bluuebunny/crossref_metadata_2025 huggingface dataset:
Ride Performance Analysis of Semiactive Suspension Systems Based on a Full-Car Model
Authors: Ahmadian Mehdi , Blanchard Emmanuel
Published: May 2009

This paper extends the results for active suspensions obtained by Chalasani in 1986, by evaluating the potential of semiactive suspensions for improving ride performance of passenger vehicles. Numerical simulations are performed on a seven-degree-of-freedom full vehicle model in order to confirm the general trends found for a quarter-car model, used by the authors in an earlier study. This full car model is used not only to study the heave, but also the pitch and roll motions of the vehicle for periodic and discrete road inputs. The behavior of a semi-actively suspended vehicle is evaluated using the hybrid control policy, and compared to the behavior of a passively-suspended vehicle. The results of this study obtained with the periodic inputs indicate that the motion of the quarter-car model is not only a good approximation of the heave motion of a full-vehicle model, but also of the pitch and roll motions since both are very similar to the heave motion. The results obtained with the discrete road input show that, for the example used in this study, the hybrid configuration clearly yields better results than the passive configuration when the objective is to minimize different deflections, angles, and accelerations at the same time.
Metallic Front Beam Design
Authors: Cuartero Jesu´s , Miravete Antonio , Castejo´n Luis , Carrera Marco
Published: May 2009

In this paper, new advances in simulation of car frontal crash structure are presented. Experimental results have been used to calibrate constitutive material models and simulation procedures to obtain more accurate representation of material behavior under crash loading. These advanced computational techniques are then applied to the crash simulations of components. The front longitudinal beam studied in this paper is analyzed for frontal crash. Qualitative results on specific energy absorption, as well as the absolute energy absorbed by the structure, are especially relevant. Three designs are then proposed as potential solutions for the front side rail design. Through simulation of their impact into a wall the designs are compared on the basis of crush force and specific energy absorption and a preferred design is chosen.
A Novel Synthesis Design Approach for Continuous, Inhomogeneous Structures
Authors: Yogev Or , Antonsson Erik K.
Published: May 2009

This paper presents a novel approach for the design synthesis of continuous inhomogeneous structures. The objective of this research is to mimic biological principles of growth and evolution in order to explore a set of novel design configurations identified by high complexity both in topology and mechanical properties. The ability to synthesize novel structures is explored from an engineering point view, where the use of inhomogeneous properties can increase the ability of a structure to support external loads and minimize weight. Based on the observation that biological structures are inhomogeneous, in the sense that different cells have different properties, an artificial environment has been created which models the biological growth procedure with cells that serve as building blocks of the structure. Cell differentiation is expressed only in the sense of mechanical properties. Each cell contains an identical artificial DNA sequence which is executed during the growth procedure and stops once the structure meets desired engineering requirements, such as supporting loads. The DNA contains sets of rules which are encoded as a gene string. A relatively simple DNA sequence can give rise to complex inhomogeneous structures; small changes in the rules can lead to a significantly different structures with different properties. The representation of these rules is ideally suited for evolution, which will be applied in the future to evolve rule-sets that grow and develop high-performance inhomogeneous structures.
Coupling Effects and Sensitivity Analysis for Graycale System Reliability
Authors: Honda Tomonori , Antonsson Erik K.
Published: May 2009

Understanding of the risk and reliability of systems can be enhanced by modeling the grayscale degradation of the performance of components and determining the grayscale impact on the system performance. Rather than producing an estimate of the probability of the system being in either the working or the failed state, as more traditional risk and reliability modeling does, this approach produces estimates of the probability of the system being in any of a continuous range of states between fully working and completely failed. In this paper, earlier work is extended by exploring the cause of major differences between this new approach and traditional reliability analysis, as well as by developing sensitivity analysis for grayscale reliability. Because the coupling effect can cause significant differences between this approach and the traditional approach, the coupling effect of component degradation is explored through the examples of coupled and decoupled mass-spring-damper systems. Also, a new sensitivity measure for grayscale reliability is developed to determine how designers can trade changes in reliability with other design criteria such as cost.
Non-Dimensional Analysis of the Performance of Semiactive Vehicle Suspensions
Authors: Ahmadian Mehdi , Blanchard Emmanuel
Published: May 2009

An analytical study that evaluates the response characteristics of a two-degree-of freedom quarter-car model using passive and semi-active dampers is provided as an extension to the results published by Chalasani for active suspensions. The behavior of a semi-actively suspended vehicle is evaluated using the hybrid control policy, and compared to the behavior of a passively suspended vehicle. The relationship between vibration isolation, suspension deflection, and road-holding is studied for the quarter-car model. Three performance indices are used as a measure of vibration isolation (which can be seen as a comfort index), suspension travel requirements, and road-holding quality. These indices are based on the mean square responses to a white noise velocity input for three motion variables: the vertical acceleration of the sprung mass, the deflection of the suspension, and the deflection of the tire, respectively. The results of this study indicate that the hybrid control policy yields better comfort than a passive suspension, without reducing the road-holding quality or increasing the suspension displacement for typical passenger cars.
Empirically-Derived Principles for Designing Products With Flexibility for Future Evolution
Authors: Keese Darren A. , Tilstra Andrew H. , Seepersad Carolyn C. , Wood Kristin L.
Published: May 2009

Product designers seek to create products that are not only robust for the current marketplace but also can be redesigned quickly and inexpensively for future changes that may be unanticipated. The capability of a design to be quickly and economically redesigned into a subsequent product offering is defined as its flexibility for future evolution. Tools are needed for innovating and evaluating products that are flexible for future evolution. In this paper, a comprehensive set of design guidelines is created for product flexibility by merging the results of two research studies—a directed patent study of notably flexible products and an empirical product study of consumer products analyzed with a product flexibility metric. Via comparison of the results of these two studies, the product flexibility guidelines derived from each study are merged, cross-validated, and revised for clarity. They are organized in categories that describe how and under what circumstances they increase flexibility for future evolution. Examples are included to illustrate each guideline. The guidelines are also applied to an example application—the design of a new guitar string changer.
Study of Argumentative Negotiation in Collaborative Design
Authors: Jin Yan , Geslin Mathieu
Published: May 2009

Engineering of complex systems often involves teamwork. The team members must work together to identify requirements, explore design spaces, generate design alternatives, and make both interactive and joint design decisions. Due to the latency of information and the disciplinary differences, it is often a difficult process for the team members to reach agreements when needed. Negotiation has been studied as a method for facilitating information exchange, mutual understanding, and joint decision-making. In our previous work, we introduced an argumentation-based negotiation framework to support collaborative design. In this paper, we present an experiment study that was conducted to assess the impact of this negotiation support approach on the process and the outcome of collaborative design. The results of the experiment have shown both the positive effects and limitations of the approach.
Blind Estimation of General Tip Shape in Atomic Force Microscopy
Authors: Tian Fenglei , Qian Xiaoping
Published: May 2009

The use of a flared tip and bi-directional servo control in some recent atomic force microscopes (AFM) has made it possible for these advanced AFMs to image structures of general shapes with undercuts and reentrant surfaces. Since AFM images are distorted representation of sample surfaces due to the dilation (a.k.a. convolution) produced by the finite size of the probe, it is necessary to obtain the tip shape in order to correct such tip distortion. This paper presents an approach that can for the first time estimate general three-dimensional tip shape from its scanned image in these AFMs. It extends one existing blind tip estimation method to the dexel representation, a computer representation that can represent general 3D shapes. As such, it can estimate general tip shapes, including undercuts or reentrant features.
Understanding the Use of Language Stimuli in Concept Generation
Authors: Chiu I. , Shu L. H.
Published: May 2009

Natural language, which is closely linked to thought and reasoning, has been recognized as important to the design process. However, there is little work specifically on understanding the use of language as design stimuli. This paper presents the results of an experiment where verbal protocols were used to elicit information on how designers used semantic stimuli presented as words related to the problem during concept generation. We examined stimulus use at the word level with respect to part-of-speech classes, e.g., verbs, nouns and noun modifiers, and also how stimuli syntactically relate to other words and phrases that represent ideas produced by the participant. While all stimuli were provided in verb form, we found that participants often used stimuli in noun form, but that more new ideas were introduced while using stimuli as verbs and noun modifiers. Frequent use of stimuli in noun form appears to confirm that people tend to think in terms of objects. However, noun use of stimuli introduced fewer new ideas and therefore contributed less to concept formation in our study. This work highlights a possible gap between how people may tend to think, e.g., in terms of nouns, and how new ideas may be more frequently introduced e.g., through verbs and noun modifiers. Addressing this gap may enable development of a language-based concept generation support system to encourage innovative and creative solutions for engineering problems.
Design of a Compliant Micro-Clasp Mechanism for Micromanipulation Tasks
Authors: Krishnan Sandeep , Saggere Laxman
Published: May 2009

This paper introduces the concept of a novel compliant micromanipulator that is capable of manipulating irregularly shaped micro-scale objects by positively clasping the object. The controlled clasp capability of the micromanipulator can be useful to accomplish the manipulation of a wide range of micro-scale objects and biological specimens, especially those with irregular shapes and/or floating in a liquid medium where traditional tweezers or grippers are cumbersome or unsuitable. The monolithic structure of the micromanipulator comprises of two distinct parts: a body and a clasp. The body has a topology that magnifies a single rectilinear input actuation into two larger displacements at the input points to the clasp mechanism. The clasp mechanism comprises of rigid links connected by rotary joints in the form of low-resistance serpentine flexures. The mechanism “clasps” the target object by enveloping the object with a continuous mechanical boundary that eventually closes inwards and “locks” the object within the boundary. The paper presents a systematic design of the compliant micromanipulator and the analytical model governing the behavior of the clasp using topology optimization techniques and energy methods.
Effects of Coupler Specifications and Operational Conditions on the Longitudinal Freight Train Dynamics
Authors: Ansari Masoud , Younesian Davood , Esmailzadeh Ebrahim
Published: May 2009

The longitudinal dynamics of railway vehicles is studied in this paper. The model is a time domain and nonlinear one. Model includes a train-consist containing one locomotive, nine wagons and nine automatic couplers between them. The effects of different parameters, (such as stiffness and damping of automatic couplers, train speed and train acceleration during both accelerating and braking process) on the longitudinal train dynamics are investigated in a parametric study. It is found that increase of the train operational speed has no effect on the maximum tractive forces while it results in increasing the maximum pressing forces as well as the RMS (Root mean square) value of the coupler forces. Higher acceleration during accelerating leads to higher maximum tractive and pressings forces and also higher RMS value of the coupler forces. Although increase of acceleration during braking results in higher pressing coupler forces, but it has no effect on the maximum tractive force.
Effects of the Load Distribution Patterns on the Longitudinal Freight Train Dynamics
Authors: Ansari Masoud , Younesian Davood , Esmailzadeh Ebrahim
Published: May 2009

A comprehensive parametric study is carried out on the longitudinal dynamics of a freight train having different loading patterns. A nonlinear time domain model, with one locomotive and nine wagons, is considered. In another simulation the train model has two locomotives and eight wagons, and in both models, every two cars are connected to each other through an automatic coupler. The effects of different load distribution patterns on the coupler forces for the cases of ascending, descending, constant, ascending-descending and descending-ascending are investigated through a parametric sensitivity study. In order to investigate how an empty wagon and its position in a train-consist model may affect the overall longitudinal dynamic behavior of freight trains a second computer simulation model has been developed. Moreover, the best possible position for the second locomotive with the objective of reaching to the lower longitudinal forces, in the case that an additional locomotive is included will be discussed. Finally, an investigation is carried out to determine the kind of couplers with their relevant specifications that must be installed in different positions of a train-consist in order to improve the longitudinal train dynamic behavior.
Towards an Interactive Assessment Framework for Engineering Design Learning
Authors: Rose´ Carolyn P. , Gweon Gahgene , Arguello Jamie , Finger Susan , Smailagic Asim , Siewiorek Daniel P.
Published: May 2009

In this paper we explore the use of text processing technology for on-line assessment in an engineering design project class. We present results from a 5-week classroom study in a capstone engineering design course in which we explore the potential benefits of such technology for student learning in this context. Furthermore, we present results from ongoing work assessing student productivity based on features extracted from their conversational behavior in the course discussion board. While we found that typical shallow productivity measures such as number of posts, length of posts, or number of files committed have no correlation with an instructor assigned grade, we can achieve a substantial improvement using simple linguistic patterns extracted from on-line conversational behavior.
Affordances in Interior Design: A Case Study of Affordances in Interior Design of Conference Room Using Enhanced Function and Task Interaction
Authors: Kim Y. S. , Kim M. K. , Lee S. W. , Lee C. S. , Lee C. H. , Lim J. S.
Published: May 2009

Interior design of space is somewhat different from product design in view of followings: the space should afford the multiple users at the same time and afford appropriate interactions with human and objects which exist inside the space. This paper presents a case study of interior design of a conference room based on affordance concept. We analyzed all of users’ tasks in a conference room based on the human activities that are divided into human-object and human-human interactions. Function decomposition of an every object in conference room was conducted. The concept of a high-level function is used such as “configure the space” to satisfy the given condition of the number of humans, the types of conference, and so forth. The Function-Task Interaction (FTI) method was enhanced to analyze the interactions between functions and user tasks. Many low-level affordances were extracted, and high-level affordances such as enter/exitability, prepare-ability, present-ability, discuss-ability and conclude-ability were also extracted by grouping low-level affordances in the enhanced FTI matrix. In addition, the benchmarking simulation was conducted for several existing conference rooms and the results confirmed that the extracted affordances can be used for checklist and also for good guidance on interior design process.
Tolerance Induced Performance Variation of a High-Resolution Compliant Micro Stage
Authors: Tsai Jhy-Cherng , Hsiao Mandy , Chen Jau-Liang
Published: May 2009

Micro stage employs compliant structure is crucial for precision machinery as it can achieve nano-scale resolution fine displacement by deformation. This paper investigates the variations of stiffness and natural frequency due to dimensional tolerances of such a compliant micro stage that is suspended by four leaf springs and rotates with respect to hinges. Performances of the stage are evaluated by finite element method for various dimensions to investigate the effects of dimensions. A series of sensitivity analyses are also performed to investigate how tolerances affect the performance of the stage. It shows that the stiffness and natural frequency of the stage are strongly affected by the dimensions of leaf springs and the hinges. That is, tolerances of these dimensions are crucial and must be well designed and strictly controlled. It further shows that performance variation due to tolerances are nonlinear but can be properly designed with this approach.
Piezoelectric Microvalve for Precise Control of Gas Flow at High Pressure
Authors: Fazal Imran , Elwenspoek M. C.
Published: May 2009

We present a normally open piezoelectric actuated micro valve, based on the novel concept of micro and fine machining technology. This new design allows a wide controllable range for high flow at a high pressure difference between inlet and outlet. This promising combination of micro and fine machining (piezoelectric actuator) provides the opportunity to take the steps that control the flow precisely. The use of piezoelectric actuator provides the opportunity of continuous control of gas flow at any stage during entire valve operation. In our previous design, larger steps caused by the friction between screw threads, limits the controllability [1]. Additionally the power consumption is low as piezoactuator needs power only to take steps to control the flow of gas.
Analyzing Design Change Impacts in Modular Products With Analytic Network Process
Authors: Lee Hakyeon , Seol Hyeonju , Sung Nakhwan , Hong Yoo Suk , Park Yongtae
Published: May 2009

Since parts and systems are closely linked to each other in complex engineering products, a change in a single part or system causes changes in other parts or system, which in turn propagates further. This study aims to propose a novel approach to analysis of design change impacts in modular products with consideration of change propagation. The proposed approach measures the relative change impact (RCI) of each part or module on the whole product using analytic network process (ANP). A case study on the automobile system is presented to illustrate the proposed approach. The practical use of RCI is also discussed.
Eco-Architecture Analysis as a Method of End-of-Life Decision Making for Sustainable Product Design
Authors: Kwak Min Jung , Hong Yoo Suk , Cho Nam Wook
Published: May 2009

In recent years, sustainable product design has become a great concern to product manufacturers. An effective way to enhance the product sustainability is to design products that are easy to disassemble and recycle. An EOL strategy is concerned with how to disassemble a product and what to do with each of the resulting disassembled parts. A sound understanding of the EOL strategy from the early design stage could improve the ease of disassembly and recycling in an efficient and effective manner. We introduce a novel concept of eco-architecture which represents a scheme by which the physical components are allocated to EOL modules. An EOL module is a physical chunk of connected components or a feasible subassembly which can be simultaneously processed by the same EOL option without further disassembly. In this paper, a method for analyzing and optimizing the eco-architecture of a product in the architecture design stage is proposed. Using mathematical programming, it produces an optimal eco-architecture based on the estimation of the economic values and costs for possible EOL modules under the given environmental regulations.
Novel Highly Tunable MEMS Capacitors With Flexible Structure and Linear C-V Response
Authors: Shavezipur Mohammad , Hashemi Seyed Mohammad , Khajepour Amir
Published: May 2009

MEMS parallel-plate tunable capacitors are widely used in different areas such as tunable filters, resonators and communications (RF) systems for their simple structures, high Q-factors and small sizes. However, these capacitors have relatively low tuning range (50%) and are subjected to highly sensitive and nonlinear capacitance-voltage (C-V) responses. In this paper novel designs are developed which have C-V responses with high linearity and tunability and low sensitivity. The designs use the flexibility of the moving plates. The plate is segmented to provide a controllable flexibility. Segments are connected together at end nodes by torsional springs. Under each node there is a step which limits the vertical movement of that node. An optimization program finds the best set of step heights that provides the highest linearity. Two numerical examples of three-segmented- and six-segmented-plate capacitors verify that the segmentation of moving plate can considerably improve the linearity without decreasing the conventional tunability. A two-segmented-plate capacitor is then designed for standard processes which cannot fabricate steps of different heights. The new design uses a flexible step (spring) under middle node. The simulation of a capacitor with flexible middle step, designed for PolyMUMPs process, demonstrates a C-V response with high tunability and linearity and low sensitivity.
Calculation Methodology of Out of Plane Bending of Mooring Chains
Authors: ter Brake E. , van der Cammen J. , Uittenbogaard R.
Published: May 2009

Recently, the phenomenon of out-of-plane bending (OPB) fatigue of mooring chain links emerged as an important parameter in the fatigue assessment of mooring lines. Vessel motions induce a bending moment at the top chain of a mooring line. This bending moment induces alternating local stresses in the link and thus contributes to fatigue damage of those links. High pretension mooring systems are particularly sensitive to this phenomenon, since a small vessel motion combined with a high tension results in a relatively large bending moment in the upper mooring chain links. In mooring systems with high pre-tensions, this damage is of much greater magnitude than the fatigue damage induced by tension-tension loading only. An extensive study has been executed to investigate the fatigue life of mooring chain in deep water systems. This paper presents the calculation procedure to include the effects of local chain bending in the overall mooring line fatigue analysis. It was concluded that despite the complexity of the OPB issue, it is a phenomenon that can be incorporated in the mooring analyses by means of numerical procedures. The developed method is based on extensive Finite Element Method (FEM) analyses of chain links. Models of multiple chain links have been used that take into account the plastic-elastic properties of the material and contact friction between chain links. The FE models are used to derive empirical relations, between load angles, interlink angles, bending moments and stresses. These calculations were made for different combinations of line tension, interlink friction and chain size. The results were stored in a database to gain insight in the out-of-plane bending phenomenon. This database provides empirical formulas to lead to the local stress in different points on a chain link. These empirical formulas are used to translate floater (vessel or buoy) motions into local stress variations and fatigue damages in chain links. The long-term motion behaviour of the floater is known, the long term tension and bending stress ranges can be obtained and thus a fatigue damage of the chain links can be calculated.
Study a on Fuzzy MR Damper Vibration Control Strategy for Offshore Platforms
Authors: Ji Chunyan , Yin Qun
Published: May 2009

In order to reduce the dynamic responses of offshore platform effectively, fuzzy magnetorheological controller is adopted to control the offshore platform in this paper. Taking the error of offshore platform displacement responses and error variety as inputs, and the optimal control force as output, the optimal fuzzy controller is designed. Considering the limits for output force, semi-active control strategy is used to revise the output control force, which approximates to the optimal active control force calculated by the fuzzy control strategy. Finally a numerical example of offshore platform is used in this paper. The simulation results show that vibration of offshore platforms by using fuzzy control method is reduced effectively. In addition, the influence of uncertainties of external loads parameters and structural damping on control effect is analyzed in detail. The results indicate that the proposed method has good fuzziness on uncertainties of structural damping, while it has some weaker fuzziness on uncertainties of external loads parameters than on uncertainties of structural damping.
Estimating Distributions for Extreme Response of a Catenary Riser
Authors: Passano Elizabeth , Larsen Carl M.
Published: May 2009

The paper deals with the challenge of predicting the extreme response of catenary risers, a topic of both industry and academic interest. Large heave motions introduced at the upper end of a catenary riser can lead to compression and large bending moments in the region immediately above the touch down area. In the worst case, dynamic beam buckling may occur. Results from long nonlinear stochastic simulations of many seastates with varying environmental and operating conditions may be combined to describe the long-term response statistics of a nonlinear structure such as a catenary riser (So̸dahl, 1991). However, this theoretically straight-forward approach is very demanding computationally and ways to limit the extent of nonlinear stochastic simulations are therefore sought. Previous work by the authors (Passano and Larsen 2006) focussed on understanding the riser behaviour in extreme, low-tension response and on establishing suitable strategies for concentrating the nonlinear simulations to where they are most useful. The research presented in this paper is a continuation of this work. The clear trends found between the prescribed axial velocity at the upper end and response quantities in the touch down area (TDA) are used to estimate individual response values and complete samples of response minima / maxima. A method for estimating the underlying response distributions is also presented.
Safety and Environmental Challenges in Developing a Closed-Circuit LNG Regasification System for Offshore Natural Gas Export
Authors: Chang Daejun , Lee Donghun , Jeong Samheon , Chang Kwangpil
Published: May 2009

This study examined the safety and environmental issues encountered in the course of development of a closed-circuit LNG regasification system to be installed on offshore LNG terminals or regasification shuttles. Restriction on sea water usage as the heating medium intrinsically determined that the developed system should be based on a closed circuit assisted by steam-generating boilers. Care were taken in establishing the operation and control philosophy, not to generate any residual steam that needed inevitably to be condensed with sea water or to be vented to the atmosphere. One of the most critical hazards was the huge amount of blowdown gas in case of emergency shutdown. It was found that the discharge through a vent mast still left a considerable risk due to the gas dispersion around the facility. Instead, a restricted blowdown to the LNG containment system or a combustion unit resulted in a less risk with a prolonged duration. Rigorous studies were performed to quantify the risks and to anticipate the system behavior. The leak and fire risk analysis indicated that the system had significantly low frequency of fire and explosion compared with usual offshore facilities. However, any guidelines were not available to assess the risk quantitatively. The process dynamic simulation suggested how the system should be shut down. This study showed that several critical challenges were solved successfully and the risk level of the closed-circuit regasification system was acceptable.
Antigenic and Genetic Characteristics of Swine-Origin 2009 A(H1N1) Influenza Viruses Circulating in Humans
Authors: Garten Rebecca J. , Davis C. Todd , Russell Colin A. , Shu Bo , Lindstrom Stephen , Balish Amanda , Sessions Wendy M. , Xu Xiyan , Skepner Eugene , Deyde Varough , Okomo-Adhiambo Margaret , Gubareva Larisa , Barnes John , Smith Catherine B. , Emery Shannon L. , Hillman Michael J. , Rivailler Pierre , Smagala James , de Graaf Miranda , Burke David F. , Fouchier Ron A. M. , Pappas Claudia , Alpuche-Aranda Celia M. , López-Gatell Hugo , Olivera Hiram , López Irma , Myers Christopher A. , Faix Dennis , Blair Patrick J. , Yu Cindy , Keene Kimberly M. , Dotson P. David , Boxrud David , Sambol Anthony R. , Abid Syed H. , St. George Kirsten , Bannerman Tammy , Moore Amanda L. , Stringer David J. , Blevins Patricia , Demmler-Harrison Gail J. , Ginsberg Michele , Kriner Paula , Waterman Steve , Smole Sandra , Guevara Hugo F. , Belongia Edward A. , Clark Patricia A. , Beatrice Sara T. , Donis Ruben , Katz Jacqueline , Finelli Lyn , Bridges Carolyn B. , Shaw Michael , Jernigan Daniel B. , Uyeki Timothy M. , Smith Derek J. , Klimov Alexander I. , Cox Nancy J.
Published: May 2009

Generation of Swine Flu

As the newly emerged influenza virus starts its journey to infect the world's human population, the genetic secrets of the 2009 outbreak of swine influenza A(H1N1) are being revealed. In extensive phylogenetic analyses,

Garten
et al.

(p.
197
, published online 22 May) confirm that of the eight elements of the virus, the basic components encoded by the hemagglutinin, nucleoprotein, and nonstructural genes originated in birds and transferred to pigs in 1918. Subsequently, these formed a triple reassortant with the RNA polymerase PB1 that transferred from birds in 1968 to humans and then to pigs in 1998, coupled with RNA polymerases PA and PB2 that transferred from birds to pigs in 1998. The neuraminidase and matrix protein genes that complete the virus came from birds and entered pigs in 1979. The analysis offers insights into drug susceptibility and virulence, as well as raising the possibility of hitherto unknown factors determining host specificity. A significant question is, what is the potential for the H1 component of the current seasonal flu vaccine to act as a booster? Apart from the need for ongoing sequencing to monitor for the emergence of new reassortants, future pig populations need to be closely monitored for emerging influenza viruses.
Efficient Degradation of Lignocellulosic Plant Biomass, without Pretreatment, by the Thermophilic Anaerobe “
Anaerocellum thermophilum
” DSM 6725
Authors: Yang Sung-Jae , Kataeva Irina , Hamilton-Brehm Scott D. , Engle Nancy L. , Tschaplinski Timothy J. , Doeppke Crissa , Davis Mark , Westpheling Janet , Adams Michael W. W.
Published: May 2009

Very few cultivated microorganisms can degrade lignocellulosic biomass without chemical pretreatment. We show here that “
Anaerocellum thermophilum
” DSM 6725, an anaerobic bacterium that grows optimally at 75°C, efficiently utilizes various types of untreated plant biomass, as well as crystalline cellulose and xylan. These include hardwoods such as poplar, low-lignin grasses such as napier and Bermuda grasses, and high-lignin grasses such as switchgrass. The organism did not utilize only the soluble fraction of the untreated biomass, since insoluble plant biomass (as well as cellulose and xylan) obtained after washing at 75°C for 18 h also served as a growth substrate. The predominant end products from all growth substrates were hydrogen, acetate, and lactate. Glucose and cellobiose (on crystalline cellulose) and xylose and xylobiose (on xylan) also accumulated in the growth media during growth on the defined substrates but not during growth on the plant biomass.
A. thermophilum
DSM 6725 grew well on first- and second-spent biomass derived from poplar and switchgrass, where spent biomass is defined as the insoluble growth substrate recovered after the organism has reached late stationary phase. No evidence was found for the direct attachment of
A. thermophilum
DSM 6725 to the plant biomass. This organism differs from the closely related strain
A. thermophilum
Z-1320 in its ability to grow on xylose and pectin.
Caldicellulosiruptor saccharolyticus
DSM 8903 (optimum growth temperature, 70°C), a close relative of
A. thermophilum
DSM 6725, grew well on switchgrass but not on poplar, indicating a significant difference in the biomass-degrading abilities of these two otherwise very similar organisms.
Quantitative Real-Time PCR Assay for QPX (Thraustochytriidae), a Parasite of the Hard Clam (
Mercenaria mercenaria
)
Authors: Liu Qianqian , Allam Bassem , Collier Jackie L.
Published: May 2009

We developed a real-time quantitative PCR (qPCR) assay targeting the rRNA internal transcribed spacer region of the hard clam pathogen QPX. The qPCR assay was more sensitive than was histology in detecting clams with light QPX infections. QPX was detected in 4 of 43 sediment samples but in none of 40 seawater samples.
Syntrophic Degradation of Cadaverine by a Defined Methanogenic Coculture
Authors: Roeder Julia , Schink Bernhard
Published: May 2009

A novel, strictly anaerobic, cadaverine-oxidizing, defined coculture was isolated from an anoxic freshwater sediment sample. The coculture oxidized cadaverine (1,5-diaminopentane) with sulfate as the electron acceptor. The sulfate-reducing partner could be replaced by a hydrogenotrophic methanogenic partner. The defined coculture fermented cadaverine to acetate, butyrate, and glutarate plus sulfide or methane. The key enzymes involved in cadaverine degradation were identified in cell extracts. A pathway of cadaverine fermentation via 5-aminovaleraldehyde and crotonyl-coenzyme A with subsequent dismutation to acetate and butyrate is suggested. Comparative 16S rRNA gene analysis indicated that the fermenting part of the coculture belongs to the subphylum
Firmicutes
but that this part is distant from any described genus. The closest known relative was
Clostridium aminobutyricum
, with 95% similarity.
Construction and Characterization of Three Lactate Dehydrogenase-NegativeEnterococcus faecalisV583 Mutants
Authors: Jönsson Maria , Saleihan Zhian , Nes Ingolf F. , Holo Helge
Published: May 2009

The roles of the twoldhgenes ofEnterococcus faecaliswere studied using knockout mutants. Deletion ofldh-1causes a metabolic shift from homolactic fermentation to ethanol, formate, and acetoin production, with a high level of formate production even under aerobic conditions. Ldh-2 plays only a minor role in lactate production.
Ammonia-Oxidizing Bacteria and Archaea in Groundwater Treatment and Drinking Water Distribution Systems
Authors: van der Wielen Paul W. J. J. , Voost Stefan , van der Kooij Dick
Published: May 2009

The ammonia-oxidizing prokaryote (AOP) community in three groundwater treatment plants and connected distribution systems was analyzed by quantitative real-time PCR and sequence analysis targeting the
amoA
gene of ammonia-oxidizing bacteria (AOB) and archaea (AOA). Results demonstrated that AOB and AOA numbers increased during biological filtration of ammonia-rich anoxic groundwater, and AOP were responsible for ammonium removal during treatment. In one of the treatment trains at plant C, ammonia removal correlated significantly with AOA numbers but not with AOB numbers. Thus, AOA were responsible for ammonia removal in water treatment at one of the studied plants. Furthermore, an observed negative correlation between the dissolved organic carbon (DOC) concentration in the water and AOA numbers suggests that high DOC levels might reduce growth of AOA. AOP entered the distribution system in numbers ranging from 1.5 × 10
3
to 6.5 × 10
4
AOPs ml
−1
. These numbers did not change during transport in the distribution system despite the absence of a disinfectant residual. Thus, inactive AOP biomass does not seem to be degraded by heterotrophic microorganisms in the distribution system. We conclude from our results that AOA can be commonly present in distribution systems and groundwater treatment, where they can be responsible for the removal of ammonia.
Probiotic Properties of the 2-Substituted (1,3)-β-
d
-Glucan-Producing Bacterium
Pediococcus parvulus
2.6
Authors: Fernández de Palencia Pilar , Werning María Laura , Sierra-Filardi Elena , Dueñas María Teresa , Irastorza Ana , Corbí Angel L. , López Paloma
Published: May 2009

Exopolysaccharides have prebiotic potential and contribute to the rheology and texture of fermented foods. Here we have analyzed the in vitro bioavailability and immunomodulatory properties of the 2-substituted (1,3)-β-
d
-glucan-producing bacterium
Pediococcus parvulus
2.6. It resists gastrointestinal stress, adheres to Caco-2 cells, and induces the production of inflammation-related cytokines by polarized macrophages.
Parasporal Body Formation via Overexpression of the Cry10Aa Toxin of
Bacillus thuringiensis
subsp.
israelensis
, and Cry10Aa-Cyt1Aa Synergism
Authors: Hernández-Soto Alejandro , Del Rincón-Castro M. Cristina , Espinoza Ana M. , Ibarra Jorge E.
Published: May 2009

Bacillus thuringiensis
subsp.
israelensis
is the most widely used microbial control agent against mosquitoes and blackflies. Its insecticidal success is based on an arsenal of toxins, such as Cry4A, Cry4B, Cry11A, and Cyt1A, harbored in the parasporal crystal of the bacterium. A fifth toxin, Cry10Aa, is synthesized at very low levels; previous attempts to clone and express Cry10Aa were limited, and no parasporal body was formed. By using a new strategy, the whole Cry10A operon was cloned in the pSTAB vector, where both open reading frames ORF1 and ORF2 (and the gap between the two) were located, under the control of the
cyt1A
operon and the STAB-SD stabilizer sequence characteristic of this vector. Once the acrystalliferous mutant 4Q7 of
B. thuringiensis
subsp.
israelensis
was transformed with this construct, parasporal bodies were observed by phase-contrast microscopy and transmission electron microscopy. Discrete, ca. 0.9-μm amorphous parasporal bodies were observed in the mature sporangia, which were readily purified by gradient centrifugation once autolysis had occurred. Pure parasporal bodies showed two major bands of ca. 68 and 56 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. These bands were further characterized by N-terminal sequencing of tryptic fragments using matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis, which identified both bands as the products of ORF1 and ORF2, respectively. Bioassays against fourth-instar larvae of
Aedes aegypti
of spore-crystal complex and pure crystals of Cry10Aa gave estimated 50% lethal concentrations of 2,061 ng/ml and 239 ng/ml, respectively. Additionally, synergism was clearly detected between Cry10A and Cyt1A, as the synergistic levels (potentiation rates) were estimated at 13.3 for the mixture of Cyt1A crystals and Cry10Aa spore-crystal complex and 12.6 for the combination of Cyt1A and Cry10Aa pure crystals.
Production of Functionalized Biopolyester Granules by Recombinant
Lactococcus lactis
Authors: Mifune Jun , Grage Katrin , Rehm Bernd H. A.
Published: May 2009

Many bacteria are naturally capable of accumulating biopolyesters composed of 3-hydroxy fatty acids as intracellular inclusions, which serve as storage granules. Recently, these inclusions have been considered as nano-/microbeads with surface-attached proteins, which can be engineered to display various protein-based functions that are suitable for biotechnological and biomedical applications. In this study, the food-grade, generally-regarded-as-safe gram-positive organism
Lactococcus lactis
was engineered to recombinantly produce the biopolyester poly(3-hydroxybutyrate) and the respective intracellular inclusions. The codon-optimized polyhydroxybutyrate biosynthesis operon
phaCAB
from
Cupriavidus necator
was expressed using the nisin-controlled gene expression system. Recombinant
L. lactis
accumulated up to 6% (wt/wt) poly(3-hydroxybutyrate) of cellular dry weight. Poly(3-hydroxybutyrate) granules were isolated and analyzed with respect to bound proteins using biochemical methods and with respect to shape/size using transmission electron microscopy. The immunoglobulin G (IgG) binding ZZ domain of
Staphylococcus aureus
protein A was chosen as an exemplary functionality to be displayed at the granule surface by fusing it to the N terminus of the granule-associated poly(3-hydroxybutyrate) synthase. The presence of the fusion protein at the surface of isolated granules was confirmed by peptide fingerprinting using matrix-assisted laser desorption ionization-time of flight (mass spectrometry). The functionality of the ZZ domain-displaying granules was demonstrated by enzyme-linked immunosorbent assay and IgG affinity purification. In both assays, the ZZ beads from recombinant
L. lactis
performed at least equally to ZZ beads from
Escherichia coli
. Overall, in this study it was shown that recombinant
L. lactis
can be used to manufacture endotoxin-free poly(3-hydroxybutyrate) beads with surface functionalities that are suitable for biomedical applications.
Selection of Enzymes for Terminal Restriction Fragment Length Polymorphism Analysis of Fungal Internally Transcribed Spacer Sequences
Authors: Alvarado Pablo , Manjón Jose L.
Published: May 2009

Terminal restriction fragment length polymorphism (TRFLP) profiling of the internally transcribed spacer (ITS) ribosomal DNA of unknown fungal communities is currently unsupported by a broad-range enzyme-choosing rationale. An in silico study of terminal fragment size distribution was therefore performed following virtual digestion (by use of a set of commercially available 135 type IIP restriction endonucleases) of all published fungal ITS sequences putatively annealing to primers ITS1 and ITS4. Different diversity measurements were used to rank primer-enzyme pairs according to the richness and evenness that they showed. Top-performing pairs were hierarchically clustered to test for data dependency. The enzyme set composed of MaeII, BfaI, and BstNI returned much better results than randomly chosen enzyme sets in computer simulations and is therefore recommended for in vitro TRFLP profiling of fungal ITSs.
Specific In Situ Visualization of the Pathogenic Endophytic FungusAciculosporium take, the Cause of Witches’ Broom in Bamboo
Authors: Tanaka Eiji
Published: May 2009

The endophytic fungusAciculosporium take(Ascomycota;Clavicipitaceae) causes continuous shoot growth in bamboo. The colonized shoot eventually results in witches’ broom formation but maintains normal leaf arrangement and branching pattern. To analyze the mechanism of well-regulated symptom development, the location of the fungal endophytic hyphae in host tissues was visualized. A colorimetric in situ hybridization technique using a species-specific oligonucleotide probe targeting the 18S rRNA ofA. takewas used. In situ hybridization was performed on tissue sections of diseased shoots with or without external signs of fungal colonization. Specific signals were detected in intercellular spaces of the bamboo tissues. Most signals were detected in the shoot apical meristem and the leaf primordia. In addition, fewer signals were detected in the lateral buds, juvenile leaves, and stems. These results indicate thatA. takegrows endophytically, particularly in the shoot apical meristem of the host. The location ofA. takehyphae suggests that the mechanism of symptom development can be explained by the action of exogenous fungal auxin, which continuously induces primordium initiation within the host.
Succession of Bacterial Populations during Plant Residue Decomposition in Rice Field Soil
Authors: Rui Junpeng , Peng Jingjing , Lu Yahai
Published: May 2009

The incorporation of rice residues into paddy fields strongly enhances methane production and emissions. Although the decomposition processes of plant residues in rice field soil has been documented, the structure and dynamics of the microbial communities involved are poorly understood. The purpose of the present study was to determine the dynamics of short-chain fatty acids and the structure of bacterial communities during residue decomposition in a rice field soil. The soil was anaerobically incubated with the incorporation of rice root or straw residues for 90 days at three temperatures (15, 30, and 45°C). The dynamics of fatty acid intermediates showed an initial cumulative phase followed by a rapid consumption phase and a low-concentration quasi-steady state. Correspondingly, the bacterial populations displayed distinct successions during residue decomposition. Temperature showed a strong effect on the dynamics of bacterial populations. Members of
Clostridium
(clusters I and III) were most dominant in the incubations, particularly in the early successions.
Bacteroidetes
and
Chlorobi
were abundant in the later successions at 15 and 30°C, while
Acidobacteria
were selected at 45°C. We suggest that the early successional groups are responsible for the decomposition of the easily degradable fraction of residues, while the late successional groups become more important in decomposing the less-degradable or resistant fraction of plant residues. The bacterial succession probably is related to resource availability during residue decomposition. The fast-growing organisms are favored at the beginning, while the slow-growing bacteria are better adapted in the later stages, when substrate availability is limiting.