The Experts below are selected from a list of 3381 Experts worldwide ranked by ideXlab platform
Don L Devoe - One of the best experts on this subject based on the ideXlab platform.
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integrated thin film piezoelectric traveling wave ultrasonic motors
Sensors and Actuators A-physical, 2012Co-Authors: Gabriel L Smith, Ryan Q Rudy, Ronald G Polcawich, Don L DevoeAbstract:Abstract An integrated approach to the fabrication of thin-film piezoelectric traveling wave ultrasonic motors at the mm-scale is being developed for low power, high torque motors for small scale robotics, biomedical, and sensing applications. This paper describes the realization of ultrasonic motor Stators ranging in diameter from 1 to 3 mm using wafer scale MEMS fabrication techniques with lead zirconate titanate (PZT) thin films. Using laser Doppler vibrometry (LDV), controlled traveling waves were demonstrated in the bulk silicon elastic medium of the stator and the standing wave behavior was characterized for control purposes. Furthermore, the resonant modes of the fabricated Stators were modeled using finite element models, and experimental results agree well with this analysis.
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integrated thin film piezoelectric traveling wave ultrasonic motors
International Conference on Solid-State Sensors Actuators and Microsystems, 2011Co-Authors: Gabriel L Smith, Ryan Q Rudy, Don L Devoe, Ronald G PolcawichAbstract:An integrated approach to the fabrication of thin-film piezoelectric traveling wave ultrasonic motors (USMs) at the mm-scale is reported here for the first time. This paper describes the realization of ultrasonic motor Stators ranging in diameter from 1–3 mm using wafer scale MEMS fabrication techniques. Using laser Doppler vibrometry (LDV), we have demonstrated traveling waves in the bulk silicon elastic medium of the stator. Furthermore, the resonant modes of the fabricated Stators have been modeled, and experimental results agree well with these simulations.
Ryan Q Rudy - One of the best experts on this subject based on the ideXlab platform.
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integrated thin film piezoelectric traveling wave ultrasonic motors
Sensors and Actuators A-physical, 2012Co-Authors: Gabriel L Smith, Ryan Q Rudy, Ronald G Polcawich, Don L DevoeAbstract:Abstract An integrated approach to the fabrication of thin-film piezoelectric traveling wave ultrasonic motors at the mm-scale is being developed for low power, high torque motors for small scale robotics, biomedical, and sensing applications. This paper describes the realization of ultrasonic motor Stators ranging in diameter from 1 to 3 mm using wafer scale MEMS fabrication techniques with lead zirconate titanate (PZT) thin films. Using laser Doppler vibrometry (LDV), controlled traveling waves were demonstrated in the bulk silicon elastic medium of the stator and the standing wave behavior was characterized for control purposes. Furthermore, the resonant modes of the fabricated Stators were modeled using finite element models, and experimental results agree well with this analysis.
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integrated thin film piezoelectric traveling wave ultrasonic motors
International Conference on Solid-State Sensors Actuators and Microsystems, 2011Co-Authors: Gabriel L Smith, Ryan Q Rudy, Don L Devoe, Ronald G PolcawichAbstract:An integrated approach to the fabrication of thin-film piezoelectric traveling wave ultrasonic motors (USMs) at the mm-scale is reported here for the first time. This paper describes the realization of ultrasonic motor Stators ranging in diameter from 1–3 mm using wafer scale MEMS fabrication techniques. Using laser Doppler vibrometry (LDV), we have demonstrated traveling waves in the bulk silicon elastic medium of the stator. Furthermore, the resonant modes of the fabricated Stators have been modeled, and experimental results agree well with these simulations.
Gabriel L Smith - One of the best experts on this subject based on the ideXlab platform.
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integrated thin film piezoelectric traveling wave ultrasonic motors
Sensors and Actuators A-physical, 2012Co-Authors: Gabriel L Smith, Ryan Q Rudy, Ronald G Polcawich, Don L DevoeAbstract:Abstract An integrated approach to the fabrication of thin-film piezoelectric traveling wave ultrasonic motors at the mm-scale is being developed for low power, high torque motors for small scale robotics, biomedical, and sensing applications. This paper describes the realization of ultrasonic motor Stators ranging in diameter from 1 to 3 mm using wafer scale MEMS fabrication techniques with lead zirconate titanate (PZT) thin films. Using laser Doppler vibrometry (LDV), controlled traveling waves were demonstrated in the bulk silicon elastic medium of the stator and the standing wave behavior was characterized for control purposes. Furthermore, the resonant modes of the fabricated Stators were modeled using finite element models, and experimental results agree well with this analysis.
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integrated thin film piezoelectric traveling wave ultrasonic motors
International Conference on Solid-State Sensors Actuators and Microsystems, 2011Co-Authors: Gabriel L Smith, Ryan Q Rudy, Don L Devoe, Ronald G PolcawichAbstract:An integrated approach to the fabrication of thin-film piezoelectric traveling wave ultrasonic motors (USMs) at the mm-scale is reported here for the first time. This paper describes the realization of ultrasonic motor Stators ranging in diameter from 1–3 mm using wafer scale MEMS fabrication techniques. Using laser Doppler vibrometry (LDV), we have demonstrated traveling waves in the bulk silicon elastic medium of the stator. Furthermore, the resonant modes of the fabricated Stators have been modeled, and experimental results agree well with these simulations.
Judith P Armitage - One of the best experts on this subject based on the ideXlab platform.
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flagellar Stators stimulate c di gmp production by pseudomonas aeruginosa
Journal of Bacteriology, 2019Co-Authors: Amy Baker, Judith P Armitage, Shanice S Webster, Andreas Diepold, Sherry L Kuchma, Eric Bordeleau, George A OtooleAbstract:Flagellar motility is critical for surface attachment and biofilm formation in many bacteria. A key regulator of flagellar motility in Pseudomonas aeruginosa and other microbes is cyclic diguanylate (c-di-GMP). High levels of this second messenger repress motility and stimulate biofilm formation. c-di-GMP levels regulate motility in P. aeruginosa in part by influencing the localization of its two flagellar stator sets, MotAB and MotCD. Here, we show that while c-di-GMP can influence stator localization, Stators can in turn impact c-di-GMP levels. We demonstrate that the swarming motility-driving stator MotC physically interacts with the transmembrane region of the diguanylate cyclase SadC. Furthermore, we demonstrate that this interaction is capable of stimulating SadC activity. We propose a model by which the MotCD stator set interacts with SadC to stimulate c-di-GMP production under conditions not permissive to motility. This regulation implies a positive-feedback loop in which c-di-GMP signaling events cause MotCD Stators to disengage from the motor; then disengaged Stators stimulate c-di-GMP production to reinforce a biofilm mode of growth. Our studies help to define the bidirectional interactions between c-di-GMP and the flagellar machinery.IMPORTANCE The ability of bacterial cells to control motility during early steps in biofilm formation is critical for the transition to a nonmotile, biofilm lifestyle. Recent studies have clearly demonstrated the ability of c-di-GMP to control motility via a number of mechanisms, including through controlling transcription of motility-related genes and modulating motor function. Here, we provide evidence that motor components can in turn impact c-di-GMP levels. We propose that communication between motor components and the c-di-GMP synthesis machinery allows the cell to have a robust and sensitive switching mechanism to control motility during early events in biofilm formation.
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flagellar Stators stimulate c di gmp production by pseudomonas aeruginosa
bioRxiv, 2018Co-Authors: Amy Baker, Judith P Armitage, Shanice S Webster, Andreas Diepold, Sherry L Kuchma, Eric Bordeleau, George A OtooleAbstract:Abstract Flagellar motility is critical for surface attachment and biofilm formation in many bacteria. A key regulator of flagellar motility in Pseudomonas aeruginosa and other microbes is cyclic diguanylate (c-di-GMP). High levels of this second messenger repress motility and stimulate biofilm formation. C-di-GMP levels regulate motility in P. aeruginosa in part by influencing the localization of its two flagellar stator sets, MotAB and MotCD. Here we show that just as c-di-GMP can influence the Stators, Stators can impact c-di-GMP levels. We demonstrate that the swarming motility-driving stator MotC physically interacts with the transmembrane region of the diguanylate cyclase SadC. Furthermore, we demonstrate that this interaction is capable of stimulating SadC activity. We propose a model by which the MotCD stator set interacts with SadC to stimulate c-di-GMP production in conditions not permissive to motility. This regulation implies a positive feedback loop in which c-di-GMP signaling events cause MotCD Stators to disengage from the motor; then disengaged Stators stimulate c-di-GMP production to reinforce a biofilm mode of growth. Our studies help define the bidirectional interactions between c-di-GMP and the motility machinery. Importance. The ability of bacterial cells to control motility during early steps in biofilm formation is critical for the transition to a non-motile, biofilm lifestyle. Recent studies have clearly demonstrated the ability of c-di-GMP to control motility via a number of mechanisms, including through controlling transcription of motility-related genes and modulating motor function. Here we provide evidence that motor components can in turn impact c-di-GMP levels. We propose that communication between motor components and c-di-GMP synthesis machinery allows the cell to have a robust and sensitive switching mechanism to control motility during early events in biofilm formation.
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dual stator dynamics in the shewanella oneidensis mr 1 flagellar motor
Molecular Microbiology, 2015Co-Authors: Anja Paulick, Nicolas J Delalez, Richard M Berry, Judith P Armitage, Susanne Brenzinger, Bradley C Steel, Kai M ThormannAbstract:The bacterial flagellar motor is an intricate nanomachine which converts ion gradients into rotational movement. Torque is created by ion-dependent stator complexes which surround the rotor in a ring. Shewanella oneidensis MR-1 expresses two distinct types of stator units: the Na(+)-dependent PomA4 B2 and the H(+)-dependent MotA4 B2. Here, we have explored the stator unit dynamics in the MR-1 flagellar system by using mCherry-labeled PomAB and MotAB units. We observed a total of between 7 and 11 stator units in each flagellar motor. Both types of stator units exchanged between motors and a pool of stator complexes in the membrane, and the exchange rate of MotAB, but not of PomAB, units was dependent on the environmental Na(+)-levels. In 200 mM Na(+), the numbers of PomAB and MotAB units in wild-type motors was determined to be about 7:2 (PomAB:MotAB), shifting to about 6:5 without Na(+). Significantly, the average swimming speed of MR-1 cells at low Na(+) conditions was increased in the presence of MotAB. These data strongly indicate that the S. oneidensis flagellar motors simultaneously use H(+) and Na(+) driven Stators in a configuration governed by MotAB incorporation efficiency in response to environmental Na(+) levels.
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load dependent assembly of the bacterial flagellar motor
Mbio, 2013Co-Authors: Murray J Tipping, Nicolas J Delalez, Ren Lim, Richard M Berry, Judith P ArmitageAbstract:It is becoming clear that the bacterialflagellar motor output is important not only for bacterial locomotion but also for mediating the transition from liquid to surface living. The output of theflagellar motor changes with the mechanical load placed on it by the external environment: at a higher load, the motor runs more slowly and produces higher torque. Here we show that the number of torque-generating units bound to theflagellar motor also depends on the external mechanical load, with fewer Stators at lower loads. Stalled motors contained at least as many Stators as rotating motors at high load, indicating that rotation is unnecessary for stator binding. Mutant Stators incapable of generating torque could not be detected around the motor. We speculate that a component of the bacterialflagellar motor senses external load and mediates the strength of stator binding to the rest of the motor. IMPORTANCE The transition between liquid living and surface living is important in the life cycles of many bacteria. In this paper, we describe how theflagellar motor, used by bacteria for locomotion through liquid media and across solid surfaces, is capable of adjusting the number of bound stator units to better suit the external load conditions. By stalling motors using external mag- neticfields, we also show that rotation is not required for maintenance of Stators around the motor; instead, torque production is the essential factor for motor stability. These new results, in addition to previous data, lead us to hypothesize that the motor Stators function as mechanosensors as well as functioning as torque-generating units.
George A Otoole - One of the best experts on this subject based on the ideXlab platform.
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flagellar Stators stimulate c di gmp production by pseudomonas aeruginosa
Journal of Bacteriology, 2019Co-Authors: Amy Baker, Judith P Armitage, Shanice S Webster, Andreas Diepold, Sherry L Kuchma, Eric Bordeleau, George A OtooleAbstract:Flagellar motility is critical for surface attachment and biofilm formation in many bacteria. A key regulator of flagellar motility in Pseudomonas aeruginosa and other microbes is cyclic diguanylate (c-di-GMP). High levels of this second messenger repress motility and stimulate biofilm formation. c-di-GMP levels regulate motility in P. aeruginosa in part by influencing the localization of its two flagellar stator sets, MotAB and MotCD. Here, we show that while c-di-GMP can influence stator localization, Stators can in turn impact c-di-GMP levels. We demonstrate that the swarming motility-driving stator MotC physically interacts with the transmembrane region of the diguanylate cyclase SadC. Furthermore, we demonstrate that this interaction is capable of stimulating SadC activity. We propose a model by which the MotCD stator set interacts with SadC to stimulate c-di-GMP production under conditions not permissive to motility. This regulation implies a positive-feedback loop in which c-di-GMP signaling events cause MotCD Stators to disengage from the motor; then disengaged Stators stimulate c-di-GMP production to reinforce a biofilm mode of growth. Our studies help to define the bidirectional interactions between c-di-GMP and the flagellar machinery.IMPORTANCE The ability of bacterial cells to control motility during early steps in biofilm formation is critical for the transition to a nonmotile, biofilm lifestyle. Recent studies have clearly demonstrated the ability of c-di-GMP to control motility via a number of mechanisms, including through controlling transcription of motility-related genes and modulating motor function. Here, we provide evidence that motor components can in turn impact c-di-GMP levels. We propose that communication between motor components and the c-di-GMP synthesis machinery allows the cell to have a robust and sensitive switching mechanism to control motility during early events in biofilm formation.
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flagellar Stators stimulate c di gmp production by pseudomonas aeruginosa
bioRxiv, 2018Co-Authors: Amy Baker, Judith P Armitage, Shanice S Webster, Andreas Diepold, Sherry L Kuchma, Eric Bordeleau, George A OtooleAbstract:Abstract Flagellar motility is critical for surface attachment and biofilm formation in many bacteria. A key regulator of flagellar motility in Pseudomonas aeruginosa and other microbes is cyclic diguanylate (c-di-GMP). High levels of this second messenger repress motility and stimulate biofilm formation. C-di-GMP levels regulate motility in P. aeruginosa in part by influencing the localization of its two flagellar stator sets, MotAB and MotCD. Here we show that just as c-di-GMP can influence the Stators, Stators can impact c-di-GMP levels. We demonstrate that the swarming motility-driving stator MotC physically interacts with the transmembrane region of the diguanylate cyclase SadC. Furthermore, we demonstrate that this interaction is capable of stimulating SadC activity. We propose a model by which the MotCD stator set interacts with SadC to stimulate c-di-GMP production in conditions not permissive to motility. This regulation implies a positive feedback loop in which c-di-GMP signaling events cause MotCD Stators to disengage from the motor; then disengaged Stators stimulate c-di-GMP production to reinforce a biofilm mode of growth. Our studies help define the bidirectional interactions between c-di-GMP and the motility machinery. Importance. The ability of bacterial cells to control motility during early steps in biofilm formation is critical for the transition to a non-motile, biofilm lifestyle. Recent studies have clearly demonstrated the ability of c-di-GMP to control motility via a number of mechanisms, including through controlling transcription of motility-related genes and modulating motor function. Here we provide evidence that motor components can in turn impact c-di-GMP levels. We propose that communication between motor components and c-di-GMP synthesis machinery allows the cell to have a robust and sensitive switching mechanism to control motility during early events in biofilm formation.
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roles for flagellar Stators in biofilm formation by pseudomonas aeruginosa
Research in Microbiology, 2007Co-Authors: Christine M Toutain, Nicky C Caizza, Michael E Zegans, George A OtooleAbstract:While Pseudomonas aeruginosa has only a single flagellum, its genome encodes two flagellar Stators, called MotAB and MotCD. Here we report that despite no apparent alterations in swimming motility, mutations in either the MotAB or the MotCD stator render the strains defective for biofilm formation in both static and flow cell systems. Our data suggest distinct roles for the Stators in early biofilm formation, with both the MotAB and MotCD Stators playing a role in initial polar attachment of the bacterial cell to the surface (reversible attachment) and the MotAB stator also participating in the downstream adherence event of irreversible attachment. We also show that the initial polar attachment of P. aeruginosa to two different abiotic surfaces occurs largely at the flagellated end of the cell, a finding that should help develop models for early attachment events. Interestingly, in flowing conditions, a mutation in either stator alone revealed a more severe biofilm defect than mutating both Stators or mutating the flagellum. Our data suggest that defects in biofilm formation observed for the stator mutants may be in part due to impacting flagellar reversal rates.
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evidence for two flagellar Stators and their role in the motility of pseudomonas aeruginosa
Journal of Bacteriology, 2005Co-Authors: Christine M Toutain, Michael E Zegans, George A OtooleAbstract:Pseudomonas aeruginosa is a ubiquitous bacterium capable of twitching, swimming, and swarming motility. In this study, we present evidence that P. aeruginosa has two flagellar Stators, conserved in all pseudomonads as well as some other gram-negative bacteria. Either stator is sufficient for swimming, but both are necessary for swarming motility under most of the conditions tested, suggesting that these two Stators may have different roles in these two types of motility.
