bluuebunny/crossref_metadata_2025 huggingface dataset:
Elastic Core Concept in Shakedown Analysis
Authors: Porowski Janek , O’Donnell Tom
Published: July 2009

Use of an Elastic Core concept in finite element inelastic analysis of shakedown for components subjected to cyclic loading is described. The Elastic Core is defined as the portion of the wall which remains elastic during the entire history of cyclic loading. If it can be shown that the Elastic Core continues to exist in the wall of a component during consecutive cycles, there is no ratchet. It is shown how elastic-plastic cyclic analysis conducted only for a limited number of cycles can be used to confirm the presence of the Elastic Core. The Elastic Core concept was introduced to bound the accumulated strain for structures in elevated temperature service including plasticity and creep (1974, 1979). The resulting evaluation method is included in the ASME Code. The ASME Boiler and Pressure Vessel Code, Section III and Section VIII, Division 2 provide rules for the evaluation of plastic ratcheting in components subjected to cyclic loading. These evaluations use results of elastic analysis for components subjected to mechanical and thermal loading below the creep regime. Equations defining the onset of plastic ratchet in the Code are based on a simplified one-dimensional model including sustained membrane stress and cyclic thermal bending stress. Therefore, they only provide approximate results. The proposed use of finite element analysis extends the application of the Elastic Core for redundant structures of complex geometry and loading conditions. The results obtained herein also show the usefulness of the Code method in predicting the behavior of these structures.
Vibration Reduction of Structural-Acoustic Systems Using Synchronized Switch Damping Techniques
Authors: Ciminello Monica , Deu¨ Jean-Franc¸ois , Ohayon Roger , Ameduri Salvatore
Published: July 2009

In this paper we present numerical results concerning vibration reduction of structural-acoustic systems using the synchronized switch control technique. In order to develop a general procedure to model the coupled system (composed by the fluid domain, the structure and the piezoelectric elements), the idea is to use the performances of a standard commercial code such as Nastran. A symmetric reduced order model is derived from a general finite element description through the extraction of appropriate system matrices. For sake of brevity, we just recall that depending upon the choice of fluid field variables, non symmetric formulations are usually obtained (so-called displacement-pressure formulations), the symmetrization can be derived through appropriate choice of fluid field variables [1, 2]. A simple fluid-structure system for which an analytic solution exists will be used to verify the finite element results and to demonstrate the capabilities of the control procedure. Referring to experimental tests [3], the system consists of a straight air-filled tube with a square cross section. The tube is a rigid cavity with an elastic plate at one end and a piezoelectric patch bonded in its centre. Firstly, the conservative structural-acoustic problem is presented. The symmetric variational and finite element formulations are then described. The model is constructed using Nastran software and the finite element matrices are then extracted and assembled in Matlab. In a second step, the electro-mechanical coupling matrices are built using three-dimensional finite elements in order to take into account local moments of the piezoelectric wafers according to the equivalent thermal coefficient theory [4, 5]. Finally, the reduced electro-mechanical fluid-structure system, obtained through a modal projection, is integrated in time using a Newmark type algorithm. Numerical results are then presented showing the performance of the synchronized switch damping for vibro-acoustic applications in the low frequency domain (low modal density).
An Integrated Approach for Health Monitoring of Multistorey R.C. Frame Structures
Authors: Shanker Rama , Bhalla Suresh , Gupta Ashok
Published: July 2009

This paper describes an experimental study to extract the dynamic characteristics of a two-storey reinforced concrete (RC) frame structure using piezo-electric ceramic (PZT) patches. PZT patches were embedded in the structure at the time of construction. Basically two techniques were applied to monitor the health of structure, the global dynamic technique and the local electro-mechanical impedance (EMI) technique. Global dynamic technique, which is based on frequency changes, is effective in low frequency range only. Due this limitation, initial damage/hair crack can not be detected by the global dynamic technique. On the other hand, EMI technique acts at higher frequency range and is very sensitive to detect the initial damage/hair cracks. The lower natural frequencies of the frame structure were determined experimentally using global techniques. The two-storey R.C. frame was modeled using ANSYS 9.0 to determine the frequencies numerically. Experimental results were compared with numerical results, which were found to be agreeable. Initial cracks were detected by the EMI technique. Severity and location of damage can be also determined with the help of these parameters. Inputs were chosen from these parameters to train an artificial neural network (ANN) whose outputs were the severity and the location of damage. Thus, complete monitoring can be done by the combination of global vibration and EMI technique using PZT patches. This integrated approach can be used for damage/crack detection at very early stage. This approach is very sensitive and cost effective to predict the incipient damages in civil structures.
Design of Variable-Length Piezocomposite Transducer for Structural Health Monitoring
Authors: Salas Ken I. , Cesnik Carlos E. S.
Published: July 2009

A modally-selective, variable-length anisotropic piezocomposite transducer is designed for guided wave (GW) structural health monitoring applications. The transducer dimensions needed to maximize individual modes are selected based on 3-D elasticity models for GW excitation by finite dimensional transducers. This theory is used to determine these transducer dimensions as a function of the wave phase velocity, and normalized by the substrate thickness. The design and fabrication of the transducer are subsequently described, and a set of experimental tests is conducted in pristine isotropic structures to characterize the actuation and sensing performance of the device. It is shown that the transducer dimensions can be tailored to obtain specific symmetric to antisymmetric mode transmission ratios.
Damage Detection in Composites Using Vibration Signatures and Mode Shapes
Authors: Oruganti K. , Mehdizadeh M. , John S. , Herszberg I.
Published: July 2009

Composite materials are supplanting conventional metals in aerospace, automotive, civil and marine industries in modern times. However, despite these advantageous properties, they are prone to delamination or matrix cracking. Thus, necessitating the early detection of the crack or flaw before it initiates into a serious defect. An offline approach was commonly used where in the parts examined away from service/operation. This not only consumed a lot of time but risked damage to the part during operation and handling. A detailed understanding of the various proven methods and techniques and their applicability in the analysis of vibration signatures obtained from damaged structures under dynamic conditions is essential to develop a reliable Structural Health Monitoring System (SHMS). This paper includes Vibration based damage detection testing on Carbon/Epoxy composite beams. Such composites are commonly used in the aerospace and marine industry. This material type is gaining acceptance not only in the aerospace industry but also in the automotive and construction industries. The paper reports the processing of the vibration signatures from healthy and damaged composite beams upon excitation and analysis of the mode shapes acquired. The study comprises of testing carbon/epoxy composite beams with various embedded delaminations with a mechanical actuator and a scanning laser vibrometer (SLV) as a sensor for recording the frequency response and analysing the acquired signatures based on Displacement and Curvature Mode Shapes.
Dynamic Response of Tubular Dielectric Elastomer Sensors and Actuators
Authors: Son S. , Goulbourne N. C.
Published: July 2009

This paper presents experimental and numerical modeling results for the dynamic response of a tubular dielectric elastomer sensor and actuator for the first time. Dielectric elastomers (DE) are soft polymer based smart materials that can be potentially employed in applications such as artificial muscles (prosthetics), compliant limbs and graspers for robots and aircrafts or aquatic vehicles. In our previous work, the quasi-static response of tubular DE sensors was studied [1]. Here, a theoretical model is developed to predict the dynamic response of tubular DE transducers. To this end, inertia effects are included in our previous static model which yields a system of partial differential equations. The dynamic response of the tubular DE is obtained by numerically solving the simplified PDEs using a finite difference scheme. The capacitance change induced by the dynamic deformation of the tubular DE is also calculated by a simple electrostatic model. Several tubular DE transducer samples (VHB 4905 and silicone) were fabricated and an experimental setup was developed to investigate the dynamic response by measuring capacitance and radial deformation. In the sensing experiments, a sweep of dynamic pressure profiles (0∼5Hz) are applied It is observed that silicone transducers have a larger dynamic sensing range. In the actuation experiments, the deformation of the silicone actuator is monitored while a voltage signal (4.5kV) is applied from 0∼30Hz. The silicone actuator shows a good actuation response while high voltage is applied. The comparison between numerical and experimental results for the DE transducers shows an overall error of 3%.
Crack Detection in Shafts of Rotating Machinery Using Active Sensing With an External Excitation on a Bearing
Authors: Machorro-Lo´pez Jose´ M. , Adams Douglas E. , Go´mez-Mancilla Julio C.
Published: July 2009

Because several power plants have undergone burst shafts with catastrophic consequences, methods for detecting cracks in the shafts of rotating machinery are of great interest to the research community. Cracked shafts represent a very small percentage of the vibration issues in machinery (less than 2%) compared with other faults such as misalignment and mass imbalance, which are responsible for 85% of these issues. However, if a cracked shaft is not detected early enough, it can jeopardize the safety of operators and result in high costs for replacement. A method sensitive enough to detect cracks in the shafts of rotating machinery is investigated in this paper. It is shown that changes in the natural frequencies and/or mode shapes are not sensitive enough indicators to detect transverse cracks at the mid-span of shafts in rotating machinery. An exhaustive numerical analysis using a finite element model of a simple machine is conducted to consider many different measurements of the machinery vibratory responses that most clearly detect cracking. It is shown that external excitations applied on a bearing enhance the sensitivity of vibration measurements to cracking. Experimental tests are also used to validate several of the numerical simulation findings.
Experimental Detection and Quantitative Interrogation of Damage in a Jointed Composite Structure
Authors: Gentzen Vanessa , Choi Young-Tai , Purekar Ashish S. , Wereley Norman M.
Published: July 2009

The study addresses experimental detection and quantitative interrogation of damage in a jointed composite structure. To construct a cohesive structural health monitoring system for the jointed composite panel, the wave propagation method was used with smart piezoelectric transducers for excitation and sensing. The smart sensor system was configured using four piezo patches located at the four quadrants of the composite panel, and provided multiple actuation/sensing scenarios to capture time and frequency response signals for a variety of bolt damage configurations. Signal information was compressed into non-dimensional damage indices at each excitation configuration. The collected information was used in a pattern recognition algorithm. Based on pattern recognition, a damage discriminator was generated which indicated location and amount of damage information automatically. Using simulated bolt torque loss damage on a jointed composite structure, the damage detection performance of the damage discriminator was evaluated.
Stiffness Shaping for Zero Vibration Fluidic Flexible Matrix Composites
Authors: Lotfi-Gaskarimahalle Amir , Shan Ying , Li Suyi , Rahn Christopher D. , Bakis Charles E. , Wang K. W.
Published: July 2009

This paper studies semi-active vibration control using Fluidic Flexible Matrix Composites (F2MC) as variable stiffness structures. The apparent stiffness of F2MC tubes can be changed using a variable orifice valve. With fiber reinforcement, the volume inside the tube may change with external load. With an open valve, the liquid is free to move in or out of the tube, so the apparent stiffness will not changed. When the valve is closed, the high bulk modulus liquid is confined, which resists the volume change and causes the apparent stiffness of the tube to increase. The equations of motion of an F2MC-mass system is derived using a 3D elasticity model and the energy method. A reduced order model is then developed for fully-open or fully-closed valves. A Skyhook valve that cycles the valve between open and closed, asymptotically decays the vibration. A Zero Vibration (ZV) Stiffness Shaping technique is introduced to suppress the vibration in finite time. A sensitivity analysis of the ZV Stiffness Shaper studies the robustness to parameteric uncertainties.
Analytical Modeling for the Shape Control of an Adaptive Composite Satellite Dish
Authors: Yan Su , Ghasemi-Nejhad Mehrdad N.
Published: July 2009

A three-dimensional dynamic analysis of a satellite dish in spherical coordinate system is investigated. The method of separation of variables is employed to obtain the explicit 3D solution of the partial differential governing equation of the active composite satellite dish (ACSD). Then, the mode shape functions are expanded as a combination of periodic functions, associated Legendre functions, and spherical Bessel functions. The validation of the theoretical model is performed by comparing the developed analytical mode shapes with finite element method (FEM) mode shapes. Also, using the developed analytical model, the disturbance observer (DOB) controller is employed for the ACSD shape control. The numerical results show that, by employing the DOB controller, more accurate shape control of the satellite dish is achieved and less control energy is consumed, when piezoelectric actuator patches are placed on their optimal locations.
Structural Health Monitoring of Composite Plates Subjected to Impacts Using the Electromechanical Impedance Technique
Authors: Tsuruta Karina M. , Cunha Leandro R. , Rade Raquel S. L. , Rade Domingos A.
Published: July 2009

The aim of this paper is to evaluate the use of the Structural Health Monitoring (SHM) technique based on the concept of electromechanical impedance for the assessment of low-energy impact damage in laminated carbon-fiber composite plates. The experiments were carried-out by using an especially designed pendulum, and were planned in such a way to accommodate a range of test conditions, such as impact energy and dimension of the impacting piece. Also, it was investigated the influence of the frequency band in which the impedance functions are measured. Additionally, statistical metamodels were built aiming at establishing functional relations between the values of the damage metric and impact energy for single and multiple impacts. The obtained results demonstrate the capability of the monitoring method to identify various damage levels corresponding to different impact conditions.
Damage Detection in Thick Steel Beam Using Lamb Waves
Authors: Sun Kai , Meng Guang , Li Fucai , Ye Lin , Lu Ye
Published: July 2009

Different from the mostly concerned Lamb wave-based damage detection for thin plates, this paper presents a diagnosis procedure on thick steel beams with thickness of 34 mm. The diagnosis strategy and specimens were first described, and some parameters, such as the frequency and the number of cycles of the diagnostic waveform, were discussed. Based on finite element method (FEM) simulation, the experiment configuration was addressed, results from which show good similarity between the outcomes from the simulations and those from the experiments. Wavelet transform was further used to process the acquired Lamb wave signals for the purpose of damage detection and localization. Meanwhile, the velocity of the Lamb waves was calculated, illustrating that the fundamental anti-symmetric (A0) Lamb wave mode was excited in this case. The results demonstrate that Lamb waves can also be applied to some thick structures for the purpose of structural health monitoring.
Effects of Braid Angle on Pneumatic Artificial Muscle Actuator Performance
Authors: Gentry Michael F. , Wereley Norman M.
Published: July 2009

Pneumatic artificial muscles (PAMs) provide numerous advantages for use as actuators in a wide variety of mechanical systems. Our study focused on determining the effects of braid angle on the performance of PAMs. This paper discusses how we constructed a set of PAMs with varying braid angle, predicted their performance using analytical models, gathered empirical data characterizing the PAMs, and compared the analytical predictions with the experimental results. We constructed six PAMs of different braid angles between 38° and 73°. To predict PAM performance, we used an analysis based on the force equilibrium equations for a pressurized actuator. We first quantified the performance limits of each actuator in a series of static characterization tests. Then we subjected each PAM to cyclical displacement testing. Finally, a series of cyclical tests were performed with a pre-strain applied to the PAMs, to better approximate their typical use. Our results showed variation of braid angle causes significant differences in performance among the six PAMs tested; PAMs with larger braid angle generated higher blocked force and exhibited greater contraction. The empirical data matched the model predictions based on our estimates for the braid angle of a given PAM.
Enzyme-Mediated Self-Assembly of Highly Ordered Structures From Disordered Proteins
Authors: Athamneh Ahmad , Barone Justin
Published: July 2009

Trypsin hydrolysis of wheat gluten produced glutamine-rich short peptides with a tendency to self-assemble into supermolecular structures extrinsic to native wheat gluten. Fourier transform infrared and X-ray diffraction data suggested that the new structures formed resembled that of cross-β amyloid fibrils found in some insect silk and implicated in prion diseases. The superstructures were about 10 μm in diameter with clear right-handed helical configuration and appeared to be bundles of smaller fibrils of about 63 nm in diameter. Results demonstrate the potential for utilizing cheap protein sources and natural mechanisms of protein self-assembly to design advanced nanomaterials that can provide a wide range of structural and chemical functionality.
Design and Validation of Carbon Nanotube Thin Film Wireless Sensors for pH and Corrosion Monitoring
Authors: Loh Kenneth J. , Lynch Jerome P.
Published: July 2009

Corrosion damage in civil, aeronautical, and mechanical systems poses significant risks to users and occupants while simultaneously burdening owners with costly repairs and maintenance. Although many different sensing technologies are available to monitor corrosion processes, many cannot be easily implemented in field environments due to requiring expensive data acquisition systems and their destructive and intrusive measurement strategies. In this study, a novel layer-by-layer assembled carbon nanotube and poly(aniline)-based nanocomposite pH sensor is developed for monitoring corrosion of metallic and reinforced concrete structures. First, the electrochemical response of the proposed nanocomposite pH sensor is characterized using time-domain two-point resistance probing measurements to validate its resistance change to different pH buffer solutions (1 to 13). Frequency-domain electrical impedance spectroscopic studies and equivalent circuit analyses confirm changes in film resistance to pH. Upon sensor characterization, these nanocomposites are directly deposited onto printed circuit board coil antennas to realize a miniature passive wireless sensor capable of being embedded within structural materials. Preliminary wireless pH sensing results are presented to demonstrate that the wireless sensor’s bandwidth decreases at 3.9 kHz-pH−1 with increasing pH.
Design and Fabrication of a Bio-Inspired Flapping Flight Micro-Air Vehicle
Authors: Bunget Gheorghe , Seelecke Stefan , Place Thomas J.
Published: July 2009

The main objective of the BATMAV project is the development of a biologically-inspired Micro Aerial Vehicle (MAV) with flexible and foldable wings for flapping flight. While flapping flight in MAV has been previously studied and a number of models were realized they usually had unfoldable wings actuated with DC motors and mechanical transmission to provide the flapping motion, a system that brings the disadvantage of a heavy flight platform. This phase of the BATMAV project presents a flight platform that features bat-inspired wings with a number of flexible joints to allow mimicking the kinematics of the real mammalian flyer. The bat was chosen after an extensive analysis of the flight parameters of small birds, bats and large insects characterized by a superior maneuverability and wind gust rejection. Morphological and aerodynamic parameters were collected from existing literature and compared concluding that bat wing present a suitable platform that can be actuated efficiently using artificial muscles. Due to their wing camber variation, the bat species can operate effectively at a large rage of speeds and allow remarkably maneuverable and agile flight. Bat skeleton measurements were taken and modeled in SolidWorks to accurately reproduce bones and body via rapid prototyping machines. Much attention was paid specifically to achieving the comparable strength, elasticity, and range of motion of a naturally occurring bat. Therefore, a desktop model was designed, fabricated and assembled in order to study and optimize the effect of various flapping patterns on thrust and lift forces. As a whole, the BATMAV project consists of four major stages of development: the current phase — design and fabrication of the skeletal structure of the flight platform, selection and testing different materials for the design of a compliant bat-like membrane, analysis of the kinematics and kinetics of bat flight in order to design a biomechanical muscle system for actuation, and design of the electrical control architecture to coordinate the platform flight.
Reduced Mass-Weighted Proper Decomposition for Modal Analysis
Authors: Yadalam Venkata K. , Feeny B. F.
Published: July 2009

A method of modal analysis by proper orthogonal decomposition for large-order systems of arbitrary mass distribution is outlined. The method involves reduced-order modeling of the system mass distribution so that the discretized mass matrix dimension matches the number of sensed quantities, and hence the dimension of the response ensemble and correlation matrix. In this case, the linear interpolation of unsensed displacements is used to perform an effective lumped mass homogenization. The idea is applied to the modal identification of a mass-spring system and an exponential rod.
Ultrasonic Guided Wave Imaging Techniques in Structural Health Monitoring
Authors: Yan Fei , Rose Joseph L. , Royer Roger L.
Published: July 2009

Ultrasonic guided waves, due to theirs capability of interrogating a large structure from a single sensor position, has been proven as a promising tool for structural health monitoring (SHM). In this paper, we present two imaging approaches of utilizing guided wave leave-in-place sensors for early detection of defects in plate-like structures as well as for monitoring the defect growth. The first approach is based on a guided wave tomographic technique, in which the region surrounded by a sparse sensor array is monitored. The second one is a phased array approach, in which sensors are attached to a structure in a compact format to form an array. The region subjected to inspection and monitoring is the region outside the array. Both techniques have shown excellent capability of determining damage size, location, and severity.
Singular Value Decomposition Based Algorithm for Damage Detection in Composite Structures
Authors: Shane Conner , Jha Ratneshwar
Published: July 2009

This study presents a damage detection algorithm based on the proper orthogonal decomposition technique for health monitoring of composite structures. A finite element model of a carbon/epoxy composite plate is used to generate vibration data for healthy and damaged structures. Varying levels of stiffness reduction for the elements in the damaged zone of the structure simulate impact damage. Three damage locations (center of plate, fixed end, and free end) with three damage levels for each location are investigated. Different random excitation inputs are used to introduce variation in the loading conditions of the model. The results clearly show that damage presence, location, and severity can be detected using this algorithm.
On Superharmonic Resonances of Nonlinear Nonuniform Beams
Authors: Caruntu Dumitru I.
Published: July 2009

Superharmonic resonances of nonlinear forced bending vibrations of moderately large curvature of nonuniform cantilever beams of rectangular cross section and a sharp end are reported. Cantilevers of constant width and parabolic thickness variation are considered in this paper. Method of multiple scales is directly applied to the governing partial-differential equation of motion and boundary conditions. Two problems, zero- and first-order problem, result. Solving the zero-order problem, the linear modes are obtained in terms of hypergeometric functions by using the factorization method. The first-order problem provides the amplitude and phase evolution equation and consequently the superharmonic frequency response of the nonlinear system.
Energy Harvesting by Pyroelectric Effect Using PZT
Authors: Xie J. , Mane P. P. , Green C. W. , Mossi K. M. , Leang Kam K.
Published: July 2009

This paper considers energy harvesting using pyroelectric materials such as PZT-5A and thin-films. A simple model is used to predict the power generated based on the measured temperature of the material as a function of time. The measured and predicted results are presented and compared. In particular, the measured peak power density for a PZT-5A sample was 0.23 μWcm−2 for a maximum temperature rate of approximately 15 °Cs−1. The predicted peak power density under the same boundary conditions for thin-film lead scandium tantalate was over 125 μWcm−2. The power density is shown to be highly dependent upon the surface area and the pyroelectric coefficient, underlining the importance of maximizing these parameters.
Feature Reduction for Computationally Efficient Damage State Classification Using Binary Tree Support Vector Machines
Authors: Coelho Clyde , Chattopadhyay Aditi
Published: July 2009

This paper proposes a computationally efficient methodology for classifying damage in structural hotspots. Data collected from a sensor instrumented lug joint subjected to fatigue loading was preprocessed using a linear discriminant analysis (LDA) to extract features that are relevant for classification and reduce the dimensionality of the data. The data is then reduced in the feature space by analyzing the structure of the mapped clusters and removing the data points that do not affect the construction of interclass separating hyperplanes. The reduced data set is used to train a support vector machines (SVM) based classifier and the results of the classification problem are compared to those when the entire data set is used for training. To further improve the efficiency of the classification scheme, the SVM classifiers are arranged in a binary tree format to reduce the number of comparisons that are necessary. The experimental results show that the data reduction does not reduce the ability of the classifier to distinguish between classes while providing a nearly fourfold decrease in the amount of training data processed.
An Ultra-Lightweight Multi-Source Power Harvesting System for Insect Cyborg Sentinels
Authors: Reissman Timothy , Garcia Ephrahim
Published: July 2009

The overall purpose of this study was to analyze multi-source energy harvesters for creation of a rechargeable onboard power system, capable of supplying 5–50mW of intermittent power at a system mass of less than one gram, to be placed on a cyborg MAV (CMAV). To recharge the system, three sources of available ambient energy with respect to the application were explored, solar, thermal, and kinetic. Evaluations were performed based on magnitudes of available energy from each source, mass, dimension, and biocompatible constraints for each of the transducers, and specific power output of each energy harvester. Conclusions of this research show the magnitudes of the performance for photo-voltaic, thermoelectric, piezoelectric, and electromagnetic transducers weighing less than one gram. In addition, issues related to combining these multi-sourced energy harvesters into a collective power system are discussed.
SDH5
, a Gene Required for Flavination of Succinate Dehydrogenase, Is Mutated in Paraganglioma
Authors: Hao Huai-Xiang , Khalimonchuk Oleh , Schraders Margit , Dephoure Noah , Bayley Jean-Pierre , Kunst Henricus , Devilee Peter , Cremers Cor W. R. J. , Schiffman Joshua D. , Bentz Brandon G. , Gygi Steven P. , Winge Dennis R. , Kremer Hannie , Rutter Jared
Published: July 2009

Tapping the Mitochondrial Proteome

Mitochondria produce the energy that cells need to survive, function, and divide. A growing list of human disorders has been traced to defects in mitochondrial function. About 300 mammalian mitochondrial proteins are functionally uncharacterized, and

Hao
et al.

(p.
1139
, published online 23 July) reasoned that the most highly conserved proteins within this group might provide insights into human disease. A combination of bioinformatics, yeast genetics, biochemistry, and human genetics was used to show that a previously uncharacterized mitochondrial protein (Sdh5) is required for the activity of respiratory complex II. Inactivating mutations in the human gene encoding
SDH5
were found in individuals with hereditary paraganglioma, a rare neuroendocrine tumor. Thus, analysis of a mitochondrial protein in yeast has revealed a human tumor susceptibility gene.
The Cooking Ape
Catching Fire
How Cooking Made Us Human

by Richard Wrangham

Basic Books, New York, 2009. 315 pp. $26.95, C$33.95. ISBN 9780465013623.
Fire
The Spark That Ignited Human Evolution

by Frances D. Burton

University of New Mexico Press, Albuquerque, 2009. 245 pp. $34.95. ISBN 9780826346469.
Authors: Keller Andreas
Published: July 2009

In their books, Wrangham and Burton present two quite different perspectives on how learning to control fire may have played a crucial role in human evolution.
Evolutionary Photonics with a Twist
Authors: Vukusic Pete
Published: July 2009

The iridescent appearance of the hard forewings of scarab beetles can be caused by complex helical nanostructures.
Data Integrity Report Sends Journals Back to the Drawing Board
Authors: Kaiser Jocelyn
Published: July 2009

A National Academies panel released a report this week offering broad principles for dealing with data but calling on disciplines to work out the details themselves.
Comprehensive Test Ban: The Long Road
Authors: Clery Daniel
Published: July 2009

Science
gives a timeline of the steps that have been taken over the past half-century leading to the current effort for a comprehensive ban on nuclear weapons testing.
Deadly Flights
Authors: Curry Andrew
Published: July 2009

Massive wind turbines seem to be killing more and more migratory bats, prompting research into these neglected creatures and efforts to minimize the toll.
Toll-Like Receptor 3 Mediates Establishment of an Antiviral State against Hepatitis C Virus in Hepatoma Cells
Authors: Wang Nan , Liang Yuqiong , Devaraj Santhana , Wang Jie , Lemon Stanley M. , Li Kui
Published: July 2009

Toll-like receptor-3 (TLR3) senses double-stranded RNA, initiating signaling that activates NF-κB and interferon regulatory factor 3 (IRF-3), thereby inducing the synthesis of proinflammatory cytokines, type I interferons, and numerous interferon-stimulated genes (ISGs). This pathway has not been extensively investigated in human hepatocytes, and its role in sensing and protecting against hepatitis virus infections is uncertain. We show here that primary human hepatocytes express TLR3 and robustly upregulate ISGs upon poly(I·C) stimulation. We also show that TLR3 senses hepatitis C virus (HCV) infection when expressed in permissive hepatoma cells, acting independently of retinoic acid-inducible gene I and inducing IRF-3 activation and the synthesis of ISGs that restrict virus replication. In turn, HCV infection reduces the abundance of TRIF, an essential TLR3 adaptor, and impairs poly(I·C)-induced signaling. The induction and disruption of TLR3 signaling by HCV may be important factors in determining the outcome of infection and the ability of HCV to establish persistent infections.
Delirium in the elderly: a clinical review
Authors: Saxena S , Lawley D
Published: July 2009

Delirium is a common condition in the elderly, affecting up to 30% of all older patients admitted to hospital. There is a particularly high risk of delirium in surgical inpatients, especially following operations for hip fracture or vascular surgery, but also for patients in the intensive care unit. Patients with delirium have higher morbidity and mortality rates, higher re-admission rates, and a greater risk of long term institutionalisation care, thereby having a significant impact on both health and social care expenditure. Delirium frequently goes unrecognised by clinicians and is often inadequately managed. Recent evidence suggests that a better understanding and knowledge of delirium among health care professionals can lead to early detection, the reduction of modifiable risk factors, and better management of the condition in the acute phase. Many cases of delirium are potentially preventable, and primary and secondary care services should be taking active steps in order to do prevent this condition.
ARBITRARY l-WAVE BOUND STATE SOLUTIONS OF THE SCHRÖDINGER EQUATION WITH THE ECKART POTENTIAL
Authors: DIAO YONG-FENG , YI LIANG-ZHONG , CHEN TAO , JIA CHUN-SHENG
Published: July 2009

By using a modified approximation scheme to deal with the centrifugal term, we solve approximately the Schrödinger equation for the Eckart potential with the arbitrary angular momentum states. The bound state energy eigenvalues and the unnormalized radial wave functions are approximately obtained in a closed form by using the supersymmetric shape invariance approach and the function analysis method. The numerical experiments show that our analytical results are in better agreement with those obtained by using the numerical integration approach than the analytical results obtained by using the conventional approximation scheme to deal with the centrifugal term.
ELECTRON TRANSPORT IN STRONGLY CORRELATED NANOSTRUCTURES
Authors: AL-HASSANIEH K. A. , BÜSSER C. A. , MARTINS G. B.
Published: July 2009

We present a short review on electron transport in strongly correlated nanostructures, quantum dots in particular. We describe briefly the main correlation effects, namely the Coulomb blockade and Kondo effect, and introduce three widely used numerical techniques to study these effects. We then give a brief summary of some more elaborate set-ups where two or more effects compete, making the transport properties very interesting to study. In particular, we report the cases of multilevel quantum dots, carbon nanotube based quantum dots, and quantum dots coupled by RKKY interaction.
DISCOVERING FUZZY UNEXPECTED SEQUENCES WITH CONCEPT HIERARCHIES
Authors: LI DONG (HAOYUAN) , LAURENT ANNE , PONCELET PASCAL
Published: July 2009

Sequential pattern mining is the method that has received much attention in sequence data mining research and applications, however, a drawback is that it does not profit from prior knowledge of domains. In our previous work, we proposed a belief-driven method with fuzzy set theory for discovering the unexpected sequences that contradict existing knowledge of data, including occurrence constraints and semantic contradictions. In this paper, we present a new approach that discovers unexpected sequences with determining semantic contradictions by using concept hierarchies associated with the data. We evaluate the effectiveness of our approach with experiments on Web usage analysis.
REDUCTIONS OF NOISE AND UNCERTAINTY IN ANNUAL GLOBAL SURFACE TEMPERATURE ANOMALY DATA
Authors: HUANG NORDEN E. , WU ZHAOHUA , PINZÓN JORGE E. , PARKINSON CLAIRE L. , LONG STEVEN R. , BLANK KARIN , GLOERSEN PER , CHEN XIANYAO
Published: July 2009

Global climate variability is currently a topic of high scientific and public interest, with potential ramifications for the Earth's ecologic systems and policies governing world economy. Across the broad spectrum of global climate variability, the least well understood time scale is that of decade-to-century.1 The bases for investigating past changes across that period band are the records of annual mean Global Surface Temperature Anomaly (GSTA) time series, produced variously in many painstaking efforts.2–5 However, due to incipient instrument noise, the uneven distribution of sensors spatially and temporally, data gaps, land urbanization, and bias corrections to sea surface temperature, noise and uncertainty continue to exist in all data sets.1, 2, 6–8 Using the Empirical Mode Decomposition method as a filter, we can reduce this noise and uncertainty and produce a cleaner annual mean GSTA dataset. The noise in the climate dataset is thus reduced by one-third and the difference between the new and the commonly used, but unfiltered time series, ranges up to 0.1506°C, with a standard deviation up to 0.01974°C, and an overall mean difference of only 0.0001°C. Considering that the total increase of the global mean temperature over the last 150 years to be only around 0.6°C, we believe this difference of 0.1506°C is significant.
Calcium-dependent and calcium-independent inhibition of contraction by cGMP/cGKI in intestinal smooth muscle
Authors: Frei Eva , Huster Maria , Smital Petra , Schlossmann Jens , Hofmann Franz , Wegener Jörg W.
Published: July 2009

cGMP-dependent protein kinase I (cGKI) induces relaxation of smooth muscle via several pathways that include inhibition of intracellular Ca2+signaling and/or involve activation of myosin phosphatase. In the present study, we investigated these mechanisms comparatively in colon and jejunum longitudinal smooth muscle from mice. In simultaneous recordings from colon muscle, 8-bromo-cGMP (8-Br-cGMP) reduced both carbachol-induced tension and carbachol-induced increase in intracellular Ca2+concentration ([Ca2+]i). These effects of 8-Br-cGMP were absent in colon from mice carrying a mutated inositol-1,4,5 trisphosphate receptor I-associated G kinase substrate (IRAG) gene or lacking cGKI. However, in jejunum, 8-Br-cGMP reduced carbachol-induced tension but did not change corresponding [Ca2+]isignals. This setting was also observed in jejunum from mice carrying a mutated IRAG gene, whereas no response to 8-Br-cGMP was observed in jejunum from mice lacking cGKI. After inhibition of phosphatase activity by calyculin A, 8-Br-cGMP did not relax jejunum but still relaxed colon muscle. In Western blot analysis, 8-Br-cGMP reduced the signal for phosphorylated MYPT-1 in carbachol-stimulated jejunum but not in colon. These results suggest that cGMP/cGKI signaling differentially inhibits contraction in the muscles investigated: in jejunum, inhibition is performed without changing [Ca2+]iand is dependent on phosphatase activity, whereas in colon, inhibition is mediated by inhibition of [Ca2+]isignals.
Mechanisms underlying the antifibrotic properties of noninhibitory PAI-1 (PAI-1R) in experimental nephritis
Authors: Huang Yufeng , Border Wayne A. , Lawrence Daniel A. , Noble Nancy A.
Published: July 2009

Administration of a mutant, noninhibitory PAI-1 (PAI-1R), reduces disease in experimental glomerulonephritis. Here we investigated the importance of vitronectin (Vn) binding, PAI-1 stability and protease binding in this therapeutic effect using a panel of PAI-1 mutants differing in half-life, protease binding, and Vn binding. PAI-1R binds Vn normally but does not inhibit proteases. PAI-1AK has a complete defect in Vn binding but retains full inhibitory activity, with a short half-life similar to wild-type (wt)-PAI-1. Mutant 14-lb is identical to wt-PAI-1 but with a longer half-life. PAI-1K has defective Vn binding, inhibits proteases normally, and has a long half-life. In vitro wt-PAI-1 dramatically inhibited degradation of mesangial cell ECM while the AK mutant had much less effect. Mutants 14-1b and PAI-1K, like wt-PAI-1, inhibited matrix degradation but PAI-1R failed to reverse this inhibition although PAI-1R reversed the wt-PAI-1-induced inhibition of ECM degradation in a plasmin-, time-, and dose-dependent manner. Thus the ability of PAI-1 to inhibit ECM degradation is dependent both on its antiproteinase activity and on maintaining an active conformation achieved either by Vn binding or mutation to a stable form. Administration of these PAI-1 mutants to nephritic rats confirmed the in vitro data; only PAI-1R showed therapeutic effects. PAI-1K did not bind to nephritic kidney, indicating that Vn binding is essential to the therapeutic action of PAI-1R. The ability of PAI-1R to remain bound to Vn even in a high-protease environment is very likely the key to its therapeutic efficacy. Furthermore, because both PAI-1R and 14-1b bound to the nephritic kidney in the same pattern and differ only in their ability to bind proteases, lack of protease inhibition is also keyed to PAI-1R's therapeutic action.
Intravesical combination treatment with antisense oligonucleotides targeting heat shock protein-27 and HTI-286 as a novel strategy for high-grade bladder cancer
Authors: Matsui Yoshiyuki , Hadaschik Boris A. , Fazli Ladan , Andersen Raymond J. , Gleave Martin E. , So Alan I.
Published: July 2009

Clinical results of current intravesical chemotherapeutics are insufficient, and novel and safe intravesical options for high-risk bladder cancer are required to prevent both recurrence and progression. In this study, we show promising efficacy of intravesical combination treatment using antisense oligonucleotides targeting heat shock protein-27 (Hsp27; OGX427) with HTI-286, a synthetic analogue of the marine sponge product hemiasterlin. The expression of Hsp27 in bladder cancer was examined using tissue microarray analysis. Then, four bladder cancer cell lines were screened for combination effects of OGX427 with HTI-286, and the molecular mechanisms underlying the synergic effect were analyzed. Chemosensitivity against HTI-286 was also compared between mock-transfected T24 (T24 mock) cells and Hsp27-overexpressing T24 (T24 Hsp27) cells. Furthermore, in vivo data were obtained in a bioluminescent orthotopic murine model of high-grade disease. Hsp27 is expressed at higher levels in bladder cancers compared with normal bladder epithelium. OGX427 significantly enhanced cytotoxicity of HTI-286. Combination treatment induced Akt inactivation and Bcl-2 down-regulation. T24 Hsp27 cells were more resistant to HTI-286 than T24 mock cells and showed stronger Akt activation after HTI-286 treatment. The protective effect of Hsp27 against HTI-286 was suppressed by LY294002, a phosphatidylinositol 3-kinase inhibitor, indicating that Hsp27-Akt interactions are key mechanisms to enhance chemosensitivity via OGX427. Intravesical combination therapy effectively inhibited orthotopic tumor growth without toxic side effects. Our results suggest that OGX427 enhances cytotoxicity of HTI-286 through Akt inactivation and provide strong preclinical proof-of-principle for intravesical administration of OGX427 in combination with HTI-286 for high-grade bladder cancer. [Mol Cancer Ther 2009;8(8):2402–11]
Ficolins: Complement-Activating Lectins Involved in Innate Immunity
Authors: Matsushita Misao
Published: July 2009

Ficolins are a group of oligomeric lectins with subunits consisting of both collagen-like and fibrinogen-like domains. The majority of ficolins identified in vertebrates and invertebrates to date recognize N-acetylglucosamine (GlcNAc). X-ray crystallographic analysis of human ficolins has shown that the fibrinogen-like domain binds to the N-acetylated moiety. Ficolins in serum are associated with MBL-associated serine protease (MASP). The ficolin-MASP complex binds directly to carbohydrates present on the surface of a variety of Gram-positive and Gram-negative bacteria through ficolin. Binding of the complex initiates complement activation via the lectin pathway, leading to generation of opsonic fragments of complement components, such as C3b, and to lysis of the bacteria by the membrane attack complex. Thus, serum ficolins play an important role in innate immunity.
Development of a Streptococcus pneumoniae Keratitis Model in Mice
Authors: Moore III Quincy C. , McCormick Clare C. , Norcross Erin W. , Onwubiko Chinwendu , Sanders Melissa E. , Fratkin Jonathan , McDaniel Larry S. , O’Callaghan Richard J. , Marquart Mary E.
Published: July 2009

Background:Streptococcus pneumoniae is a common cause of bacterial keratitis, and models to examine the ocular pathogenesis of this bacterium would aid in efforts to treat pneumococcal keratitis. The aim of this study was to establish a murine model of pneumococcal keratitis. Methods: The corneas of A/J, BALB/c or C57BL/6 mice were scratched and topically infected with a clinical strain of S. pneumoniae. Slitlamp examination (SLE), enumeration of bacteria in the corneas and histology were performed. Results: Bacteria were recovered from the eyes of A/J mice on postinfection (PI) days 1 [1.96 ± 0.61 log10 colony-forming units (CFU)] and 3 (1.41 ± 0.71 log10 CFU). SLE scores were significantly higher in the infected A/J mice as compared to the BALB/c or C57BL/6 mice on PI day 3 (p < 0.0001) and steadily increased over time, reaching a maximal value of 3.00 ± 0.35 on PI day 10. Histopathology revealed stromal edema and the influx of polymorphonuclear leukocytes on PI days 7 and 10, and corneal disruption on PI day 7. Conclusions:S. pneumoniae keratitis was established in A/J mice, but not BALB/c or C57BL/6 mice.