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https://www.readbyqxmd.com/read/28230350/cyclic-voltammetry-probe-approach-curves-with-alkali-amalgams-at-mercury-sphere-cap-scanning-electrochemical-microscopy-probes
#1
Zachary J Barton, Joaquín Rodríguez-López
We report a method of precisely positioning a Hg-based ultramicroelectrode (UME) for scanning electrochemical microscopy (SECM) investigations of any substrate. Hg-based probes are capable of performing amalgamation reactions with metal cations, which avoid unwanted side reactions and positive feedback mechanisms that can prove problematic for traditional probe positioning methods. However, prolonged collection of ions eventually leads to saturation of the amalgam accompanied by irreversible loss of Hg. In order to obtain negative feedback positioning control without risking damage to the SECM probe, we implement cyclic voltammetry probe approach surfaces (CV-PASs), consisting of CVs performed between incremental motor movements...
February 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28230090/advanced-retarded-differential-equations-in-quantum-photonic-systems
#2
Unai Alvarez-Rodriguez, Armando Perez-Leija, Iñigo L Egusquiza, Markus Gräfe, Mikel Sanz, Lucas Lamata, Alexander Szameit, Enrique Solano
We propose the realization of photonic circuits whose dynamics is governed by advanced-retarded differential equations. Beyond their mathematical interest, these photonic configurations enable the implementation of quantum feedback and feedforward without requiring any intermediate measurement. We show how this protocol can be applied to implement interesting delay effects in the quantum regime, as well as in the classical limit. Our results elucidate the potential of the protocol as a promising route towards integrated quantum control systems on a chip...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28229577/maximal-aerobic-capacity-can-be-increased-by-enhancing-performers-expectancies
#3
Jeff Montes, Gabriele Wulf, James W Navalta
BACKGROUND: Maximum aerobic capacity (VO2max) is widely accepted as the best measure of cardiovascular fitness and aerobic power. The present study investigated whether enhancing participants' performance expectancies through positive social-comparative feedback would increase VO2max. METHODS: Participants were experienced runners who regularly ran for exercise or competitively. All participants completed two VO2max tests within a 2-week period at similar times of the day...
February 22, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28229193/osseointegrated-prostheses-for-rehabilitation-following-amputation-the-pioneering-swedish-model
#4
Yan Li, Rickard Brånemark
The direct attachment of osseointegrated (OI) prostheses to the skeleton avoids the inherent problems of socket suspension. It also provides physiological weight bearing, improved range of motion in the proximal joint, as well as osseoperceptive sensory feedback, enabling better control of the artificial limbs by amputees. The present article briefly reviews the pioneering efforts on extremity osseointegration surgeries in Sweden and the development of the OPRA (Osseointegrated Prostheses for the Rehabilitation of Amputees) program...
February 22, 2017: Der Unfallchirurg
https://www.readbyqxmd.com/read/28229113/social-stress-models-in-rodents-towards-enhanced-validity
#5
REVIEW
J M Koolhaas, S F de Boer, B Buwalda, P Meerlo
Understanding the role of the social environment in the development of stress related diseases requires a more fundamental understanding of stress. Stress includes not only the stimulus and the response but also the individual appraisal of the situation. The social environment is not only essential for survival it is at the same time an important source of stressors. This review discusses the social stress concept, how it has been studied in rodents in the course of time and some more recent insights into the appraisal process...
February 2017: Neurobiology of Stress
https://www.readbyqxmd.com/read/28228548/contact-guidance-requires-spatial-control-of-leading-edge-protrusion
#6
G R Ramirez-San Juan, P W Oakes, M L Gardel
In vivo, geometric cues from the extra-cellular matrix (ECM) are critical for the regulation of cell shape, adhesion and migration. During contact guidance, the fibrillar architecture of the ECM promotes an elongated cell shape and migration along the fibrils. The subcellular mechanisms by which cells sense ECM geometry and translate it into changes in shape and migration direction, are not understood. Here, we pattern linear fibronectin features to mimic fibrillar ECM and elucidate the mechanisms of contact guidance...
February 22, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28228546/a-minimal-actomyosin-based-model-predicts-the-dynamics-of-filopodia-on-neuronal-dendrites
#7
Olena O Marchenko, Sulagna Das, Ji Yu, Igor L Novak, Vladimir I Rodionov, Nadia Efimova, Tatyana Svitkina, Charles W Wolgemuth, Leslie M Loew
Dendritic filopodia are actin-filled dynamic subcellular structures that sprout on neuronal dendrites during neurogenesis. The exploratory motion of the filopodia is crucial for synaptogenesis but the underlying mechanisms are poorly understood. To study the filopodial motility, we collected and analyzed image data on filopodia in cultured rat hippocampal neurons. We hypothesized that mechanical feedback among the actin retrograde flow, myosin activity and substrate adhesion gives rise to various filopodial behaviors...
February 22, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28228491/maldi-tof-alone-versus-maldi-tof-combined-with-real-time-antimicrobial-stewardship-interventions-on-time-to-optimal-antimicrobial-therapy-in-patients-with-positive-blood-cultures
#8
Maya Beganovic, Michael Costello, Sarah M Wieczorkiewicz
Introduction: Matrix-assisted laser desorption ionization time of flight (MALDI-TOF) decreases time to organism identification and improves clinical and financial outcomes. The purpose of this study was to evaluate the impact of MALDI-TOF alone vs MALDI-TOF combined with real-time, pharmacist-driven, antimicrobial stewardship (AMS) intervention on patient outcomes.Methods: This single-center, pre-post quasi-experimental study evaluated hospitalized patients with positive blood cultures identified via MALDI-TOF combined with prospective AMS intervention, compared to a control cohort with MALDI-TOF identification without AMS intervention...
February 22, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28228280/autocrine-loop-involving-il-6-family-member-lif-lif-receptor-and-stat4-drives-sustained-fibroblast-production-of-inflammatory-mediators
#9
Hung N Nguyen, Erika H Noss, Fumitaka Mizoguchi, Christine Huppertz, Kevin S Wei, Gerald F M Watts, Michael B Brenner
Fibroblasts are major contributors to and regulators of inflammation and dominant producers of interleukin-6 (IL-6) in inflammatory diseases like rheumatoid arthritis. Yet, compared to leukocytes, the regulation of inflammatory pathways in fibroblasts is largely unknown. Here, we report that analyses of genes coordinately upregulated with IL-6 pointed to STAT4 and leukemia inhibitory factor (LIF) as potentially linked. Gene silencing revealed that STAT4 was required for IL-6 transcription. STAT4 was recruited to the IL-6 promoter after fibroblast activation, and LIF receptor (LIFR) and STAT4 formed a molecular complex that, together with JAK1 and TYK2 kinases, controlled STAT4 activation...
February 21, 2017: Immunity
https://www.readbyqxmd.com/read/28227970/combining-a-hybrid-robotic-system-with-a-bain-machine-interface-for-the-rehabilitation-of-reaching-movements-a-case-study-with-a-stroke-patient
#10
F Resquin, J Ibanez, J Gonzalez-Vargas, F Brunetti, I Dimbwadyo, S Alves, L Carrasco, L Torres, Jose Luis Pons, F Resquin, J Ibañez, J Gonzalez-Vargas, F Brunetti, I Dimbwadyo, S Alves, L Carrasco, L Torres, Jose Luis Pons, S Alves, Jose Luis Pons, F Brunetti, J Gonzalez-Vargas, F Resquin, I Dimbwadyo, L Carrasco, L Torres, J Ibanez
Reaching and grasping are two of the most affected functions after stroke. Hybrid rehabilitation systems combining Functional Electrical Stimulation with Robotic devices have been proposed in the literature to improve rehabilitation outcomes. In this work, we present the combined use of a hybrid robotic system with an EEG-based Brain-Machine Interface to detect the user's movement intentions to trigger the assistance. The platform has been tested in a single session with a stroke patient. The results show how the patient could successfully interact with the BMI and command the assistance of the hybrid system with low latencies...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227964/cross-entropy-optimization-for-neuromodulation
#11
Harleen K Brar, Yunpeng Pan, Babak Mahmoudi, Evangelos A Theodorou, Harleen K Brar, Yunpeng Pan, Babak Mahmoudi, Evangelos A Theodorou, Yunpeng Pan, Harleen K Brar, Babak Mahmoudi, Evangelos A Theodorou
This study presents a reinforcement learning approach for the optimization of the proportional-integral gains of the feedback controller represented in a computational model of epilepsy. The chaotic oscillator model provides a feedback control systems view of the dynamics of an epileptic brain with an internal feedback controller representative of the natural seizure suppression mechanism within the brain circuitry. Normal and pathological brain activity is simulated in this model by adjusting the feedback gain values of the internal controller...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227942/unified-phase-variables-of-relative-degree-two-for-human-locomotion
#12
Dario J Villarreal, Robert D Gregg, Dario J Villarreal, Robert D Gregg, Robert D Gregg, Dario J Villarreal
A starting point to achieve stable locomotion is synchronizing the leg joint kinematics during the gait cycle. Some biped robots parameterize a nonlinear controller (e.g., input-output feedback linearization) whose main objective is to track specific kinematic trajectories as a function of a single mechanical variable (i.e., a phase variable) in order to allow the robot to walk. A phase variable capable of parameterizing the entire gait cycle, the hip phase angle, has been used to control wearable robots and was recently shown to provide a robust representation of the phase of human gait...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227810/noninvasive-eeg-correlates-of-overground-and-stair-walking
#13
Justin A Brantley, Trieu Phat Luu, Recep Ozdemir, Fangshi Zhu, Anna T Winslow, Helen Huang, Jose L Contreras-Vidal, Justin A Brantley, Trieu Phat Luu, Recep Ozdemir, Fangshi Zhu, Anna T Winslow, Helen Huang, Jose L Contreras-Vidal, Fangshi Zhu, Recep Ozdemir, Justin A Brantley, Helen Huang, Anna T Winslow, Jose L Contreras-Vidal, Trieu Phat Luu
Automated walking intention detection remains a challenge in lower-limb neuroprosthetic systems. Here, we assess the feasibility of extracting motor intent from scalp electroencephalography (EEG). First, we evaluated the corticomuscular coherence between central EEG electrodes (C1, Cz, C2) and muscles of the shank and thigh during walking on level ground and stairs. Second, we trained decoders to predict the linear envelope of the surface electromyogram (EMG). We observed significant EEG-led corticomuscular coupling between electrodes and sEMG (tibialis anterior) in the high delta (3-4 Hz) and low theta (4-5 Hz) frequency bands during level walking, indicating efferent signaling from the cortex to peripheral motor neurons...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227740/influence-of-force-feedback-on-grasp-force-modulation-in-prosthetic-applications-a-preliminary-study
#14
Sasha B Godfrey, Matteo Bianchi, Antonio Bicchi, Marco Santello, Sasha B Godfrey, Matteo Bianchi, Antonio Bicchi, Marco Santello, Marco Santello, Antonio Bicchi, Sasha B Godfrey, Matteo Bianchi
In typical movement, humans use a combination of feed-forward and feedback motor control strategies to interact with the world around them. However, when sensory input is impaired or absent, as in the case of various neuropathies or amputation, the ability to perform everyday tasks, like modulating grip force to object weight, can be affected. In this study, we show the results of a preliminary study using a pressure cuff-like force feedback device (CUFF) with the SoftHand Pro (SHP) prosthetic hand. Subjects lifted an object of various weights using their own hand, with the SHP without feedback, and the SHP with force feedback...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227693/using-bioimpedance-spectroscopy-parameters-as-real-time-feedback-during-tdcs
#15
Isar Nejadgholi, Herschel Caytak, Miodrag Bolic, Isar Nejadgholi, Herschel Caytak, Miodrag Bolic, Isar Nejadgholi, Miodrag Bolic, Herschel Caytak
An exploratory analysis is carried out to investigate the feasibility of using BioImpedance Spectroscopy (BIS) parameters, measured on scalp, as real-time feedback during Transcranial Direct Current Stimulation (tDCS). TDCS is shown to be a potential treatment for neurological disorders. However, this technique is not considered as a reliable clinical treatment, due to the lack of a measurable indicator of treatment efficacy. Although the voltage that is applied on the head is very simple to measure during a tDCS session, changes of voltage are difficult to interpret in terms of variables that affect clinical outcome...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227685/graphical-user-interface-for-a-robotic-workstation-in-a-surgical-environment
#16
A Bielski, C P Lohmann, M Maier, D Zapp, M A Nasseri, A Bielski, C P Lohmann, M Maier, D Zapp, M A Nasseri, M A Nasseri, M Maier, D Zapp, C P Lohmann, A Bielski
Surgery using a robotic system has proven to have significant potential but is still a highly challenging task for the surgeon. An eye surgery assistant has been developed to eliminate the problem of tremor caused by human motions endangering the outcome of ophthalmic surgery. In order to exploit the full potential of the robot and improve the workflow of the surgeon, providing the ability to change control parameters live in the system as well as the ability to connect additional ancillary systems is necessary...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227672/robot-assisted-microsurgical-forceps-with-haptic-feedback-for-transoral-laser-microsurgery
#17
Nikhil Deshpande, Manish Chauhan, Claudio Pacchierotti, Domenico Prattichizzo, Darwin G Caldwell, Leonardo S Mattos, Nikhil Deshpande, Manish Chauhan, Claudio Pacchierotti, Domenico Prattichizzo, Darwin G Caldwell, Leonardo S Mattos, Darwin G Caldwell, Leonardo S Mattos, Nikhil Deshpande, Domenico Prattichizzo, Manish Chauhan, Claudio Pacchierotti
In this paper, a novel, motorized, multi-degrees-of-freedom (DoF), microsurgical forceps tool is presented, which is based on a master-slave teleoperation architecture. The slave device is a 7-DoF manipulator with: (i) 6-DoF positioning and orientation, (ii) 1 open/close gripper DoF; and (iii) an integrated force/torque sensor for tissue grip-force measurement. The master device is a 7-DoF haptic interface which teleoperates the slave device, and provides haptic feedback in its gripper interface. The combination of the device and the surgeon interface replaces the manual, hand-held device providing easy-to-use and ergonomic tissue control, simplifying the surgical tasks...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227668/mental-stress-grading-based-on-fnirs-signals
#18
Fares Al-Shargie, Tong Boon Tang, Masashi Kiguchi, Fares Al-Shargie, Tong Boon Tang, Masashi Kiguchi, Masashi Kiguchi, Tong Boon Tang, Fares Al-Shargie
In this study, we propose functional near infrared spectroscopy (fNIRS) to objectively grade different levels of mental stress. The levels of stress were set based on the difficulty of arithmetic task, time pressure and negative feedback about peer performance. We examined the proposed approach on twelve human subjects using the Montreal Imaging Stress Task. The experiment results revealed a reduction in cortical activation at prefrontal cortex when stressed, and the differences in hemodynamic response between control condition and under stress were significant for arithmetic difficulty level one, two and three, respectively, (p = 0...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227662/towards-synergistic-control-of-hands-on-needle-insertion-with-automated-needle-steering-for-mri-guided-prostate-interventions
#19
Marek Wartenberg, Niravkumar Patel, Gang Li, Gregory S Fischer, Marek Wartenberg, Niravkumar Patel, Gang Li, Gregory S Fischer, Niravkumar Patel, Marek Wartenberg, Gregory S Fischer, Gang Li
A significant hurdle of accurate needle tip placement in percutaneous needle-based prostate interventions is unmodeled needle deflection and tissue deformation during insertion. This paper introduces a robotic platform for developing synergistic, cooperatively controlled needle insertion algorithms decoupled from closed-loop image-guided needle steering. Shared control of the surgical workspace through human-robot synergy creates a balance between the accuracy of robotic autonomy while still providing ultimate control of the procedure to the physician...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227645/myoelectric-intuitive-control-and-transcutaneous-electrical-stimulation-of-the-forearm-for-vibrotactile-sensation-feedback-applied-to-a-3d-printed-prosthetic-hand
#20
Enrique I Germany, Esteban J Pino, Pablo E Aqueveque, Enrique I Germany, Esteban J Pino, Pablo E Aqueveque, Enrique I Germany, Pablo E Aqueveque, Esteban J Pino
This paper presents the development of a myoelectric prosthetic hand based on a 3D printed model. A myoelectric control strategy based on artificial neural networks is implemented on a microcontroller for online position estimation. Position estimation performance achieves a correlation index of 0.78. Also a study involving transcutaneous electrical stimulation was performed to provide tactile feedback. A series of stimulations with controlled parameters were tested on five able-body subjects. A single channel stimulator was used, positioning the electrodes 8 cm on the wrist over the ulnar and median nerve...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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