cutting performance. In addition, the synthesis of both diamond and
c
‐BN requires high pressure‐high temperature conditions. Therefore, a great deal of effort has been made to address these shortcomings and to find a reliable substitute for these ultra‐hard materials. Studies have been directed toward the development of either main group compounds (such as SiC and Si
3
N
4
) or transition‐metal compounds (such as WC and HfN). Unfortunately, most of these compounds are not superhard (e.g., WC, SiC) or their synthesis needs high pressures and high temperatures (e.g., Si
3
N
4
) that entails expensive equipment and processing costs. Among these compounds, dense transition‐metal diborides have exhibited very promising mechanical properties including great hardness, while remaining relatively easy to synthesize at ambient pressure, and may form the next generation of cutting tools and abrasion‐resistant coatings. In this article, we will review the recent advancements in synthesis and characterization of single‐phase ultra‐hard and superhard materials, with a special focus on transition‐metal diborides. We hope that this article may shed light on the inconsistencies of some of the data reported in the literature and make comparisons among materials possessing great hardness easier. Except for some rare cases, the hardness of thin films and composites will not be covered here and left for a future study.
Time‐dependent increased risk for serious infection from continuous use of tumor necrosis factor antagonists over three years in patients with rheumatoid arthritis
Authors: Sakai Ryoko , Komano Yukiko , Tanaka Michi , Nanki Toshihiro , Koike Ryuji , Nagasawa Hayato , Amano Koichi , Nakajima Atsuo , Atsumi Tatsuya , Koike Takao , Ihata Atsushi , Ishigatsubo Yoshiaki , Saito Kazuyoshi , Tanaka Yoshiya , Ito Satoshi , Sumida Takayuki , Tohma Shigeto , Tamura Naoto , Fujii Takao , Sugihara Takahiko , Kawakami Atsushi , Hagino Noboru , Ueki Yukitaka , Hashiramoto Akira , Nagasaka Kenji , Miyasaka Nobuyuki , Harigai Masayoshi ,   for the Real Study Group
Published: March 2012

Objective

To investigate associations between continuous treatments with tumor necrosis factor (TNF) antagonists and risk for developing serious infections (SIs) over 3 years in Japanese patients with rheumatoid arthritis (RA) enrolled in the Registry of Japanese RA Patients for Long‐Term Safety (REAL) database.

Methods

We analyzed 727 RA patients who had started either infliximab or etanercept (the anti‐TNF group; 1,480.1 patient‐years [PY]) and 571 RA patients who had started conventional nonbiologic disease‐modifying antirheumatic drugs (the unexposed group; 1,104.1 PY) at the time of enrollment in the REAL. We assessed the occurrence of SIs within a 3‐year observation period, including the period after switching to other TNF antagonists, and all SIs, unlimited to the first one in each patient as reported in other studies, to evaluate the real safety of TNF antagonists in daily practice.

Results

The incidence rate of SIs per 100 PY was 5.54 (95% confidence interval [95% CI] 4.44–6.84) in the anti‐TNF group and 2.72 (95% CI 1.87–3.83) in the unexposed group. Poisson regression analysis revealed that the relative risk (RR) of continuous use of TNF antagonists for SIs after adjusting for baseline and time‐dependent covariates was significantly elevated both overall (1.97, 95% CI 1.25–3.19) and for the first year (2.40, 95% CI 1.20–5.03), but not for the second and third years combined (1.38, 95% CI 0.80–2.43). The adjusted RR for SIs of etanercept compared to infliximab was not significantly elevated.

Conclusion

Continuous anti‐TNF therapy was significantly associated with increased risks for developing SIs during, but not after, the first year.
Sources of Hysteresis in Carbon Nanotube Field‐Effect Transistors and Their Elimination Via Methylsiloxane Encapsulants and Optimized Growth Procedures
Authors: Jin Sung Hun , Islam Ahmad E. , Kim Tae‐il , Kim Ji‐hun , Alam Muhammad A. , Rogers John A.
Published: March 2012

The origins of gate‐induced hysteresis in carbon nanotube field‐effect transistors are explained and techniques to eliminate this hysteresis with encapsulating layers of methylsiloxane and modified processes for nanotube growth are reported. A combined experimental and theoretical analysis of the dependence of hysteresis on the gate voltage sweep‐rate reveals the locations, types, and densities of defects that contribute to hysteresis. Devices with designs that eliminate these defects exhibit more than ten times reduction in hysteresis compared to conventional layouts. Demonstrations in individual transistors that use both networks and arrays of nanotubes, and in simple logic gates built with these devices, illustrate the utility of the proposed approaches.
Correlating Emissive Non‐Geminate Charge Recombination with Photocurrent Generation Efficiency in Polymer/Perylene Diimide Organic Photovoltaic Blend Films
Authors: Keivanidis Panagiotis E. , Kamm Valentin , Zhang Weimin , Floudas George , Laquai Frédéric , McCulloch Iain , Bradley Donal D. C. , Nelson Jenny
Published: March 2012

Evidence for a correlation between the dynamics of emissive non‐geminate charge recombination within organic photovoltaic (OPV) blend films and the photocurrent generation efficiency of the corresponding blend‐based solar cells is presented. Two model OPV systems that consist of binary blends of electron acceptor N′‐bis(1‐ethylpropyl)‐3,4,9,10‐perylene tetracarboxy diimide (PDI) with either poly(9,9‐dioctylfluorene‐co‐benzothiadiazole) (F8BT) or poly(9,9‐dioctylindenofluorene‐co‐benzothiadiazole) (PIF8BT) as electron donor are studied. For the F8BT:PDI and PIF8BT:PDI devices photocurrent generation efficiency is shown to be related to the PDI crystallinity. In contrast to the F8BT:PDI system, thermal annealing of the PIF8BT:PDI layer at 90 °C has a positive impact on the photocurrent generation efficiency and yields a corresponding increase in PL quenching. The devices of both blends have a strongly reduced photocurrent on higher temperature annealing at 120 °C. Delayed luminescence spectroscopy suggests that the improved efficiency of photocurrent generation for the 90 °C annealed PIF8BT:PDI layer is a result of optimized transport of the photogenerated charge‐carriers as well as of enhanced PL quenching due to the maintenance of optimized polymer/PDI interfaces. The studies propose that charge transport in the blend films can be indirectly monitored from the recombination dynamics of free carriers that cause the delayed luminescence. For the F8BT:PDI and PIF8BT:PDI blend films these dynamics are best described by a power‐law decay function and are found to be temperature dependent.
Incipient Ferroelectricity in Al‐Doped HfO2 Thin Films
Authors: Mueller Stefan , Mueller Johannes , Singh Aarti , Riedel Stefan , Sundqvist Jonas , Schroeder Uwe , Mikolajick Thomas
Published: March 2012

Incipient ferroelectricity is known to occur in perovskites such as SrTiO3, KTaO3, and CaTiO3. For the first time it is shown that the intensively researched HfO2 thin films (16 nm) also possess ferroelectric properties when aluminium is incorporated into the host lattice. Polarization measurements on Al:HfO2 based metal–insulator–metal capacitors show an antiferroelectric‐to‐ferroelectric phase transition depending on annealing conditions and aluminium content. Structural investigation of the electrically characterized capacitors by grazing incidence X‐ray diffraction is presented in order to gain further insight on the potential origin of ferroelectricity. The non‐centrosymmetry of the elementary cell, which is essential for ferroelectricity, is assumed to originate from an orthorhombic phase of space group Pbc21 stabilized for low Al doping in HfO2. The ferroelectric properties of the modified HfO2 thin films yield high potential for various ferroelectric, piezoelectric, and pyroelectric applications. Furthermore, due to the extensive knowledge accumulated by various research groups regarding the HfO2 dielectric, an immediate relevance of ferroelectric hafnium oxide thin films is anticipated by the authors.
Arynes and Cyclohexyne in Natural Product Synthesis
Authors: Gampe Christian M. , Carreira Erick M.
Published: March 2012

This Minireview highlights recent advances in the field of aryne and cyclohexyne chemistry that have allowed the extraordinary reactivity of these entities to be harnessed during the course of natural product syntheses. The syntheses presented rely on the use of these reactive species in chemoselective transformations and follow unprecedented synthetic strategies that are inspiring for the practitioners of synthetic organic chemistry.
Effect of nanoclay type on dyeability of polyethylene terephthalate/clay nanocomposites
Authors: Parvinzadeh Gashti Mazeyar , Moradian Siamak
Published: March 2012

Polyethylene terephthalate (PET)‐based nanocomposites containing three differently modified clays were prepared by melt compounding. The influence of type of clay on disperseability, thermal, and dyeing properties of the resultant nanocomposite was investigated by various analytic techniques, namely, X‐ray diffraction, optical microscopy (OPM), differential scanning calorimetry, thermal gravimetric analysis, dynamical mechanical thermal analysis, contact angle measurement (CAM), reflectance spectroscopy, and light fastness. OPM images illustrated formation of large‐sized spherulites in pure PET, while only small‐sized crystals appeared in PET/clay nanocomposites. Decreased glass transition temperatures for all PET/clay nanocomposites indicate that the amorphous regions of such composites become mobile at lower temperatures than those in pure PET. CAMs on the resultant PET composites demonstrated that the wettability of such composites depends on hydrophilicity of the nanoclay particles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of 3,4′‐oxydianiline on the structures and properties of a novel aromatic polyimide foam
Authors: Li Yin , Liu Xiao‐Yan , Zhan Mao‐Sheng , Wang Kai
Published: March 2012

Aiming at the low volumetric shrinkage, a novel aromatic polyimide foam is successfully prepared from polymethane polyphenyl isocyanate (PAPI) and a poly(amic‐acid) precursor which has been synthesized from 3,4′‐oxydianiline (3,4′‐ODA) and pyromellitic dianhydride (PMDA). In this research, five polyimide foams, with different contents of 3,4′‐ODA, are comparatively studied including structural, thermal, mechanical, shrink, and degradation properties. The results indicate that the content of 3,4′‐ODA has minor influence on chemical structures, but significant influence on cell structures of the foams. With the increase of 3,4′‐ODA, the volumetric shrinkages, apparent densities and the compressive and flatwise tensile strengths of the materials decrease. The glass transition temperatures (Tg) decrease from 301°C to 279°C, and the 5% weight loss temperatures (T5%) increase from 323°C to 340°C. Through TG‐FTIR analysis, we can observe that the addition of 3,4′‐ODA has no influence on the pyrolysis mechanism of polyimide foams. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Influence of Mesterolone on Satellite Cell Distribution and Fiber Morphology within Maturing Chicken Pectoralis Muscle
Authors: Allouh Mohammed Z. , Aldirawi Mohammed H.
Published: March 2012

Mesterolone is a synthetic oral anabolic androgenic steroid used to treat hypogonadism. There are frequent reports of mesterolone abuse in human and equine sports to increase muscle mass and strength. However, limited information is available about how this drug exerts its effects on skeletal muscle. Satellite cells (SCs) are mononuclear myogenic stem cells that contribute to postnatal muscle growth and repair. As SC activation and subsequent differentiation to new myonuclei is a major event during muscle hypertrophy, this study investigated the influence of mesterolone on SC distribution within the pectoralis muscle of chickens. Specifically, this study tested the hypotheses that mesterolone induces avian skeletal muscle hypertrophy, and that mesterolone increases the number of SCs in avian skeletal muscle. Robust immunocytochemical techniques and morphometric analyses were used to calculate the numbers of SCs and myonuclei. Also, DNA concentration and Pax7 protein levels were measured to confirm immunocytochemical findings. Mesterolone significantly increased pectoralis mass and fiber size. All SC indices and number of myonuclei increased significantly by mesterolone administration. In addition, greater DNA concentration and Pax7 protein expression were found in mesterolone‐treated birds. This study indicates that mesterolone can induce avian skeletal muscle hypertrophy and that this is correlated with increased number of SCs. We suggest that SCs are key cellular intermediaries for mesterolone‐induced muscle hypertrophy. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.