Spatio-Temporal Constrained Human Trajectory Generation from the PIR Motion Detector Sensor Network Data: A Geometric Algebra Approach.

PubMed

Yu, Zhaoyuan; Yuan, Linwang; Luo, Wen; Feng, Linyao; Lv, Guonian

2015-12-30

Passive infrared (PIR) motion detectors, which can support long-term continuous observation, are widely used for human motion analysis. Extracting all possible trajectories from the PIR sensor networks is important. Because the PIR sensor does not log location and individual information, none of the existing methods can generate all possible human motion trajectories that satisfy various spatio-temporal constraints from the sensor activation log data. In this paper, a geometric algebra (GA)-based approach is developed to generate all possible human trajectories from the PIR sensor network data. Firstly, the representation of the geographical network, sensor activation response sequences and the human motion are represented as algebraic elements using GA. The human motion status of each sensor activation are labeled using the GA-based trajectory tracking. Then, a matrix multiplication approach is developed to dynamically generate the human trajectories according to the sensor activation log and the spatio-temporal constraints. The method is tested with the MERL motion database. Experiments show that our method can flexibly extract the major statistical pattern of the human motion. Compared with direct statistical analysis and tracklet graph method, our method can effectively extract all possible trajectories of the human motion, which makes it more accurate. Our method is also likely to provides a new way to filter other passive sensor log data in sensor networks.

Use of inpatient continuous passive motion versus no CPM in computer-assisted total knee arthroplasty.

PubMed

Alkire, Martha R; Swank, Michael L

2010-01-01

Continuous passive motion (CPM) has shown positive effects on tissue healing, edema, hemarthrosis, and joint function (L. Brosseau et al., 2004). CPM has also been shown to increase short-term early flexion and decrease length of stay (LOS) ( L. Brosseau et al., 2004; C. M. Chiarello, C. M. S. Gundersen, & T. O'Halloran, 2004). The benefits of CPM for the population of patients undergoing computer-assisted total knee arthroplasty (TKA) have not been examined. The primary objective of this study was to determine whether the use of CPM following computer-assisted TKA resulted in differences in range of motion, edema/drainage, functional ability, and pain. This was an experimental, prospective, randomized study of patients undergoing unilateral, computer-assisted TKA. The experimental group received CPM thrice daily and physical therapy (PT) twice daily during their hospitalization. The control group received PT twice daily and no CPM during the hospital stay. Both groups received PT after discharge. Measurement included Knee Society scores, Western Ontario McMaster Osteoarthritis Index values, range of motion, knee circumference, and HemoVac drainage. Data were collected at various intervals from preoperatively through 3 months. Although the control group was found to be higher functioning preoperatively, there was no statistically significant difference in flexion, edema or drainage, function, or pain between groups through the 3-month study period.

Passive lumbar tissue loading during trunk bending at three speeds: An in vivo study.

PubMed

Ning, Xiaopeng; Nussbaum, Maury A

2015-08-01

Low back disorders are closely related with the magnitude of mechanical loading on human spine. However, spinal loading contributed by the lumbar passive tissues is still not well understood. In this study, the effect of motion speed on lumbar passive moment output was investigated. In addition, the increase of lumbar passive moment during trunk bending was modeled. Twelve volunteers performed trunk-bending motions at three different speeds. Trunk kinematics and muscle activities were collected and used to estimate instantaneous spinal loading and the corresponding lumbar passive moment. The lumbar passive moments at different ranges of trunk motion were compared at different speed levels and the relationship between lumbar passive moment lumbar flexion was modeled. A non-linear, two-stage pattern of increase in lumbar passive moment was evident during trunk flexion. However, the effect of motion speed was not significant on lumbar passive moments or any of the model parameters. As reported previously, distinct lumbar ligaments may begin to generate tension at differing extents of trunk flexion, and this could be the cause of the observed two-stage increasing pattern of lumbar passive moment. The current results also suggest that changes in tissue strain rate may not have a significant impact on the total passive moment output at the relatively slow trunk motions examined here. Copyright © 2015 Elsevier Ltd. All rights reserved.

Active Brownian particles escaping a channel in single file.

PubMed

Locatelli, Emanuele; Baldovin, Fulvio; Orlandini, Enzo; Pierno, Matteo

2015-02-01

Active particles may happen to be confined in channels so narrow that they cannot overtake each other (single-file conditions). This interesting situation reveals nontrivial physical features as a consequence of the strong interparticle correlations developed in collective rearrangements. We consider a minimal two-dimensional model for active Brownian particles with the aim of studying the modifications introduced by activity with respect to the classical (passive) single-file picture. Depending on whether their motion is dominated by translational or rotational diffusion, we find that active Brownian particles in single file may arrange into clusters that are continuously merging and splitting (active clusters) or merely reproduce passive-motion paradigms, respectively. We show that activity conveys to self-propelled particles a strategic advantage for trespassing narrow channels against external biases (e.g., the gravitational field).

Active Brownian particles escaping a channel in single file

NASA Astrophysics Data System (ADS)

Locatelli, Emanuele; Baldovin, Fulvio; Orlandini, Enzo; Pierno, Matteo

2015-02-01

Active particles may happen to be confined in channels so narrow that they cannot overtake each other (single-file conditions). This interesting situation reveals nontrivial physical features as a consequence of the strong interparticle correlations developed in collective rearrangements. We consider a minimal two-dimensional model for active Brownian particles with the aim of studying the modifications introduced by activity with respect to the classical (passive) single-file picture. Depending on whether their motion is dominated by translational or rotational diffusion, we find that active Brownian particles in single file may arrange into clusters that are continuously merging and splitting (active clusters) or merely reproduce passive-motion paradigms, respectively. We show that activity conveys to self-propelled particles a strategic advantage for trespassing narrow channels against external biases (e.g., the gravitational field).

Self-propelled colloidal particle near a planar wall: A Brownian dynamics study

NASA Astrophysics Data System (ADS)

Mozaffari, Ali; Sharifi-Mood, Nima; Koplik, Joel; Maldarelli, Charles

2018-01-01

Miniaturized, self-propelled locomotors use chemo-mechanical transduction mechanisms to convert fuel in the environment to autonomous motion. Recent experimental and theoretical studies demonstrate that these autonomous engines can passively follow the contours of solid boundaries they encounter. Boundary guidance, however, is not necessarily stable: Mechanical disturbances can cause the motor to hydrodynamically depart from the passively guided pathway. Furthermore, given the scaled-down size of micromotors (typically 100 nm to10 μ m ), Brownian thermal fluctuation forces are necessarily important, and these stochastic forces can randomize passively steered trajectories. Here we examine theoretically the stability of boundary-guided motion of micromotors along infinite planar walls to mechanical disturbances and to Brownian forces. Our aim is to understand under what conditions this passively guided motion is stable. We choose a locomotor design in which spherical colloids are partially coated with a catalytic cap that reacts with solute to produce a product. The product is repelled from the particle surface, causing the particle to move with the inert face at the front (autonomous motion via self-diffusiophoresis). When propelled towards a planar wall, deterministic hydrodynamic studies demonstrate that these locomotors can exhibit, for large enough cap sizes, steady trajectories in which the particle either skims unidirectionally along the surface at a constant distance from the wall or becomes stationary. We first investigate the linear hydrodynamic stability of these states by expanding the equations of motion about the states, and we find that linear perturbations decay exponentially in time. We then study the effects of thermal fluctuations by formulating a Langevin equation for the particle motion which includes the Brownian stochastic force. The Péclet number scales the ratio of deterministic to Brownian forces, where Pe =π μ a2v˜c/kBT and a denotes the colloid radius, μ the continuous phase viscosity, v˜c the characteristic diffusiophoretic velocity, and kBT the thermal energy. The skimming and stationary states are found to persist for Pe above 103. At Pe below 200, the trajectory of a locomotor approaching the wall is unpredictable. We present representative individual trajectories along with probability distributions for statistical ensembles of particles, quantifying the effects of thermal fluctuations and illustrating the transition from unpredictable to passively guided motion.

The effects of passive stretching plus vibration on strength and activation of the plantar flexors.

PubMed

Miller, Jonathan D; Herda, Trent J; Trevino, Michael A; Mosier, Eric M

2016-09-01

This study examined the effects of passive stretching only (PS+CON) and passive stretching with the addition of continuous vibration (VIB) during post-passive stretching tests (PS+VIB) on peak torque (PT), percent voluntary inactivation (%VI), single stimulus twitch torque (TTSINGLE), and doublet stimuli twitch torque (TTDOUBLET) of the plantar flexors at a short (20° plantar flexion (PF)) and long muscle length (15° dorsiflexion (DF)). Fourteen healthy men (age = 22 ± 3 years) performed isometric maximal voluntary contractions at PF and DF, and passive range of motion (PROM) assessments before and after 8 × 30-s passive stretches without (PS+CON) or with VIB (PS+VIB) administered continuously throughout post-passive stretching tests. The passive properties of the muscle tendon unit were assessed pre- and post-passive stretching via PROM, passive torque (PASSTQ), and musculotendinous stiffness (MTS) measurements. PT, TTSINGLE, and TTDOUBLET decreased, whereas, %VI increased following passive stretching at PF and DF (P < 0.05) with no significant differences between PS+CON and PS+VIB. PASSTQ and MTS decreased while PROM increased post-passive stretching during both trials (P < 0.05). The stretching-induced force/torque deficit and increases in %VI were evident following passive stretching at short and long muscle lengths. Although not statistically significant, effect size calculations suggested large and moderate differences in the absolute changes in PT (Cohen's d = 1.14) and %VI (Cohen's d = 0.54) from pre- to post-passive stretching between treatments, with PS+VIB having greater decreases of PT and higher %VI than PS+CON. The decrement in PT following passive stretching may be primarily neural in origin.

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection.

PubMed

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-12-21

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate.

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection †

PubMed Central

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-01-01

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate. PMID:26703612

Suppressing turbulence of self-propelling rods by strongly coupled passive particles.

PubMed

Su, Yen-Shuo; Wang, Hao-Chen; I, Lin

2015-03-01

The strong turbulence suppression, mainly for large-scale modes, of two-dimensional self-propelling rods, by increasing the long-range coupling strength Γ of low-concentration passive particles, is numerically demonstrated. It is found that large-scale collective rod motion in forms of swirls or jets is mainly contributed from well-aligned dense patches, which can push small poorly aligned rod patches and uncoupled passive particles. The more efficient momentum transfer and dissipation through increasing passive particle coupling leads to the formation of a more ordered and slowed down network of passive particles, which competes with coherent dense active rod clusters. The frustration of active rod alignment ordering and coherent motion by the passive particle network, which interrupt the inverse cascading of forming large-scale swirls, is the key for suppressing collective rod motion with scales beyond the interpassive distance, even in the liquid phase of passive particles. The loosely packed active rods are weakly affected by increasing passive particle coupling due to the weak rod-particle interaction. They mainly contribute to the small-scale modes and high-speed motion.

Continuous passive motion and physical therapy (CPM) versus physical therapy (PT) versus delayed physical therapy (DPT) after surgical release for elbow contractures; a study protocol for a prospective randomized controlled trial.

PubMed

Viveen, Jetske; Doornberg, Job N; Kodde, Izaak F; Goossens, Pjotr; Koenraadt, Koen L M; The, Bertram; Eygendaal, Denise

2017-11-22

The elbow is prone to stiffness after trauma. To regain functional elbow motion several conservative- and surgical treatment options are available. Conservative treatment includes physical therapy, intra-articular injections with corticosteroids and a static progressive or dynamic splinting program. If conservative treatment fails, an operative release of the posttraumatic stiff elbow is often performed. The best Evidence-Based rehabilitation protocol for patients after an operative release is unknown to date and differs per surgeon, hospital and country. Options include early- or delayed motion supervised by a physical therapist, immediate continuous passive motion (CPM), (night) splinting and a static progressive or dynamic splinting program. The SET-Study (Stiff Elbow Trial) is a single-centre, prospective, randomized controlled trial. The primary objective of this study is to compare the active Range of Motion (ROM) (flexion arc and rotational arc) twelve months after surgery between three groups. The first group will receive in-hospital CPM in combination with early motion Physical Therapy (PT) supervised by a physical therapist, the second group will receive only in-hospital early motion PT supervised by a physical therapist and the third group will receive outpatient supervised PT from postoperative day seven till ten. Secondary outcome measures will be Patient Reported Outcome Measures (PROMs) including the Mayo Elbow Performance Score (MEPS), the Oxford Elbow Score (OES), the quick Disabilities of Arm, Shoulder and Hand (qDASH) score, Visual Analogue pain Scale in rest and activity (VAS), Pain Catastrophizing Scale (PCS), the Short Form (SF)-36, the Centre for Epidemiological Studies Depression Scale Revised (CESD-R) and the Work Rehabilitation Questionnaire (WORQ) for the upper limb. A successful completion of this trial will provide evidence on the best rehabilitation protocol in order to (re)gain optimal motion after surgical release of the stiff elbow. The trial is registered at the Dutch Trial Register: NTR6067 , 31-8-2016.

Measurement of the passive stiffness of ankle joint in 3 DOF using stewart platform type ankle foot device.

PubMed

Nomura, Kenta; Yonezawa, Teru; Mizoguchi, Hiroshi; Takemura, Hiroshi

2016-08-01

This paper presents a method to measure the passive stiffness of an ankle joint in three degrees of freedom (DOF) under two motion speeds (1 Hz and 5 degree/s) using a developed Stewart platform-type device. The developed device can reproduce input motions of the foot in 6 DOF by controlling six pneumatic linear motion actuators. We used the device to measure the passive stiffness of an ankle joint undergoing three kinds of motion, namely dorsi-plantar flexion, inversion-eversion, and adduction-abduction. The measured values of the passive stiffness of the ankle joint in dorsiflexion that we obtained agreed well with that obtained in a previous study, indicating that the developed device is useful for measuring the passive stiffness of ankle joint. In addition, the developed device can be used to measure the stiffness in inversion-eversion and adduction-abduction motions as well, parameters that have never been measured. The results we obtained demonstrated certain interesting features as we varied both the direction and pace of motion (e.g., there were significant differences in the stiffness not only between adduction and abduction during the faster pace, but also between these and the other motions).

Towards breaking the spatial resolution barriers: An optical flow and super-resolution approach for sea ice motion estimation

NASA Astrophysics Data System (ADS)

Petrou, Zisis I.; Xian, Yang; Tian, YingLi

2018-04-01

Estimation of sea ice motion at fine scales is important for a number of regional and local level applications, including modeling of sea ice distribution, ocean-atmosphere and climate dynamics, as well as safe navigation and sea operations. In this study, we propose an optical flow and super-resolution approach to accurately estimate motion from remote sensing images at a higher spatial resolution than the original data. First, an external example learning-based super-resolution method is applied on the original images to generate higher resolution versions. Then, an optical flow approach is applied on the higher resolution images, identifying sparse correspondences and interpolating them to extract a dense motion vector field with continuous values and subpixel accuracies. Our proposed approach is successfully evaluated on passive microwave, optical, and Synthetic Aperture Radar data, proving appropriate for multi-sensor applications and different spatial resolutions. The approach estimates motion with similar or higher accuracy than the original data, while increasing the spatial resolution of up to eight times. In addition, the adopted optical flow component outperforms a state-of-the-art pattern matching method. Overall, the proposed approach results in accurate motion vectors with unprecedented spatial resolutions of up to 1.5 km for passive microwave data covering the entire Arctic and 20 m for radar data, and proves promising for numerous scientific and operational applications.

Shoulder tenotomies to improve passive motion and relieve pain in patients with spastic hemiplegia after upper motor neuron injury.

PubMed

Namdari, Surena; Alosh, Hassan; Baldwin, Keith; Mehta, Samir; Keenan, Mary Ann

2011-07-01

Shoulder adduction and internal rotation contractures commonly develop in patients with spastic hemiplegia after upper motor neuron (UMN) injury. Contractures are often painful, macerate skin, and impair axillary hygiene. We hypothesize that shoulder tenotomies are an effective means of pain relief and passive motion restoration in patients without active upper extremity motor function. A consecutive series of 36 adults (10 men, 26 women) with spastic hemiplegia from UMN injury, shoulder adduction, and internal rotation contractures, and no active movement, who underwent shoulder tenotomies of the pectoralis major, latissimus dorsi, teres major, and subscapularis were evaluated. Patients were an average age of 52.2 years. Pain, passive motion, and satisfaction were considered preoperatively and postoperatively. Average follow-up was 14.3 months. Preoperatively, all patients had limited passive motion that interfered with passive functions. Nineteen patients had pain. After surgery, passive extension, flexion, abduction, and external rotation improved from 50%, 27%, 27%, and 1% to 85%, 70%, 66%, and 56%, respectively, compared with the normal contralateral side (P < .001). All patients with preoperative pain had improved pain relief at follow-up, with 18 (95%) being pain-free. Thirty-five (97%) were satisfied with the outcome of surgery, and all patients reported improved axillary hygiene and skin care. Age, gender, etiology, and chronicity of UMN injury were not associated with improvement in motion. We observed improvements in passive ROM and high patient satisfaction with surgery at early follow-up. Patients who had pain with passive motion preoperatively had significant improvements in pain after shoulder tenotomy. Shoulder tenotomy to relieve spastic contractures resulting from UMN injury can be an effective means of pain relief and improved passive range of motion in patients without active motor function. Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Influence of Passive Joint Stiffness on Proprioceptive Acuity in Individuals With Functional Instability of the Ankle.

PubMed

Marinho, Hellen Veloso Rocha; Amaral, Giovanna Mendes; de Souza Moreira, Bruno; Araújo, Vanessa Lara; Souza, Thales Rezende; Ocarino, Juliana Melo; da Fonseca, Sérgio Teixeira

2017-12-01

Study Design Controlled laboratory study, cross-sectional. Background Deficits in ankle proprioceptive acuity have been reported in persons with functional instability of the ankle. Passive stiffness has been proposed as a possible mechanism underlying proprioceptive acuity. Objective To compare proprioceptive acuity and passive ankle stiffness in persons with and without functional ankle instability, and to assess the influence of passive joint stiffness on proprioceptive acuity in persons with functional ankle instability. Methods A sample of 18 subjects with and 18 without complaints of functional ankle instability following lateral ankle sprain participated. An isokinetic dynamometer was used to compare motion perception threshold, passive position sense, and passive ankle stiffness between groups. To evaluate the influence of passive stiffness on proprioceptive acuity, individuals in the lateral functional ankle instability group were divided into 2 subgroups: "high" and "low" passive ankle stiffness. Results The functional ankle instability group exhibited increased motion perception threshold when compared with the corresponding limb of the control group. Between-group differences were not found for passive position sense and passive ankle stiffness. Those in the functional ankle instability group with higher passive ankle stiffness had smaller motion perception thresholds than those with lower passive ankle stiffness. Conclusion Unlike motion perception threshold, passive position sense is not affected by the presence of functional ankle instability. Passive ankle stiffness appears to influence proprioceptive acuity in persons with functional ankle instability. J Orthop Sports Phys Ther 2017;47(12):899-905. Epub 7 Oct 2017. doi:10.2519/jospt.2017.7030.

Effectiveness of prolonged use of continuous passive motion (CPM) as an adjunct to physiotherapy following total knee arthroplasty: design of a randomised controlled trial [ISRCTN85759656].

PubMed

Lenssen, Anton F; Crijns, Yvonne H F; Waltjé, Eddie M H; Roox, George M; van Steyn, Mike J A; Geesink, Ruud J T; van den Brandt, Piet A; de Bie, Rob A

2006-02-23

Adequate and intensive rehabilitation is an important requirement for successful Total Knee Arthroplasty. The primary focus of early rehabilitation is ambulation of patients and regaining range of motion in the knee. Although research suggests that Continuous Passive Motion should be implemented in the first rehabilitation phase following surgery, there is substantial debate about the duration of each session and the total period of CPM application and. A Cochrane review on this topic concluded that short-term use of CPM leads to greater short-term range of motion. It also suggested, however, that future research should concentrate on the treatment period during which CPM should be administered. In a randomised controlled trial we intend to investigate the efficacy of prolonged use of a continuous passive motion (CPM) device in the home situation as an adjunct to standardised physical therapy. The experimental treatment is compared to standardised physical therapy, in patients with osteoarthritis of the knee undergoing Total Knee Arthroplasty (TKA). Efficacy will be assessed in terms of faster improvements in range of motion and functional recovery. Seventy patients with knee osteoarthritis undergoing TKA and experiencing early postoperative flexion impairment (less than 80 degrees of knee flexion at the time of discharge) will be randomised over two treatment groups, a usual care group and an experimental group. The experimental group will receive CPM + physiotherapy for 17 consecutive days after surgery, whereas the usual care group will receive the same treatment during the in-hospital phase (i.e. about four days), followed by physical therapy alone (usual care) in the first two weeks after hospital discharge. From 18 days to three months after discharge, both groups will receive standardised PT. The primary focus of rehabilitation will be functional recovery (e.g. ambulation) and regaining range of motion (ROM) in the knee. Because restricted knee ROM affects functional activities, knee ROM and knee function are regarded as the primary indicators of successful TKA. Potential effects of the intervention under study include rapid return of knee flexion accompanied by earlier return to functional activities of daily life. If patients benefit significantly from prolonged CPM use, this treatment should be added to the standard PT treatment at home. We expect the additional home CPM programme to be more effective than the usual physiotherapy programme, resulting in a difference in ROM of at least 5 degrees , 17 days after surgery. This clinically important difference, with a possible flexion ROM of about 100 degrees , is expected to lead to better functioning in activities of daily life, like walking, and earlier ability to cycle. These advantages should result in earlier and increasing independence.

Effectiveness of prolonged use of continuous passive motion (CPM) as an adjunct to physiotherapy following total knee arthroplasty: Design of a randomised controlled trial [ISRCTN85759656

PubMed Central

Lenssen, Anton F; Crijns, Yvonne HF; Waltjé, Eddie MH; Roox, George M; van Steyn, Mike JA; Geesink, Ruud JT; van den Brandt, Piet A; de Bie, Rob A

2006-01-01

Background Adequate and intensive rehabilitation is an important requirement for successful Total Knee Arthroplasty. The primary focus of early rehabilitation is ambulation of patients and regaining range of motion in the knee. Although research suggests that Continuous Passive Motion should be implemented in the first rehabilitation phase following surgery, there is substantial debate about the duration of each session and the total period of CPM application and. A Cochrane review on this topic concluded that short-term use of CPM leads to greater short-term range of motion. It also suggested, however, that future research should concentrate on the treatment period during which CPM should be administered. Methods In a randomised controlled trial we intend to investigate the efficacy of prolonged use of a continuous passive motion (CPM) device in the home situation as an adjunct to standardised physical therapy. The experimental treatment is compared to standardised physical therapy, in patients with osteoarthritis of the knee undergoing Total Knee Arthroplasty (TKA). Efficacy will be assessed in terms of faster improvements in range of motion and functional recovery. Seventy patients with knee osteoarthritis undergoing TKA and experiencing early postoperative flexion impairment (less than 80° of knee flexion at the time of discharge) will be randomised over two treatment groups, a usual care group and an experimental group The experimental group will receive CPM + physiotherapy for 17 consecutive days after surgery, whereas the usual care group will receive the same treatment during the in-hospital phase (i.e. about four days), followed by physical therapy alone (usual care) in the first two weeks after hospital discharge. From 18 days to three months after discharge, both groups will receive standardised PT. The primary focus of rehabilitation will be functional recovery (e.g. ambulation) and regaining range of motion (ROM) in the knee. Discussion Because restricted knee ROM affects functional activities, knee ROM and knee function are regarded as the primary indicators of successful TKA. Potential effects of the intervention under study include rapid return of knee flexion accompanied by earlier return to functional activities of daily life. If patients benefit significantly from prolonged CPM use, this treatment should be added to the standard PT treatment at home. We expect the additional home CPM programme to be more effective than the usual physiotherapy programme, resulting in a difference in ROM of at least 5°, 17 days after surgery. This clinically important difference, with a possible flexion ROM of about 100°, is expected to lead to better functioning in activities of daily life, like walking, and earlier ability to cycle. These advantages should result in earlier and increasing independence. PMID:16504087

Effect of body mass index on knee function outcomes following continuous passive motion in patients with osteoarthritis after total knee replacement: a retrospective study.

PubMed

Liao, C-D; Huang, Y-C; Chiu, Y-S; Liou, T-H

2017-09-01

Obesity may influence postoperative rehabilitation outcomes after total knee replacement (TKR). The aim of this study was to evaluate the effects of body mass index (BMI) on the progression of inpatient rehabilitation using continuous passive motion (CPM) and its treatment outcomes. A retrospective study was conducted in a rehabilitation centre. In total, 354 patients undergoing primary TKR were enrolled through medical chart review. All patients commenced the CPM programme immediately after surgery and continued until hospital discharge. Knee flexion, pain score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function score. Patients were divided into five BMI groups: normal weight (n=59), overweight (n=95), Class I obesity (n=90), Class II obesity (n=82) and Class III obesity (n=28). All outcome measures were recorded at admission; daily during the inpatient stay; at discharge; and at 1-, 3- and 6-month follow-up assessments. During CPM exercises, obese patients had a smaller initial flexion angle (P<0.001) and a smaller daily increment in the CPM motion arc (P<0.001) compared with patients of normal weight. Severe obesity was associated with poor knee flexion [adjusted odds ratio (aOR) 11.9, 95% confidence interval (CI) 3.49 to 40.94, P<0.001] and WOMAC physical function score (aOR 5.09, 95% CI 1.62 to 16.03, P=0.005) at 6-month follow-up. Obesity had a negative effect on progress during the CPM protocol, which commenced immediately after surgery and continued until discharge. Obesity was also associated with poorer self-reported function at 6-month follow-up. Copyright © 2016 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

[Burn scars: rehabilitation and skin care].

PubMed

Rochet, Jean-Michel; Zaoui, Affif

2002-12-15

Burn rehabilitation main goal is to minimize the consequences of hypertrophic scars and concomitant contractures. The treatment principles rely on the association of joint posture, continuous pressure completed with range of motion to prevent joint fusion (which happens to adults but not to children). Throughout the different treatment phases and wound evolution, reassessment is necessary to review rehabilitation goals and activities. During the acute phase the alternance of positioning is prioritized in order to keep the affected extremities in antideformity position using splint or other devices. At the rehabilitation phase, treatment is focussed on active/passive range of motion (skin posture) strengthening exercises and use of dynamic splint is introduced to correct contractures. After their discharge home, patients benefit from outpatient rehab until scar maturation (approximately 18 months). The treatment consists mainly on active/passive range of motion, scar massage, strengthening exercise and endurance retraining. Also modalities (such as thermal bath and high pressure water spray) are used to address itching problems and for scar softening. Finally, reconstructive surgery can be performed to correct excessive scarring or joint contracture for better functional or cosmetic outcome.

Integration of Canal and Otolith Inputs by Central Vestibular Neurons Is Subadditive for Both Active and Passive Self-Motion: Implication for Perception

PubMed Central

Carriot, Jerome; Jamali, Mohsen; Brooks, Jessica X.

2015-01-01

Traditionally, the neural encoding of vestibular information is studied by applying either passive rotations or translations in isolation. However, natural vestibular stimuli are typically more complex. During everyday life, our self-motion is generally not restricted to one dimension, but rather comprises both rotational and translational motion that will simultaneously stimulate receptors in the semicircular canals and otoliths. In addition, natural self-motion is the result of self-generated and externally generated movements. However, to date, it remains unknown how information about rotational and translational components of self-motion is integrated by vestibular pathways during active and/or passive motion. Accordingly, here, we compared the responses of neurons at the first central stage of vestibular processing to rotation, translation, and combined motion. Recordings were made in alert macaques from neurons in the vestibular nuclei involved in postural control and self-motion perception. In response to passive stimulation, neurons did not combine canal and otolith afferent information linearly. Instead, inputs were subadditively integrated with a weighting that was frequency dependent. Although canal inputs were more heavily weighted at low frequencies, the weighting of otolith input increased with frequency. In response to active stimulation, neuronal modulation was significantly attenuated (∼70%) relative to passive stimulation for rotations and translations and even more profoundly attenuated for combined motion due to subadditive input integration. Together, these findings provide insights into neural computations underlying the integration of semicircular canal and otolith inputs required for accurate posture and motor control, as well as perceptual stability, during everyday life. PMID:25716854

A unified internal model theory to resolve the paradox of active versus passive self-motion sensation

PubMed Central

Angelaki, Dora E

2017-01-01

Brainstem and cerebellar neurons implement an internal model to accurately estimate self-motion during externally generated (‘passive’) movements. However, these neurons show reduced responses during self-generated (‘active’) movements, indicating that predicted sensory consequences of motor commands cancel sensory signals. Remarkably, the computational processes underlying sensory prediction during active motion and their relationship to internal model computations during passive movements remain unknown. We construct a Kalman filter that incorporates motor commands into a previously established model of optimal passive self-motion estimation. The simulated sensory error and feedback signals match experimentally measured neuronal responses during active and passive head and trunk rotations and translations. We conclude that a single sensory internal model can combine motor commands with vestibular and proprioceptive signals optimally. Thus, although neurons carrying sensory prediction error or feedback signals show attenuated modulation, the sensory cues and internal model are both engaged and critically important for accurate self-motion estimation during active head movements. PMID:29043978

Smart security system for Indian rail wagons using IOT

NASA Astrophysics Data System (ADS)

Bhanuteja, S.; Shilpi, S.; Pragna, K.; Arun, M.

2017-11-01

The objective of this project is to create a Security System for the goods that are carried in open top freight trains. The most efficient way to secure anything from thieves is to have a continuous observation. So for continuous observation of the open top freight train, Camera module2 has been used. Passive Infrared Sensor (PIR) 1 has been used to detect the motion or to sense movement of people, animals, or any object. So whenever a motion is detected by the PIR sensor, the Camera takes a picture of that particular instance. That picture will be send to the Raspberry PI which does Skin Detection Algorithm and specifies whether that motion was created by a human or not. If a human makes it, then that picture will send to the drop box. Any Official can have a look at the same. The existing system has a CCTV installed at various critical locations like bridges, railway stations etc. but they does not provide a continuous observation. This paper describes about the Security System that provides continuous observation for open top freight trains so that goods can be carried safely to its destination.

The Effect of Passive Movement for Paretic Ankle-Foot and Brain Activity in Post-Stroke Patients.

PubMed

Vér, Csilla; Emri, Miklós; Spisák, Tamás; Berényi, Ervin; Kovács, Kázmér; Katona, Péter; Balkay, László; Menyhárt, László; Kardos, László; Csiba, László

2016-01-01

This study aims at investigating the short-term efficacy of the continuous passive motion (CPM) device developed for the therapy of ankle-foot paresis and to investigate by fMRI the blood oxygen level-dependent responses (BOLD) during ankle passive movement (PM). Sixty-four stroke patients were investigated. Patients were assigned into 2 groups: 49 patients received both 15 min manual and 30 min device therapy (M + D), while the other group (n = 15) received only 15 min manual therapy (M). A third group of stroke patients (n = 12) was investigated by fMRI before and immediately after 30 min CPM device therapy. There was no direct relation between the fMRI group and the other 2 groups. All subjects were assessed using the Modified Ashworth Scale (MAS) and a goniometer. Mean MAS decreased, the ankle's mean plantar flexion and dorsiflexion passive range of motion (PROM) increased and the equinovalgus improved significantly in the M + D group. In the fMRI group, the PM of the paretic ankle increased BOLD responses; this was observed in the contralateral pre- and postcentral gyrus, superior temporal gyrus, central opercular cortex, and in the ipsilateral postcentral gyrus, frontal operculum cortex and cerebellum. Manual therapy with CPM device therapy improved the ankle PROM, equinovalgus and severity of spasticity. The ankle PM increased ipsi- and contralateral cortical activation. © 2016 S. Karger AG, Basel.

PSD Camera Based Position and Posture Control of Redundant Robot Considering Contact Motion

NASA Astrophysics Data System (ADS)

Oda, Naoki; Kotani, Kentaro

The paper describes a position and posture controller design based on the absolute position by external PSD vision sensor for redundant robot manipulator. The redundancy enables a potential capability to avoid obstacle while continuing given end-effector jobs under contact with middle link of manipulator. Under contact motion, the deformation due to joint torsion obtained by comparing internal and external position sensor, is actively suppressed by internal/external position hybrid controller. The selection matrix of hybrid loop is given by the function of the deformation. And the detected deformation is also utilized in the compliant motion controller for passive obstacle avoidance. The validity of the proposed method is verified by several experimental results of 3link planar redundant manipulator.

Passive stability and actuation of micro aerial vehicles

NASA Astrophysics Data System (ADS)

Piccoli, Matthew

Micro Aerial Vehicles (MAVs) have increased in popularity in recent years. The most common platform, the quadrotor, has surpassed other MAVs like traditional helicopters and ornithopters in popularity mainly due to their simplicity. Yet the quadrotor design is a century old and was intended to carry people. We set out to design a MAV that is designed specifically to be a MAV, i.e. a vehicle not intended to carry humans as a payload. With this constraint lifted the vehicle can continuously rotate, which would dizzy a human, can sustain larger forces, which would damage a human, or can take advantage of scaling properties, where it may not work at human scale. Furthermore, we aim for simplicity by removing vehicle controllers and reducing the number of actuators, such that the vehicle can be made cost effective, if not disposable. We begin by studying general equations of motion for hovering MAVs. We search for vehicle configurations that exhibit passive stability, allowing the MAV to operate without a controller or actuators to apply control, ideally a single actuator. The analysis suggests two distinct types of passively stabilized MAVs and we create test vehicles for both. With simple hovering achieved, we concentrate on controlled motion with an emphasis on doing so without adding actuators. We find we can attain three degree of freedom control using separation of time scales with our actuator via low frequency for control in the vertical direction and high frequency for control in the horizontal plane. We explore techniques for achieving high frequency actuator control, which also allow the compensation of motor defects, specifically cogging torque. We combine passive stability with the motion control into two vehicles, UNO and Piccolissimo. UNO, the Underactuated-propeller Naturally-stabilized One-motor vehicle, demonstrates the capabilities of simple vehicles by performing maneuvers like conventional quadrotors. Piccolissimo, Italian for very little, demonstrates the merits of passive stability and single actuator control by being the smallest, self-powered, controllable MAV.

Hamstring Stiffness Returns More Rapidly After Static Stretching Than Range of Motion, Stretch Tolerance, and Isometric Peak Torque.

PubMed

Hatano, Genki; Suzuki, Shigeyuki; Matsuo, Shingo; Kataura, Satoshi; Yokoi, Kazuaki; Fukaya, Taizan; Fujiwara, Mitsuhiro; Asai, Yuji; Iwata, Masahiro

2017-12-18

Hamstring injuries are common, and lack of hamstring flexibility may predispose to injury. Static stretching increases range of motion (ROM) but also results in reduced muscle strength after stretching. The effects of stretching on the hamstring muscles and the duration of these effects remain unclear. To determine the effects of static stretching on the hamstrings and the duration of these effects. Randomized crossover study. University laboratory. Twenty-four healthy volunteers. We measured the torque-angle relationship (ROM, passive torque (PT) at the onset of pain, and passive stiffness) and isometric muscle force using an isokinetic dynamometer. After a 60-minute rest, the ROM of the dynamometer was set at maximum tolerable intensity; this position was maintained for 300 seconds while static passive torque (SPT) was measured continuously. We remeasured the torque-angle relationship and isometric muscle force after rest periods of 10, 20, and 30 minutes. Change in SPT during stretching; changes in ROM, PT at the onset of pain, passive stiffness, and isometric muscle force before stretching compared with 10, 20, and 30 minutes after stretching. SPT decreased significantly during stretching. Passive stiffness decreased significantly 10 and 20 minutes after stretching, but there was no significant pre- vs. post-stretching difference after 30 minutes. PT at the onset of pain and ROM increased significantly after stretching at all rest intervals, while isometric muscle force decreased significantly after all rest intervals. The effect of static stretching on passive stiffness of the hamstrings was not maintained as long as the changes in ROM, stretch tolerance, and isometric muscle force. Therefore, frequent stretching is necessary to improve the viscoelasticity of the muscle-tendon unit. Muscle force was decreased for 30 minutes after stretching; this should be considered prior to activities requiring maximal muscle strength.

Feasibility of Using Low-Cost Motion Capture for Automated Screening of Shoulder Motion Limitation after Breast Cancer Surgery.

PubMed

Gritsenko, Valeriya; Dailey, Eric; Kyle, Nicholas; Taylor, Matt; Whittacre, Sean; Swisher, Anne K

2015-01-01

To determine if a low-cost, automated motion analysis system using Microsoft Kinect could accurately measure shoulder motion and detect motion impairments in women following breast cancer surgery. Descriptive study of motion measured via 2 methods. Academic cancer center oncology clinic. 20 women (mean age = 60 yrs) were assessed for active and passive shoulder motions during a routine post-operative clinic visit (mean = 18 days after surgery) following mastectomy (n = 4) or lumpectomy (n = 16) for breast cancer. Participants performed 3 repetitions of active and passive shoulder motions on the side of the breast surgery. Arm motion was recorded using motion capture by Kinect for Windows sensor and on video. Goniometric values were determined from video recordings, while motion capture data were transformed to joint angles using 2 methods (body angle and projection angle). Correlation of motion capture with goniometry and detection of motion limitation. Active shoulder motion measured with low-cost motion capture agreed well with goniometry (r = 0.70-0.80), while passive shoulder motion measurements did not correlate well. Using motion capture, it was possible to reliably identify participants whose range of shoulder motion was reduced by 40% or more. Low-cost, automated motion analysis may be acceptable to screen for moderate to severe motion impairments in active shoulder motion. Automatic detection of motion limitation may allow quick screening to be performed in an oncologist's office and trigger timely referrals for rehabilitation.

Design for active and passive flutter suppression and gust alleviation. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Karpel, M.

1981-01-01

Analytical design techniques for active and passive control of aeroelastic systems are based on a rational approximation of the unsteady aerodynamic loads in the entire Laplace domain, which yields matrix equations of motion with constant coefficients. Some existing schemes are reviewed, the matrix Pade approximant is modified, and a technique which yields a minimal number of augmented states for a desired accuracy is presented. The state-space aeroelastic model is used to design an active control system for simultaneous flutter suppression and gust alleviation. The design target is for a continuous controller which transfers some measurements taken on the vehicle to a control command applied to a control surface. Structural modifications are formulated in a way which enables the treatment of passive flutter suppression system with the same procedures by which active control systems are designed.

Passive damping in EDS maglev systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rote, D. M.

2002-05-03

There continues to be strong interest in the subjects of damping and drag forces associated with electrodynamic suspension (EDS) systems. While electromagnetic drag forces resist the forward motion of a vehicle and therefore consume energy, damping forces control, at least in part, the response of the vehicle to disturbances. Ideally, one would like to reduce the drag forces as much as possible while retaining adequate damping forces to insure dynamic stability and satisfactory ride quality. These two goals turn out to be difficult to achieve in practice. It is well known that maglev systems tend to be intrinsically under damped.more » Consequently it is often necessary in a practical system design to enhance the damping passively or actively. For reasons of cost and simplicity, it is desirable to rely as much as possible on passive damping mechanisms. In this paper, rough estimates are made of the passive damping and drag forces caused by various mechanisms in EDS systems. No attention will be given to active control systems or secondary suspension systems which are obvious ways to augment passive damping mechanisms if the latter prove to be inadequate.« less

Passive versus active stretching of hip flexor muscles in subjects with limited hip extension: a randomized clinical trial.

PubMed

Winters, Michael V; Blake, Charles G; Trost, Jennifer S; Marcello-Brinker, Toni B; Lowe, Lynne M; Garber, Matthew B; Wainner, Robert S

2004-09-01

Active stretching is purported to stretch the shortened muscle and simultaneously strengthen the antagonist muscle. The purpose of this study was to determine whether active and passive stretching results in a difference between groups at improving hip extension range of motion in patients with hip flexor muscle tightness. Thirty-three patients with low back pain and lower-extremity injuries who showed decreased range of motion, presumably due to hip flexor muscle tightness, completed the study. The subjects, who had a mean age of 23.6 years (SD = 5.3, range = 18-25), were randomly assigned to either an active home stretching group or a passive home stretching group. Hip extension range of motion was measured with the subjects in the modified Thomas test position at baseline and 3 and 6 weeks after the start of the study. Range of motion in both groups improved over time, but there were no differences between groups. The results indicate that passive and active stretching are equally effective for increasing range of motion, presumably due to increased flexibility of tight hip flexor muscles. Whether the 2 methods equally improve flexibility of other muscle groups or whether active stretching improves the function of the antagonist muscles is not known. Active and passive stretching both appeared to increase the flexibility of tight hip flexor muscles in patients with musculoskeletal impairments.

Advanced Demonstration of Motion Correction for Ship-to-Ship Passive Inspections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziock, Klaus-Peter; Boehnen, Chris Bensing; Ernst, Joseph

2013-09-30

Passive radiation detection is a key tool for detecting illicit nuclear materials. In maritime applications it is most effective against small vessels where attenuation is of less concern. Passive imaging provides: discrimination between localized (threat) and distributed (non-threat) sources, removal of background fluctuations due to nearby shorelines and structures, source localization to an individual craft in crowded waters, and background subtracted spectra. Unfortunately, imaging methods cannot be easily applied in ship-to-ship inspections because relative motion of the vessels blurs the results over many pixels, significantly reducing sensitivity. This is particularly true for the smaller water craft where passive inspections aremore » most valuable. In this project we performed tests and improved the performance of an instrument (developed earlier under, “Motion Correction for Ship-to-Ship Passive Inspections”) that uses automated tracking of a target vessel in visible-light images to generate a 3D radiation map of the target vessel from data obtained using a gamma-ray imager.« less

Deficits in Glenohumeral Passive Range of Motion Increase Risk of Shoulder Injury in Professional Baseball Pitchers: A Prospective Study.

PubMed

Wilk, Kevin E; Macrina, Leonard C; Fleisig, Glenn S; Aune, Kyle T; Porterfield, Ron A; Harker, Paul; Evans, Timothy J; Andrews, James R

2015-10-01

Shoulder injuries from repetitive baseball pitching continue to be a serious, common problem. To determine whether passive range of motion of the glenohumeral joint was predictive of shoulder injury or shoulder surgery in professional baseball pitchers. Cohort study; Level of evidence, 2. Passive range of motion of the glenohumeral joint was assessed with a bubble goniometer during spring training for all major and minor league pitchers of a single professional baseball organization over a period of 8 successive seasons (2005-2012). Investigators performed a total of 505 examinations on 296 professional pitchers. Glenohumeral external and internal rotation was assessed with the pitcher supine and the arm abducted to 90° in the scapular plane with the scapula stabilized anteriorly at the coracoid process. Total rotation was defined as the sum of internal and external glenohumeral rotation. Passive shoulder flexion was measured with the pitcher supine and the lateral border of the scapula manually stabilized. After examination, shoulder injuries and injury durations were recorded by each pitcher's respective baseball organization and reported to the league as an injury transaction as each player was placed on the disabled list. Highly significant side-to-side differences were noted within subjects for each range of motion measurement. There were 75 shoulder injuries and 20 surgeries recorded among 51 pitchers, resulting in 5570 total days on the disabled list. Glenohumeral internal rotation deficit, total rotation deficit, and flexion deficit were not significantly related to shoulder injury or surgery. Pitchers with insufficient external rotation (<5° greater external rotation in the throwing shoulder) were 2.2 times more likely to be placed on the disabled list for a shoulder injury (P = .014; 95% CI, 1.2-4.1) and were 4.0 times more likely to require shoulder surgery (P = .009; 95% CI, 1.5-12.6). Insufficient shoulder external rotation on the throwing side increased the likelihood of shoulder injury and shoulder surgery. Sports medicine clinicians should be aware of these findings and develop a preventive plan that addresses this study's findings to reduce pitchers' risk of shoulder injury and surgery. © 2015 The Author(s).

Multimodal Integration of Self-Motion Cues in the Vestibular System: Active versus Passive Translations

PubMed Central

Carriot, Jerome; Brooks, Jessica X.

2013-01-01

The ability to keep track of where we are going as we navigate through our environment requires knowledge of our ongoing location and orientation. In response to passively applied motion, the otolith organs of the vestibular system encode changes in the velocity and direction of linear self-motion (i.e., heading). When self-motion is voluntarily generated, proprioceptive and motor efference copy information is also available to contribute to the brain's internal representation of current heading direction and speed. However to date, how the brain integrates these extra-vestibular cues with otolith signals during active linear self-motion remains unknown. Here, to address this question, we compared the responses of macaque vestibular neurons during active and passive translations. Single-unit recordings were made from a subgroup of neurons at the first central stage of sensory processing in the vestibular pathways involved in postural control and the computation of self-motion perception. Neurons responded far less robustly to otolith stimulation during self-generated than passive head translations. Yet, the mechanism underlying the marked cancellation of otolith signals did not affect other characteristics of neuronal responses (i.e., baseline firing rate, tuning ratio, orientation of maximal sensitivity vector). Transiently applied perturbations during active motion further established that an otolith cancellation signal was only gated in conditions where proprioceptive sensory feedback matched the motor-based expectation. Together our results have important implications for understanding the brain's ability to ensure accurate postural and motor control, as well as perceptual stability, during active self-motion. PMID:24336720

A Null Space Control of Two Wheels Driven Mobile Manipulator Using Passivity Theory

NASA Astrophysics Data System (ADS)

Shibata, Tsuyoshi; Murakami, Toshiyuki

This paper describes a control strategy of null space motion of a two wheels driven mobile manipulator. Recently, robot is utilized in various industrial fields and it is preferable for the robot manipulator to have multiple degrees of freedom motion. Several studies of kinematics for null space motion have been proposed. However stability analysis of null space motion is not enough. Furthermore, these approaches apply to stable systems, but they do not apply unstable systems. Then, in this research, base of manipulator equips with two wheels driven mobile robot. This robot is called two wheels driven mobile manipulator, which becomes unstable system. In the proposed approach, a control design of null space uses passivity based stabilizing. A proposed controller is decided so that closed-loop system of robot dynamics satisfies passivity. This is passivity based control. Then, control strategy is that stabilizing of the robot system applies to work space observer based approach and null space control while keeping end-effector position. The validity of the proposed approach is verified by simulations and experiments of two wheels driven mobile manipulator.

Performance of active and passive control of an airfoil using CPFD

NASA Astrophysics Data System (ADS)

Asselin, Daniel; Young, Jay; Williamson, C. H. K.

2016-11-01

Birds and fish employ flapping motions of their wings and fins in order to produce thrust and maneuver in flight and underwater. There is considerable interest in designing aerial and submersible systems that mimic these motions for the purposes of surveillance, environmental monitoring, and search and rescue, among other applications. Flapping motions are typically composed of combined pitch and heave and can provide good thrust and efficiency (Read, et al. 2003). In this study, we examine the performance of an airfoil actuated only in the heave direction. Using a cyber-physical fluid dynamics system (Mackowski & Williamson 2011, 2015, 2016), we simulate the presence of a torsion spring to enable the airfoil to undergo a passively controlled pitching motion. The addition of passive pitching combined with active heaving ("Active-Passive" or AP) provides significantly improved thrust and efficiency compared with heaving alone. In many cases, values of thrust and efficiency are comparable to or better than those obtained with two actively controlled degrees of freedom ("Active-Active" or AA). By using carefully-designed passive dynamics in the pitch direction, we can eliminate one of the two actuators, saving cost, complexity, and weight, while maintaining or improving performance. This work was supported by the Air Force Office of Scientific Research Grant No. FA9550-15-1-0243, monitored by Dr. Douglas Smith.

Manual calf massage and passive ankle motion reduce the incidence of deep vein thromboembolism after total hip arthroplasty.

PubMed

Imai, Norio; Ito, Tomoyuki; Suda, Ken; Miyasaka, Dai; Endo, Naoto

2017-07-01

Venous thromboembolism is one of the general complications following total hip arthroplasty, wherein various preventive treatments have been recommended. Several studies reported that venous thromboembolism incidence after total hip arthroplasty was similar in patients who were administered prophylaxis with a conventional mechanical procedure alone, and those who were administered pharmacological anticoagulation therapy. Therefore, the optimum methods of prophylaxis are still controversial. The purpose of this study was to investigate whether manual calf massage and passive ankle motion could lower the risk for venous thromboembolism after total hip arthroplasty. We retrospectively reviewed the data of 126 consecutive patients undergoing elective primary unilateral total hip arthroplasty wherein manual calf massage and passive ankle motion were performed after the surgery at our hospitals between January and October 2014. The 138 patients of the control group underwent total hip arthroplasty using the same surgical approach and pre- and postoperative protocols without this mechanical prophylaxis between January and December 2013. This mechanical prophylaxis was performed simultaneously 30 times during approximately 10 s; these procedures were repeated thrice immediately after total hip arthroplasty. Duplex ultrasonography was performed to observe the veins of both legs in all the patients on postoperative day 7. The incidence of deep vein thrombosis was 6.52% and 0.79% in the control and manual calf massage and passive ankle motion groups, respectively. The odds ratio for the manual calf massage and passive ankle motion groups was 8.72. Performing this mechanical prophylaxis reduced the incidence of venous thromboembolism after total hip arthroplasty. This mechanical prophylaxis is not only simple and easy, but is also safe and inexpensive. We therefore recommend that manual calf massage and passive ankle motion be performed in patients who will undergo total hip arthroplasty, if deep vein thrombosis does not exist before the surgery. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Prospective randomized study of arthroscopic rotator cuff repair using an early versus delayed postoperative physical therapy protocol.

PubMed

Cuff, Derek J; Pupello, Derek R

2012-11-01

This study evaluated patient outcomes and rotator cuff healing after arthroscopic rotator cuff repair using a postoperative physical therapy protocol with early passive motion compared with a delayed protocol that limited early passive motion. The study enrolled 68 patients (average age, 63.2 years) who met inclusion criteria. All patients had a full-thickness crescent-shaped tear of the supraspinatus that was repaired using a transosseous equivalent suture-bridge technique along with subacromial decompression. In the early group, 33 patients were randomized to passive elevation and rotation that began at postoperative day 2. In the delayed group, 35 patients began the same protocol at 6 weeks. Patients were monitored clinically for a minimum of 12 months, and rotator cuff healing was assessed using ultrasound imaging. Both groups had similar improvements in preoperative to postoperative American Shoulder and Elbow Surgeons scores (early group: 43.9 to 91.9, P < .0001; delayed group: 41.0 to 92.8, P < .0001) and Simple Shoulder Test scores (early group: 5.5 to 11.1, P < .0001; delayed group: 5.1 to 11.1, P < .0001). There were no significant differences in patient satisfaction, rotator cuff healing, or range of motion between the early and delayed groups. Patients in the early group and delayed group both demonstrated very similar outcomes and range of motion at 1 year. There was a slightly higher rotator cuff healing rate in the delayed passive range of motion group compared with the early passive range of motion group (91% vs 85%). Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Static and Dynamic Water Motion-Induced Instability in Oxide Thin-Film Transistors and Its Suppression by Using Low-k Fluoropolymer Passivation.

PubMed

Choi, Seungbeom; Jo, Jeong-Wan; Kim, Jaeyoung; Song, Seungho; Kim, Jaekyun; Park, Sung Kyu; Kim, Yong-Hoon

2017-08-09

Here, we report static and dynamic water motion-induced instability in indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) and its effective suppression with the use of a simple, solution-processed low-k (ε ∼ 1.9) fluoroplastic resin (FPR) passivation layer. The liquid-contact electrification effect, in which an undesirable drain current modulation is induced by a dynamic motion of a charged liquid such as water, can cause a significant instability in IGZO TFTs. It was found that by adopting a thin (∼44 nm) FPR passivation layer for IGZO TFTs, the current modulation induced by the water-contact electrification was greatly reduced in both off- and on-states of the device. In addition, the FPR-passivated IGZO TFTs exhibited an excellent stability to static water exposure (a threshold voltage shift of +0.8 V upon 3600 s of water soaking), which is attributed to the hydrophobicity of the FPR passivation layer. Here, we discuss the origin of the current instability caused by the liquid-contact electrification as well as various static and dynamic stability tests for IGZO TFTs. On the basis of our findings, we believe that the use of a thin, solution-processed FPR passivation layer is effective in suppressing the static and dynamic water motion-induced instabilities, which may enable the realization of high-performance and environment-stable oxide TFTs for emerging wearable and skin-like electronics.

Understanding movement control in infants through the analysis of limb intersegmental dynamics.

PubMed

Schneider, K; Zernicke, R F; Ulrich, B D; Jensen, J L; Thelen, E

1990-12-01

One important component in the understanding of the control of limb movements is the way in which the central nervous system accounts for joint forces and torques that may be generated not only by muscle actions but by gravity and by passive reactions related to the movements of limb segments. In this study, we asked how the neuromotor system of young infants controls a range of active and passive forces to produce a stereotypic, nonintentional movement. We specifically analyzed limb intersegmental dynamics in spontaneous, cyclic leg movements (kicking) of varying intensity in supine 3-month-old human infants. Using inverse dynamics, we calculated the contributions of active (muscular) and passive (motion-dependent and gravitational) torque components at the hip, knee, and ankle joints from three-dimensional limb kinematics. To calculate joint torques, accurate estimates were needed of the limb's anthropometric parameters, which we determined using a model of the human body. Our analysis of limb intersegmental dynamics explicitly quantified the complex interplay of active and passive forces producing the simple, involuntary kicking movements commonly seen in 3-month-old infants. our results revealed that in nonvigorous kicks, hip joint reversal was the result of an extensor torque due to gravity, opposed by the combined flexor effect of the muscle torque and the total motion-dependent torque. The total motion-dependent torque increased as a hip flexor torque in more vigorous kicks; an extensor muscle torque was necessary to counteract the flexor influences of the total motion-dependent torque and, in the case of large ranges of motion, a flexor gravity torque as well. Thus, with changing passive torque influences due to motions of the linked segments, the muscle torques were adjusted to produce a net torque to reverse the kicking motion. As a consequence, despite considerable heterogeneity in the intensity, range of motion, coordination, and movement context of each kick, smooth trajectories resulted from the muscle torque, counteracting and complementing not only gravity but also the motion-dependent torques generated by movement of the linked segments.

Inertial navigation sensor integrated motion analysis for autonomous vehicle navigation

NASA Technical Reports Server (NTRS)

Roberts, Barry; Bhanu, Bir

1992-01-01

Recent work on INS integrated motion analysis is described. Results were obtained with a maximally passive system of obstacle detection (OD) for ground-based vehicles and rotorcraft. The OD approach involves motion analysis of imagery acquired by a passive sensor in the course of vehicle travel to generate range measurements to world points within the sensor FOV. INS data and scene analysis results are used to enhance interest point selection, the matching of the interest points, and the subsequent motion-based computations, tracking, and OD. The most important lesson learned from the research described here is that the incorporation of inertial data into the motion analysis program greatly improves the analysis and makes the process more robust.

RETRACTED ARTICLE: Clinical effectiveness of continuous passive motion (CPM) following femoroacetabular impingement surgery in adolescents.

PubMed

Hosalkar, Harish; Bomar, James D

2012-08-01

This study hypothesizes that the use of continuous passive motion (CPM) following open femoroacetabular impingement (FAI) surgery in the adolescent population improves clinical outcomes in terms of the modified Harris hip score (mHHS). Twenty-nine symptomatic adolescent FAI patients were postoperatively divided into one of three groups; no CPM, two days of inpatient CPM, and two weeks of CPM. mHHS was used preoperatively and postoperatively at six weeks, three months, six months, and nine months in all cases. Kruskal-Wallis (KW) analysis was performed to determine statistical differences in mHHS. mHHS was then re-evaluated using the Mann-Whitney test. There were no statistically significant differences in hip scores between the three groups preoperatively (p = 0.158). There were statistically significant differences (p < 0.001) in mHHS between the three groups at all postoperative time periods. The group that received two weeks of CPM had the best outcome scores. The results of this study suggest that postoperative CPM use following open hip preservation surgery for symptomatic FAI in adolescents improves clinical outcomes. These benefits seem to be related to the duration of CPM. Retrospective comparative study, Level III. Patients treated one way compared with patients treated another way at the same institution.

One-degree-of-freedom spherical model for the passive motion of the human ankle joint.

PubMed

Sancisi, Nicola; Baldisserri, Benedetta; Parenti-Castelli, Vincenzo; Belvedere, Claudio; Leardini, Alberto

2014-04-01

Mathematical modelling of mobility at the human ankle joint is essential for prosthetics and orthotic design. The scope of this study is to show that the ankle joint passive motion can be represented by a one-degree-of-freedom spherical motion. Moreover, this motion is modelled by a one-degree-of-freedom spherical parallel mechanism model, and the optimal pivot-point position is determined. Passive motion and anatomical data were taken from in vitro experiments in nine lower limb specimens. For each of these, a spherical mechanism, including the tibiofibular and talocalcaneal segments connected by a spherical pair and by the calcaneofibular and tibiocalcaneal ligament links, was defined from the corresponding experimental kinematics and geometry. An iterative procedure was used to optimize the geometry of the model, able to predict original experimental motion. The results of the simulations showed a good replication of the original natural motion, despite the numerous model assumptions and simplifications, with mean differences between experiments and predictions smaller than 1.3 mm (average 0.33 mm) for the three joint position components and smaller than 0.7° (average 0.32°) for the two out-of-sagittal plane rotations, once plotted versus the full flexion arc. The relevant pivot-point position after model optimization was found within the tibial mortise, but not exactly in a central location. The present combined experimental and modelling analysis of passive motion at the human ankle joint shows that a one degree-of-freedom spherical mechanism predicts well what is observed in real joints, although its computational complexity is comparable to the standard hinge joint model.

Reliability of shoulder internal rotation passive range of motion measurements in the supine versus sidelying position.

PubMed

Lunden, Jason B; Muffenbier, Mike; Giveans, M Russell; Cieminski, Cort J

2010-09-01

Clinical measurement, reliability. To compare intrarater and interrater reliability of shoulder internal rotation (IR) passive range of motion measurements utilizing a standard supine position and a sidelying position. Glenohumeral IR range of motion deficits are often noted in patients with shoulder pathology. Excellent intrarater reliability has been found when measuring this motion. However, interrater reliability has been reported as poor to fair. Some clinicians currently use a sidelying position for IR stretching with patients who have shoulder pathology. However, no objective data exist for IR passive range of motion measured in this sidelying position, either in terms of reliability or normative values. Seventy subjects (mean age, 36.8 years), with (n = 19) and without (n = 51) shoulder pathology, were included in this study. Shoulder IR passive range of motion of the dominant shoulder or involved shoulder was measured by 2 investigators in 2 positions: (1) a standard supine position, with the shoulder at 90 degrees of abduction, and (2) in sidelying on the tested side, with the shoulder flexed to 90 degrees . Intrarater reliability for supine measurements was good to excellent (ICC3,1 = 0.70-0.93) and for sidelying measurements was excellent (ICC3,1 = 0.94-0.98). Interrater reliability was fair to good for the supine measurement (ICC2,2 = 0.74-0.81) and good to excellent for the sidelying measurement (ICC2,2 = 0.88-0.96). The mean (range) value of the dominant shoulder sidelying IR passive range of motion was 40 degrees (11 degrees to 69 degrees ) for healthy subjects and 25 degrees (-16 degrees to 49 degrees) for subjects with shoulder pathology. For subjects with shoulder pathology, measurements of shoulder IR made in the sidelying position had superior intrarater and interrater reliability compared to those in the standard supine position.

Comparison of 2 Analgesia Modalities in Total Knee Replacement Surgery: Is There an Effect on Knee Function Rehabilitation?

PubMed

Zinkus, Janis; Mockutė, Lina; Gelmanas, Arūnas; Tamošiūnas, Ramūnas; Vertelis, Arūnas; Macas, Andrius

2017-06-20

BACKGROUND We compared the effects of continuous femoral nerve block (CFNB) and continuous intraarticular block (CIAB) on pain, functional recovery and adverse effects after total knee arthroplasty (TKA). MATERIAL AND METHODS We prospectively randomized 54 patients undergoing TKA into 2 groups: CFNB (Group F) and CIAB (Group I). Surgery was performed under spinal anesthesia. All patients received patient-controlled analgesia (PCA) with morphine, diclofenac, and acetaminophen for the first 72 h postoperatively. Pain was assessed with a visual analog scale (VAS), 48-h morphine consumption and 72-h local anesthetic dosage were recorded, motor blockade was assessed, maximum range of motion (ROM) was measured, and adverse effect profiles were recorded. RESULTS There was no significant difference in postoperative pain at rest, in passive motion, active motion, or active movement (2-min walk test (2MWT)) between study groups. Group I had less opioid usage in the first 24 h postoperatively (p<0.05). No significant difference was found between the groups in the postoperative local anesthetic dosage (p>0.05). Significantly lower scores of Bromage scale in Group I in 72 h after surgery (p<0.05) were found. Group I had superior passive maximum ROM in 1 month after surgery and superior active maximum ROM on day 7 and at 1 month after surgery (p<0.05). CONCLUSIONS Both CFNB and CIAB are effective postoperative analgesia methods after TKA. CIAB leads to lower postoperative opioid usage in the first 24 h, lower motor blockade in the first 72 h, and better knee function on day 7 and at 1 month after surgery.

Participation of primary motor cortex area 4a in complex sensory processing: 3.0-T fMRI study.

PubMed

Terumitsu, Makoto; Ikeda, Kotaro; Kwee, Ingrid L; Nakada, Tsutomu

2009-05-06

The precise movement of human fingers requires continuous and reciprocal interaction between motor and sensory systems. Similar to other primates, there is double representation of the digits and wrists within the human primary motor cortex (M1), which are generally referred to as area 4 anterior (M1-4a) and area 4 posterior (M1-4p). In this high-field (3.0 T) functional magnetic resonance imaging (fMRI) study, we hypothesized that M1-4p is more important for initiation of motion, whereas M1-4a is important for execution of a given motion involving more complex sensoriomotor interaction. We investigated M1-4a and M1-4p activation associated with two representative motor tasks, namely, finger tapping (voluntary motion, VM) and passive finger movement accomplished by continuous pressure (passive motor, PM), and two representative sensory stimulations, namely, simple stimulation of flutter vibration (simple sensory, SS), and complex stimulation by a row of pins moving either vertically or horizontally (complex sensory, CS). Both M1-4a and M1-4p were activated in both motor tasks, VM and PM. M1-4p was not activated by either of the two sensory tasks, whereas M1-4a was activated by CS but not by SS. Analysis of the center of gravities (COG) of the activated areas showed that VM and PM moved COG towards M1-4p and 3a. SS moved COG towards somatosensory cortex Brodmann areas 1, 2, and 3b, whereas CS towards M1-4a. The result clearly showed that M1-4a represents the area of secondary motor execution, which actively participates in CS processing.

Clinical outcomes and static and dynamic assessment of foot posture after lateral column lengthening procedure.

PubMed

Barske, Heather; Chimenti, Ruth; Tome, Josh; Martin, Elizabeth; Flemister, Adolph S; Houck, Jeff

2013-05-01

Lateral column lengthening (LCL) has been shown to radiographically restore the medial longitudinal arch. However, the impact of LCL on foot function during gait has not been reported using validated clinical outcomes and gait analysis. Thirteen patients with a stage II flatfoot who had undergone unilateral LCL surgery and 13 matched control subjects completed self-reported pain and functional scales as well as a clinical examination. A custom force transducer was used to establish the maximum passive range of motion of first metatarsal dorsiflexion at 40 N of force. Foot kinematic data were collected during gait using 3-dimensional motion analysis techniques. Radiographic correction of the flatfoot was achieved in all cases. Despite this, most patients continued to report pain and dysfunction postoperatively. Participants post LCL demonstrated similar passive and active movement of the medial column when we compared the operated and the nonoperated sides. However, participants post LCL demonstrated significantly greater first metatarsal passive range of motion and first metatarsal dorsiflexion during gait than did controls (P < .01 for all pairwise comparisons). Patients undergoing LCL for correction of stage II adult-acquired flatfoot deformity experience mixed outcomes and similar foot kinematics as the uninvolved limb despite radiographic correction of deformity. These patients maintain a low arch posture similar to their uninvolved limb. The consequence is that first metatarsal movement operates at the end range of dorsiflexion and patients do not obtain full hindfoot inversion at push-off. Longitudinal data are necessary to make a more valid comparison of the effects of surgical correction measured using radiographs and dynamic foot posture during gait. Level III, comparative series.

Motion Controlled Gait Enhancing Mobile Shoe for Rehabilitation

PubMed Central

Handzic, Ismet; Vasudevan, Erin V.; Reed, Kyle B.

2011-01-01

Walking on a split-belt treadmill, which has two belts that can be run at different speeds, has been shown to improve walking patterns post-stroke. However, these improvements are only temporarily retained once individuals transition to walking over ground. We hypothesize that longer-lasting effects would be observed if the training occurred during natural walking over ground, as opposed to on a treadmill. In order to study such long-term effects, we have developed a mobile and portable device which can simulate the same gait altering movements experienced on a split-belt treadmill. The new motion controlled gait enhancing mobile shoe improves upon the previous version’s drawbacks. This version of the GEMS has motion that is continuous, smooth, and regulated with on-board electronics. A vital component of this new design is the Archimedean spiral wheel shape that redirects the wearer’s downward force into a horizontal backward motion. The design is passive and does not utilize any motors. Its motion is regulated only by a small magnetic particle brake. Further experimentation is needed to evaluate the long-term after-effects. PMID:22275620

Passive swimming in viscous oscillatory flows

NASA Astrophysics Data System (ADS)

Jo, Ikhee; Huang, Yangyang; Zimmermann, Walter; Kanso, Eva

2016-12-01

Fluid-based locomotion at low Reynolds number is subject to the constraints of Purcell's scallop theorem: reciprocal shape kinematics identical under a time-reversal symmetry cannot cause locomotion. In particular, a single degree-of-freedom scallop undergoing opening and closing motions cannot swim. Most strategies for symmetry breaking and locomotion rely on direct control of the swimmer's shape kinematics. Less is known about indirect control via actuation of the fluid medium. To address how such indirect actuation strategies can lead to locomotion, we analyze a Λ -shaped model system analogous to Purcell's scallop but able to deform passively in oscillatory flows. Neutrally buoyant scallops undergo no net locomotion. We show that dense, elastic scallops can exhibit passive locomotion in zero-mean oscillatory flows. We examine the efficiency of swimming parallel to the background flow and analyze the stability of these motions. We observe transitions from stable to unstable swimming, including ordered transitions from fluttering to chaoticlike motions and tumbling. Our results demonstrate that flow oscillations can be used to passively actuate and control the motion of microswimmers, which may be relevant to applications such as surgical robots and cell sorting and manipulation in microfluidic devices.

Kinematic Analysis of Cpm Machine Supporting to Rehabilitation Process after Surgical Knee Arthroscopy and Arthroplasty

NASA Astrophysics Data System (ADS)

Trochimczuk, R.; Kuźmierowski, T.

2014-11-01

Existing commercial solutions of the CPM (Continuous Passive Motion) machines are described in the paper. Based on the analysis of existing solutions we present our conceptual solution to support the process of rehabilitation of the knee joint which is necessary after arthroscopic surgery. For a given novel structure we analyze and present proprietary algorithms and the computer application to simulate the operation of our PCM device. In addition, we suggest directions for further research.

Random walk of passive tracers among randomly moving obstacles.

PubMed

Gori, Matteo; Donato, Irene; Floriani, Elena; Nardecchia, Ilaria; Pettini, Marco

2016-04-14

This study is mainly motivated by the need of understanding how the diffusion behavior of a biomolecule (or even of a larger object) is affected by other moving macromolecules, organelles, and so on, inside a living cell, whence the possibility of understanding whether or not a randomly walking biomolecule is also subject to a long-range force field driving it to its target. By means of the Continuous Time Random Walk (CTRW) technique the topic of random walk in random environment is here considered in the case of a passively diffusing particle among randomly moving and interacting obstacles. The relevant physical quantity which is worked out is the diffusion coefficient of the passive tracer which is computed as a function of the average inter-obstacles distance. The results reported here suggest that if a biomolecule, let us call it a test molecule, moves towards its target in the presence of other independently interacting molecules, its motion can be considerably slowed down.

Medial gastrocnemius muscle stiffness cannot explain the increased ankle joint range of motion following passive stretching in children with cerebral palsy.

PubMed

Kalkman, Barbara M; Bar-On, Lynn; Cenni, Francesco; Maganaris, Constantinos N; Bass, Alfie; Holmes, Gill; Desloovere, Kaat; Barton, Gabor J; O'Brien, Thomas D

2018-03-01

What is the central question of this study? Can the increased range of motion seen acutely after stretching in children with cerebral palsy be explained by changes in the stiffness of the medial gastrocnemius fascicles? What is the main finding and its importance? We show, for the first time, that passive muscle and tendon properties are not changed acutely after a single bout of stretching in children with cerebral palsy and, therefore, do not contribute to the increase in range of motion. This contradicts common belief and what happens in healthy adults. Stretching is often used to increase or maintain the joint range of motion (ROM) in children with cerebral palsy (CP), but the effectiveness of these interventions is limited. Therefore, our aim was to determine the acute changes in muscle-tendon lengthening properties that contribute to increased ROM after a bout of stretching in children with CP. Eleven children with spastic CP [age 12.1 (3 SD) years, 5/6 hemiplegia/diplegia, 7/4 gross motor function classification system level I/II] participated. Each child received three sets of five × 20 s passive, manual static dorsiflexion stretches separated by 30 s rest, with 60 s rest between sets. Before and immediately after stretching, ultrasound was used to measure medial gastrocnemius fascicle lengthening continuously over the full ROM and an individual common ROM pre- to post-stretching. Simultaneously, three-dimensional motion of two marker clusters on the shank and the foot was captured to calculate ankle angle, and ankle joint torque was calculated from manually applied torques and forces on a six degrees-of-freedom load cell. After stretching, the ROM was increased [by 9.9 (12.0) deg, P = 0.005]. Over a ROM common to both pre- and post-measurements, there were no changes in fascicle lengthening or torque. The maximal ankle joint torque tolerated by the participants increased [by 2.9 (2.4) N m, P = 0.003], and at this highest passive torque the maximal fascicle length was 2.8 (2.4) mm greater (P = 0.009) when compared with before stretching. These results indicate that the stiffness of the muscle fascicles in children with CP remains unaltered by an acute bout of stretching. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Axial bone-socket displacement for persons with a traumatic transtibial amputation: The effect of elevated vacuum suspension at progressive body-weight loads.

PubMed

Darter, Benjamin J; Sinitski, Kirill; Wilken, Jason M

2016-10-01

Elevated vacuum suspension systems use a pump to draw air from the socket with the intent of reducing bone-socket motion as compared to passive suction systems. However, it remains unknown if elevated vacuum suspension systems decrease limb displacement uniformly during transitions from unloaded to full-body-weight support. To compare limb-socket motion between elevated vacuum and passive suction suspension sockets using a controlled loading paradigm. Comparative analysis. Persons with transtibial amputation were assessed while wearing either an elevated vacuum or passive suction suspension socket. Digital video fluoroscopy was used to measure axial bone-socket motion while the limb was loaded in 20% body-weight increments. An analysis of variance model was used to compare between suspension types. Total axial displacement (0%-100% body weight) was significantly lower using the elevated vacuum (vacuum: 1.3 cm, passive suction: 1.8 cm; p < 0.0001). Total displacement decreased primarily due to decreased motion during initial loading (0%-20%; p < 0.0001). Other body-weight intervals were not significantly different between systems. Elevated vacuum suspension reduced axial limb-socket motion by maintaining position of the limb within the socket during unloaded conditions. Elevated vacuum provided no meaningful improvement in limb-socket motion past initial loading. Excessive bone-socket motion contributes to poor residual limb health. Our results suggest elevated vacuum suspensions can reduce this axial displacement. Visual assessment of the images suggests that this occurs through the reduction or elimination of the air pocket between the liner and socket wall while the limb is unloaded. © The International Society for Prosthetics and Orthotics 2015.

Passive Range of Motion in a Population-Based Sample of Children with Spastic Cerebral Palsy Who Walk

ERIC Educational Resources Information Center

McDowell, Brona C.; Salazar-Torres, Jose J.; Kerr, Claire; Cosgrove, Aidan P.

2012-01-01

-While passive range of motion (PROM) is commonly used to inform decisions on therapeutic management, knowledge of PROM of children with spastic cerebral palsy (CP) is limited. A population-based sample of 178 children with spastic CP (110 male; unilateral, n = 94; bilateral, n = 84; age range 4-17 years) and 68 typically developing children (24…

A One-Axis-Controlled Magnetic Bearing and Its Performance

NASA Astrophysics Data System (ADS)

Li, Lichuan; Shinshi, Tadahiko; Kuroki, Jiro; Shimokohbe, Akira

Magnetic bearings (MBs) are complex machines in which sensors and controllers must be used to stabilize the rotor. A standard MB requires active control of five motion axes, imposing significant complexity and high cost. In this paper we report a very simple MB and its experimental testing. In this MB, the rotor is stabilized by active control of only one motion axis. The other four motion axes are passively stabilized by permanent magnets and appropriate magnetic circuit design. In rotor radial translational motion, which is passively stabilized, a resonant frequency of 205Hz is achieved for a rotor mass of 11.5×10-3kg. This MB features virtually zero control current and zero rotor iron loss (hysteresis and eddy current losses). Although the rotational speed and accuracy are limited by the resonance of passively stabilized axes, the MB is still suitable for applications where cost is critical but performance is not, such as cooling fans and auxiliary support for aerodynamic bearings.

Motion analysis report

NASA Technical Reports Server (NTRS)

Badler, N. I.

1985-01-01

Human motion analysis is the task of converting actual human movements into computer readable data. Such movement information may be obtained though active or passive sensing methods. Active methods include physical measuring devices such as goniometers on joints of the body, force plates, and manually operated sensors such as a Cybex dynamometer. Passive sensing de-couples the position measuring device from actual human contact. Passive sensors include Selspot scanning systems (since there is no mechanical connection between the subject's attached LEDs and the infrared sensing cameras), sonic (spark-based) three-dimensional digitizers, Polhemus six-dimensional tracking systems, and image processing systems based on multiple views and photogrammetric calculations.

Position-Specific Hip and Knee Kinematics in NCAA Football Athletes

PubMed Central

Deneweth, Jessica M.; Pomeroy, Shannon M.; Russell, Jason R.; McLean, Scott G.; Zernicke, Ronald F.; Bedi, Asheesh; Goulet, Grant C.

2014-01-01

Background: Femoroacetabular impingement is a debilitating hip condition commonly affecting athletes playing American football. The condition is associated with reduced hip range of motion; however, little is known about the range-of-motion demands of football athletes. This knowledge is critical to effective management of this condition. Purpose: To (1) develop a normative database of game-like hip and knee kinematics used by football athletes and (2) analyze kinematic data by playing position. The hypothesis was that kinematics would be similar between running backs and defensive backs and between wide receivers and quarterbacks, and that linemen would perform the activities with the most erect lower limb posture. Study Design: Descriptive laboratory study. Methods: Forty National Collegiate Athletic Association (NCAA) football athletes, representing 5 playing positions (quarterback, defensive back, running back, wide receiver, offensive lineman), executed game-like maneuvers while lower body kinematics were recorded via optical motion capture. Passive hip range of motion at 90° of hip flexion was assessed using a goniometer. Passive range of motion, athlete physical dimensions, hip function, and hip and knee rotations were submitted to 1-way analysis of variance to test for differences between playing positions. Correlations between maximal hip and knee kinematics and maximal hip kinematics and passive range of motion were also computed. Results: Hip and knee kinematics were similar across positions. Significant differences arose with linemen, who used lower maximal knee flexion (mean ± SD, 45.04° ± 7.27°) compared with running backs (61.20° ± 6.07°; P < .001) and wide receivers (54.67° ± 6.97°; P = .048) during the cut. No significant differences were found among positions for hip passive range of motion (overall means: 102° ± 15° [flexion]; 25° ± 9° [internal rotation]; 25° ± 8° [external rotation]). Several maximal hip measures were found to negatively correlate with maximal knee kinematics. Conclusion: A normative database of hip and knee kinematics utilized by football athletes was developed. Position-specific analyses revealed that linemen use smaller joint motions when executing dynamic tasks but do not demonstrate passive range of motion deficits compared with other positions. Clinical Relevance: Knowledge of requisite game-like hip and knee ranges of motion is critical for developing goals for nonoperative or surgical recovery of hip and knee range of motion in the symptomatic athlete. These data help to identify playing positions that require remedial hip-related strength and conditioning protocols. Negative correlations between hip and knee kinematics indicated that constrained hip motion, as seen in linemen, could promote injurious motions at the knee. PMID:26535334

Direction detection thresholds of passive self-motion in artistic gymnasts.

PubMed

Hartmann, Matthias; Haller, Katia; Moser, Ivan; Hossner, Ernst-Joachim; Mast, Fred W

2014-04-01

In this study, we compared direction detection thresholds of passive self-motion in the dark between artistic gymnasts and controls. Twenty-four professional female artistic gymnasts (ranging from 7 to 20 years) and age-matched controls were seated on a motion platform and asked to discriminate the direction of angular (yaw, pitch, roll) and linear (leftward-rightward) motion. Gymnasts showed lower thresholds for the linear leftward-rightward motion. Interestingly, there was no difference for the angular motions. These results show that the outstanding self-motion abilities in artistic gymnasts are not related to an overall higher sensitivity in self-motion perception. With respect to vestibular processing, our results suggest that gymnastic expertise is exclusively linked to superior interpretation of otolith signals when no change in canal signals is present. In addition, thresholds were overall lower for the older (14-20 years) than for the younger (7-13 years) participants, indicating the maturation of vestibular sensitivity from childhood to adolescence.

What is the impingement-free range of motion of the asymptomatic hip in young adult males?

PubMed

Larkin, Brian; van Holsbeeck, Marnix; Koueiter, Denise; Zaltz, Ira

2015-04-01

Femoroacetabular impingement is a recognized cause of chondrolabral injury. Although surgical treatment for impingement seeks to improve range of motion, there are very little normative data on dynamic impingement-free hip range of motion (ROM) in asymptomatic people. Hip ultrasound demonstrates labral anatomy and femoral morphology and, when used dynamically, can assist in measuring range of motion. The purposes of this study were (1) to measure impingement-free hip ROM until labral deflection is observed; and (2) to measure the maximum degree of sagittal plane hip flexion when further flexion is limited by structural femoroacetabular abutment. Forty asymptomatic adult male volunteers (80 hips) between the ages of 21 and 35 years underwent bilateral static and dynamic hip ultrasound examination. Femoral morphology was characterized and midsagittal flexion passive ROM was measured at two points: (1) at the initiation of labral deformation; and (2) at maximum flexion when the femur impinged on the acetabular rim. The mean age of the subjects was 28 ± 3 years and the mean body mass index was 25 ± 4 kg/m(2). Mean impingement-free hip passive flexion measured from full extension to initial labral deflection was 68° ± 17° (95% confidence interval [CI], 65-72). Mean maximum midsagittal passive flexion, measured at the time of bony impingement, was 96° ± 6° (95% CI, 95-98). Using dynamic ultrasound, we found that passive ROM in the asymptomatic hip was much less than the motion reported in previous studies. Measuring ROM using ultrasound is more accurate because it allows anatomic confirmation of terminal hip motion. Surgical procedures used to treat femoroacetabular impingement are designed to restore or increase hip ROM and their results should be evaluated in light of precise normative data. This study suggests that normal passive impingement-free femoroacetabular flexion in the young adult male is approximately 95°.

The effect of tibio-femoral traction mobilization on passive knee flexion motion impairment and pain: a case series

PubMed Central

Maher, Sara; Creighton, Doug; Kondratek, Melodie; Krauss, John; Qu, Xianggui

2010-01-01

The purpose of this case series was to explore the effects of tibio-femoral (TF) manual traction on pain and passive range of motion (PROM) in individuals with unilateral motion impairment and pain in knee flexion. Thirteen participants volunteered for the study. All participants received 6 minutes of TF traction mobilization applied at end-range passive knee flexion. PROM measurements were taken before the intervention and after 2, 4, and 6 minutes of TF joint traction. Pain was measured using a visual analog scale with the TF joint at rest, at end-range passive knee flexion, during the application of joint traction, and immediately post-treatment. There were significant differences in PROM after 2 and 4 minutes of traction, with no significance noted after 4 minutes. A significant change in knee flexion of 25.9°, which exceeded the MDC95, was found when comparing PROM measurements pre- to final intervention. While pain did not change significantly over time, pain levels did change significantly during each treatment session. Pain significantly increased when the participant’s knee was passively flexed to end range; it was reduced, although not significantly, during traction mobilization; and it significantly decreased following traction. This case series supports TF joint traction as a means of stretching shortened articular and periarticular tissues without increasing reported levels of pain during or after treatment. In addition, this is the first study documenting the temporal aspects of treatment effectiveness in motion restoration. PMID:21655421

Optokinetic motion sickness - Attenuation of visually-induced apparent self-rotation by passive head movements

NASA Technical Reports Server (NTRS)

Teixeira, R. A.; Lackner, J. R.

1979-01-01

An experimental study was conducted on seven normal subjects to evaluate the effectiveness of passive head movements in suppressing the optokinetically-induced illusory self-rotation. Visual simulation was provided by a servo-controlled optokinetic drum. Each subject participated in two experimental sessions. In one condition, the subject's head remained stationary while he gazed passively at a moving stripe pattern. In the other, he gazed passively and relaxed his neck muscles while his head was rotated from side to side. It appears that suppression of optokinetically-induced illusory self-rotation with passive head movements results from the operation of a spatial constancy mechanism interrelating visual, vestibular, and kinesthetic information on ongoing body orientation. The results support the view that optokinetic 'motion sickness' is related, at least in part, to an oculomotor disturbance rather than a visually triggered disturbance of specifically vestibular etiology.

The initial safe range of motion of the ankle joint after three methods of internal fixation of simulated fractures of the medial malleolus.

PubMed

Shimamura, Yoshio; Kaneko, Kazuo; Kume, Kazuhiko; Maeda, Mutsuhiro; Iwase, Hideaki

2006-07-01

Previous studies have demonstrated the safe passive range of ankle motion for inter-bone stiffness after internal fixation under load but there is a lack of information about the safe range of ankle motion for early rehabilitation in the absence of loading. The present study was designed to assess the effect of ankle movement on inter-bone displacement characteristics of medial malleolus fractures following three types of internal fixation to determine the safe range of motion. Five lower legs obtained during autopsy were used to assess three types of internal fixation (two with Kirschner-wires alone; two with Kirschner-wires plus tension band wiring; and, one with an AO/ASIF malleolar screw alone). Following a simulated fracture by sawing through the medial malleolus the displacement between the fractured bone ends was measured during a passive range of movement with continuous monitoring using omega (Omega) shaped transducers and a biaxial flexible goniometer. Statistical analysis was performed with repeated measures analysis of variance. Inter-bone displacement was not proportional to the magnitude of movement throughout the range of ankle motion as, when separation exceeded 25 microm, there was increasingly wide separation as plantar-flexion or dorsal-flexion was increased. There was no statistical significant difference between the small amount of inter-bone displacement observed with three types of fixation within the safe range of dorsal-flexion and plantar-flexion for early rehabilitation. However the inter-bone separation when fixation utilized two Kirschner-wires alone tended to be greater than when using the other two types of fixation during dorsal-flexion and eversion. The present study revealed a reproducible range of ankle motion for early rehabilitation which was estimated to be within the range of 20 degrees of dorsal-flexion and 10 degrees of plantar-flexion without eversion. Also, internal fixation with two Kirschner-wires alone does not seem to provide stability achieved by the other two forms of fixation.

Can passive mobilization provide clinically-relevant brain stimulation? A pilot EEG and NIRS study on healthy subjects.

PubMed

Pittaccio, Simone; Garavaglia, Lorenzo; Molteni, Erika; Guanziroli, Eleonora; Zappasodi, Filippo; Beretta, Elena; Strazzer, Sandra; Molteni, Franco; Villa, Elena; Passaretti, Francesca

2013-01-01

Lower limb rehabilitation is a fundamental part of post-acute care in neurological disease. Early commencement of active workout is often prevented by paresis, thus physical treatment may be delayed until patients regain some voluntary command of their muscles. Passive mobilization of the affected joints is mostly delivered in order to safeguard tissue properties and shun circulatory problems. The present paper investigates the potential role of early passive motion in stimulating cortical areas of the brain devoted to the control of the lower limb. An electro-mechanical mobilizer for the ankle joint (Toe-Up!) was implemented utilizing specially-designed shape-memory-alloy-based actuators. This device was constructed to be usable by bedridden subjects. Besides, the slowness and gentleness of the imparted motion, make it suitable for patients in a very early stage of their recovery. The mobilizer underwent technical checks to confirm reliability and passed the required safety tests for electric biomedical devices. Four healthy volunteers took part in the pre-clinical phase of the study. The protocol consisted in measuring of brain activity by EEG and NIRS in four different conditions: rest, active dorsiflexion of the ankle, passive mobilization of the ankle, and assisted motion of the same joint. The acquired data were processed to obtain maps of cortical activation, which were then compared. The measurements collected so far show that there is a similar pattern of activity between active and passive/assisted particularly in the contralateral premotor areas. This result, albeit based on very few observations, might suggest that passive motion provides somatosensory afferences that are processed in a similar manner as for voluntary control. Should this evidence be confirmed by further trials on healthy individuals and neurological patients, it could form a basis for a clinical use of early passive exercise in supporting central functional recovery.

Rehabilitation after cell transplantation for cartilage defects.

PubMed

Deszczynski, J; Slynarski, K

2006-01-01

Rehabilitation is a key element of successful treatment of cartilage defects with cell transplantation. The process of graft maturation takes approximately 18 months and cannot be accelerated, but requires carefully introduced steps leading to early recovery of joint function. Rehabilitation starts at 8 hours after surgery with the continuous passive motion (CPM) exercises and physiotherapy. For the first 6 weeks, patients continue with CPM in the range of 0 degrees to 45 degrees for femoral and tibial defects and 0 degrees to 30 degrees for patellofemoral joint reconstruction. Isometric muscle training and scar manual therapy are introduced. Patients are allowed to weight-bear as tolerated from the second week after surgery. After this initial phase, from 6 to 8 weeks after surgery, rehabilitation is accelerated with increased load-bearing and progressive range of motion to full flexion. Usually patients are able to walk without crutches in this time. Proprioceptive training is introduced with the advance of pain-free full range of motion and no discomfort with full weight-bearing. At 6 months after surgery, most patients recover joint function, making it possible for them to return to daily living activities. However, they need to continue with muscle, proprioceptive, and sports-specific rehabilitation exercises. The rehabilitation process is complicated, requiring close cooperation between the patient and surgeon-physiotherapist team to understand the symptoms and address them in a timely fashion.

The effect of age on hamstring passive properties after a 10-week stretch training

PubMed Central

Haab, Thomas; Wydra, Georg

2017-01-01

[Purpose] Degenerative changes take place in the musculoskeletal system of elderly people, resulting in a reduced range of motion. For this reason, stretch training is recommended for elderly individuals. To date, there have been no studies of the adaptations of the passive properties of muscles following long-term stretch training. The aim of this study is to investigate the hamstring elasticity of elderly people following a 10-week stretch training and compare the results to a younger cohort. [Subjects and Methods] The experimental groups consisted of 15 younger (24.0 ± 4.0 years) and 14 older (65.1 ± 7.9 years) individuals. Both experimental groups undertook a standardised 10-week static passive hamstring stretch training. Passive properties of the hamstring were measured with an instrumented Straight Leg Raise Test. [Results] After a 10-week stretch training, there were increases in range of motion, passive resistive force and passive elastic energy in both age groups. Passive elastic stiffness decreased. Changes of hamstring passive properties did not differ significantly between age groups after a 10-week stretch training. [Conclusion] Increasing age has a negative effect on muscle passive properties, but older individuals benefit from regular stretch training, just as younger individuals do. PMID:28626322

Towards low back support with a passive biomimetic exo-spine.

PubMed

Naf, Matthias B; De Rijcke, Laura; Guerrero, Carlos Rodriguez; Millard, Matthew; Vanderborght, Bram; Lefeber, Dirk

2017-07-01

Low-Back Pain (LBP) affects a large portion of the working population. Preventive exoskeletons have been proposed to reduce the moments on the lower back, specifically around the lumbosacral (L5/S1) joint. High correlation has been shown, between reducing the moments around the L5/S1 joint and intervertebral compression forces, which in turn have been identified as a risk factor for developing LBP. However, most passive back support exoskeletons use rigid plates or stiff beams to support the spine that limit the range of motion of the wearer. A large range of motion and versatility are especially desirable for industrial applications. To overcome these limitations, a passive biomimetic exo-spine has been designed, modelled and an initial prototype tested. Its potential to allow for a large range of motion, whilst at the same time limiting the most extreme and potentially harmful postures has been shown.

Hygroscopic motions of fossil conifer cones

NASA Astrophysics Data System (ADS)

Poppinga, Simon; Nestle, Nikolaus; Šandor, Andrea; Reible, Bruno; Masselter, Tom; Bruchmann, Bernd; Speck, Thomas

2017-01-01

Conifer cones represent natural, woody compliant structures which move their scales as passive responses to changes in environmental humidity. Here we report on water-driven opening and closing motions in coalified conifer cones from the Eemian Interglacial (approx. 126,000-113,000 years BP) and from the Middle Miocene (approx. 16.5 to 11.5 million years BP). These cones represent by far the oldest documented evidence of plant parts showing full functionality of such passive hydraulically actuated motion. The functional resilience of these structures is far beyond the biological purpose of seed dispersal and protection and is because of a low level of mineralization of the fossils. Our analysis emphasizes the functional-morphological integrity of these biological compliant mechanisms which, in addition to their biological fascination, are potentially also role models for resilient and maintenance-free biomimetic applications (e.g., adaptive and autonomously moving structures including passive hydraulic actuators).

Continuous passive motion and its effects on knee flexion after total knee arthroplasty in patients with knee osteoarthritis.

PubMed

Liao, Chun-De; Huang, Yi-Ching; Lin, Li-Fong; Chiu, Yen-Shuo; Tsai, Jui-Chen; Chen, Chun-Lung; Liou, Tsan-Hon

2016-08-01

This study evaluated the effects of continuous passive motion (CPM) on accelerated flexion after total knee arthroplasty (TKA) and whether CPM application measures (i.e. initial angle and daily increment) are associated with functional outcomes. A retrospective investigation was conducted at the rehabilitation centre of a university-based teaching hospital. Patients who received CPM therapy immediately after TKA surgery were categorized into rapid-, normal-, and slow-progress groups according to their response to CPM during their acute inpatient stay. Knee pain, passive knee flexion, and knee function-measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-were assessed preoperatively at discharge and at 3- and 6-month outpatient follow-up visits. A total of 354 patients were followed for 6 months after inpatient-stay discharge. The patients in the rapid-progress group (n = 119) exhibited significantly greater knee flexions than those in the slow-progress group did (n = 103) at the 3-month follow-up [mean difference (MD) = 10.3°, 95 % confidence interval (CI) 4.3°-16.3°, p < 0.001] and 6-month follow-up (MD = 10.9°, 95 % CI 6.3°-15.6°, p < 0.001). Significant WOMAC score differences between the rapid- and slow-progress groups were observed at the 3-month follow-up (MD = 7.2, 95 % CI 5.4-9.1, p < 0.001) and 6-month follow-up (MD = 16.1, 95 % CI 13.4-18.7, p < 0.001). CPM initial angles and rapid progress significantly predicted short- and long-term outcomes in knee flexion and WOMAC scores (p < 0.001). When CPM is used, early application with initial high flexion and rapid progress benefits knee function up to 6 months after TKA. II.

Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to physiotherapy, after total knee arthroplasty.

PubMed

Lenssen, Ton A F; van Steyn, Mike J A; Crijns, Yvonne H F; Waltjé, Eddie M H; Roox, George M; Geesink, Ruud J T; van den Brandt, Piet A; De Bie, Rob A

2008-04-29

Adequate and intensive rehabilitation is an important requirement for successful total knee arthroplasty. Although research suggests that Continuous Passive Motion (CPM) should be implemented in the first rehabilitation phase after surgery, there is substantial debate about the duration of each session and the total period of CPM application. A Cochrane review on this topic concluded that short-term use of CPM leads to greater short-term range of motion. It also suggested, however, that future research should concentrate on the treatment period during which CPM should be administered. In a randomised controlled trial we investigated the effectiveness of prolonged CPM use in the home situation as an adjunct to standardised PT. Efficacy was assessed in terms of faster improvements in range of motion (RoM) and functional recovery, measured at the end of the active treatment period, 17 days after surgery. Sixty patients with knee osteoarthritis undergoing TKA and experiencing early postoperative flexion impairment were randomised over two treatment groups. The experimental group received CPM + PT for 17 consecutive days after surgery, whereas the usual care group received the same treatment during the in-hospital phase (i.e. about four days), followed by PT alone (usual care) in the first two weeks after hospital discharge. From 18 days to three months after surgery, both groups received standardised PT. The primary focus of rehabilitation was functional recovery (e.g. ambulation) and regaining RoM in the knee. Prolonged use of CPM slightly improved short-term RoM in patients with limited RoM at the time of discharge after total knee arthroplasty when added to a semi-standard PT programme. Assessment at 6 weeks and three months after surgery found no long-term effects of this intervention Neither did we detect functional benefits of the improved RoM at any of the outcome assessments. Although results indicate that prolonged CPM use might have a small short-term effect on RoM, routine use of prolonged CPM in patients with limited RoM at hospital discharge should be reconsidered, since neither long-term effects nor transfer to better functional performance was detected. ISRCTN85759656.

Simultaneous 3D tracking of passive tracers and microtubule bundles in an active gel

NASA Astrophysics Data System (ADS)

Fan, Yi; Breuer, Kenneth S.; Fluids Team

Kinesin-driven microtubule bundles generate a spontaneous flow in unconfined geometries. They exhibit properties of active matter, including the emergence of collective motion, reduction of apparent viscosity and consumption of local energy. Here we present results from 3D tracking of passive tracers (using Airy rings and 3D scanning) synchronized with 3D measurement of the microtubule bundles motion. This technique is applied to measure viscosity variation and collective flow in a confined geometry with particular attention paid to the self-pumping system recently reported by Wu et al. (2016). Results show that the viscosity in an equilibrium microtubule network is around half that of the isotropic unbundled microtubule solution. Cross-correlations of the active microtubule network and passive tracers define a neighborhood around microtubule bundles in which passive tracers are effectively transported. MRSEC NSF.

Anterior Cruciate Ligament Reconstruction Rehabilitation

PubMed Central

Wright, Rick W.; Haas, Amanda K.; Anderson, Joy; Calabrese, Gary; Cavanaugh, John; Hewett, Timothy E.; Lorring, Dawn; McKenzie, Christopher; Preston, Emily; Williams, Glenn; Amendola, Annunziato

2015-01-01

Context: Anterior cruciate ligament (ACL) reconstruction rehabilitation has evolved over the past 20 years. This evolution has been driven by a variety of level 1 and level 2 studies. Evidence Acquisition: The MOON Group is a collection of orthopaedic surgeons who have developed a prospective longitudinal cohort of the ACL reconstruction patients. To standardize the management of these patients, we developed, in conjunction with our physical therapy committee, an evidence-based rehabilitation guideline. Study Design: Clinical review. Level of Evidence: Level 2. Results: This review was based on 2 systematic reviews of level 1 and level 2 studies. Recently, the guideline was updated by a new review. Continuous passive motion did not improve ultimate motion. Early weightbearing decreases patellofemoral pain. Postoperative rehabilitative bracing did not improve swelling, pain range of motion, or safety. Open chain quadriceps activity can begin at 6 weeks. Conclusion: High-level evidence exists to determine appropriate ACL rehabilitation guidelines. Utilizing this protocol follows the best available evidence. PMID:26131301

Postoperative stiff shoulder after open rotator cuff repair: a 3- to 20-year follow-up study.

PubMed

Vastamäki, H; Vastamäki, M

2014-12-01

Stiffness after a rotator cuff tear is common. So is stiffness after an arthroscopic rotator cuff repair. In the literature, however, postoperative restriction of passive range of motion after open rotator cuff repair in shoulders with free passive range of motion at surgery has seldom been recognized. We hypothesize that this postoperative stiffness is more frequent than recognized and slows the primary postoperative healing after a rotator cuff reconstruction. We wondered how common is postoperative restriction of both active and passive range of motion after open rotator cuff repair in shoulders with free passive preoperative range of motion, how it recovers, and whether this condition influences short- and long-term results of surgery. We also explored factors predicting postoperative shoulder stiffness. We retrospectively identified 103 postoperative stiff shoulders among 416 consecutive open rotator cuff repairs, evaluating incidence and duration of stiffness, short-term clinical results and long-term range of motion, pain relief, shoulder strength, and functional results 3-20 (mean 8.7) years after surgery in 56 patients. The incidence of postoperative shoulder stiffness was 20%. It delayed primary postoperative healing by 3-6 months and resolved during a mean 6.3 months postoperatively. External rotation resolved first, corresponding to that of the controls at 3 months; flexion and abduction took less than 1 year after surgery. The mean summarized range of motion (flexion + abduction + external rotation) increased as high as 93% of the controls' range of motion by 6 months and 100% by 1 year. Flexion, abduction, and internal rotation improved to the level of the contralateral shoulders as did pain, strength, and function. Age at surgery and condition of the biceps tendon were related to postoperative stiffness. Postoperative stiff shoulder after open rotator cuff repair is a common complication resolving in 6-12 months with good long-term results. © The Finnish Surgical Society 2013.

Comparison of 2 Dosages of Stretching Treatment in Infants with Congenital Muscular Torticollis: A Randomized Trial.

PubMed

He, Lu; Yan, Xiaohua; Li, Jinling; Guan, Buyun; Ma, Liying; Chen, Ying; Mai, Jianning; Xu, Kaishou

2017-05-01

To compare the short-term efficacy of 2 dosages of stretching treatment on the clinical outcomes in infants with congenital muscular torticollis. This was a prospective randomized controlled study. Fifty infants with congenital muscular torticollis who were randomly assigned to 100-times stretching group and 50-times stretching group received stretching treatment for the affected sternocleidomastoid muscle. The outcomes including the head tilt, the cervical passive range of motion, and the muscle function of cervical lateral flexors determined by the muscle function scale were assessed at baseline and at 4 and 8 weeks after treatment. The sternocleidomastoid muscle growth analyzed by the thickness ratio of sternocleidomastoid muscles was measured using ultrasonography at baseline and 8 weeks after treatment. Except the ratio of muscle function scale scores, the postintervention outcomes were all significantly improved in both groups compared with baseline (P < 0.05). The 100-times stretching group showed greater improvement compared with 50-times stretching group in head tilt and cervical passive range of motion at 4 and 8 weeks after treatment (P < 0.05). Stretching treatment of 2 dosages may effectively improve head tilt, cervical passive range of motion, and sternocleidomastoid muscle growth in infants with congenital muscular torticollis. The stretching treatment of 100 times per day is likely to associate with greater improvement in head tilt and cervical passive range of motion.

Effects of an Elastic Hamstring Assistance Device During Downhill Running

PubMed Central

Aldret, Randy L; Trahan, Brittany A; Davis, Greggory; Campbell, Brian; Bellar, David M

2017-01-01

Abstract The purpose of this study was to determine the appropriateness of using an elastic hamstring assistance device to reduce perceived levels of soreness, increase isometric strength, increase passive range of motion, and decrease biomarkers of muscle damage after eccentric exercise, specifically, downhill running This study was conducted in a university exercise physiology laboratory placing sixteen apparently healthy males (X = 21.6 ± 2.5 years) into two groups using a pre-test/post-test design. Pre-intervention measures taken included participants’ body height, body mass, body fat, capillary blood samples, VO2max, isometric hamstring strength at 45 and 90 degrees of flexion and passive hamstring range of motion. Post-intervention measures included blood biomarkers, passive range of motion, the perceived level of soreness and isometric strength. An analysis of normality of data was initially conducted followed by multivariate analysis of variance (MANOVA) of hamstring strength at 45 and 90 degrees of flexion, blood myoglobin and passive range of motion of the hamstrings. Statistically significant changes were noted in subject-perceived muscle soreness and isometric strength at 90 degrees at the 24-hour post-exercise trial measure between the two groups. Results would suggest the findings could be explained by the decrease in muscle soreness from utilizing the device during the exercise trial. Further research should be conducted to address sample size issues and to determine if the results are comparable on different surfaces. PMID:28713460

Using Passive Sensing to Estimate Relative Energy Expenditure for Eldercare Monitoring

PubMed Central

2012-01-01

This paper describes ongoing work in analyzing sensor data logged in the homes of seniors. An estimation of relative energy expenditure is computed using motion density from passive infrared motion sensors mounted in the environment. We introduce a new algorithm for detecting visitors in the home using motion sensor data and a set of fuzzy rules. The visitor algorithm, as well as a previous algorithm for identifying time-away-from-home (TAFH), are used to filter the logged motion sensor data. Thus, the energy expenditure estimate uses data collected only when the resident is home alone. Case studies are included from TigerPlace, an Aging in Place community, to illustrate how the relative energy expenditure estimate can be used to track health conditions over time. PMID:25266777

Passive in-home measurement of stride-to-stride gait variability comparing vision and Kinect sensing.

PubMed

Stone, Erik E; Skubic, Marjorie

2011-01-01

We present an analysis of measuring stride-to-stride gait variability passively, in a home setting using two vision based monitoring techniques: anonymized video data from a system of two web-cameras, and depth imagery from a single Microsoft Kinect. Millions of older adults fall every year. The ability to assess the fall risk of elderly individuals is essential to allowing them to continue living safely in independent settings as they age. Studies have shown that measures of stride-to-stride gait variability are predictive of falls in older adults. For this analysis, a set of participants were asked to perform a number of short walks while being monitored by the two vision based systems, along with a marker based Vicon motion capture system for ground truth. Measures of stride-to-stride gait variability were computed using each of the systems and compared against those obtained from the Vicon.

Distance underestimation in virtual space is sensitive to gender but not activity-passivity or mode of interaction.

PubMed

Foreman, Nigel; Sandamas, George; Newson, David

2004-08-01

Four groups of undergraduates (half of each gender) experienced a movement along a corridor containing three distinctive objects, in a virtual environment (VE) with wide-screen projection. One group simulated walking along the virtual corridor using a proprietary step-exercise device. A second group moved along the corridor in conventional flying mode, depressing a keyboard key to initiate continuous forward motion. Two further groups observed the walking and flying participants, by viewing their progress on the screen. Participants then had to walk along a real equivalent but empty corridor, and indicate the positions of the three objects. All groups underestimated distances in the real corridor, the greatest underestimates occurring for the middle distance object. Males' underestimations were significantly lower than females' at all distances. However, there was no difference between the active participants and passive observers, nor between walking and flying conditions.

Acute effects of static stretching on passive stiffness of the hamstring muscles calculated using different mathematical models.

PubMed

Nordez, Antoine; Cornu, Christophe; McNair, Peter

2006-08-01

The aim of this study was to assess the effects of static stretching on hamstring passive stiffness calculated using different data reduction methods. Subjects performed a maximal range of motion test, five cyclic stretching repetitions and a static stretching intervention that involved five 30-s static stretches. A computerised dynamometer allowed the measurement of torque and range of motion during passive knee extension. Stiffness was then calculated as the slope of the torque-angle relationship fitted using a second-order polynomial, a fourth-order polynomial, and an exponential model. The second-order polynomial and exponential models allowed the calculation of stiffness indices normalized to knee angle and passive torque, respectively. Prior to static stretching, stiffness levels were significantly different across the models. After stretching, while knee maximal joint range of motion increased, stiffness was shown to decrease. Stiffness decreased more at the extended knee joint angle, and the magnitude of change depended upon the model used. After stretching, the stiffness indices also varied according to the model used to fit data. Thus, the stiffness index normalized to knee angle was found to decrease whereas the stiffness index normalized to passive torque increased after static stretching. Stretching has significant effects on stiffness, but the findings highlight the need to carefully assess the effect of different models when analyzing such data.

Effects of slow and accelerated rehabilitation protocols on range of motion after arthroscopic rotator cuff repair.

PubMed

Düzgün, İrem; Baltacı, Gül; Turgut, Elif; Atay, O Ahmet

2014-01-01

The aim of the study was to investigate the effects of the early initiation of passive and active range of motion exercises following arthroscopic rotator cuff repair. The study included 40 patients who underwent arthroscopic rotator cuff repair. Patients were quasi-randomly assigned into accelerated (ACCEL) protocol (n=19) and slow (SLOW) protocol (n=21) groups. Patients in both groups were treated with the same protocol. Active range of motion was begun at the 3rd week in the ACCEL group and the 6th week in the SLOW group. Range of motion was recorded at postoperative weeks 3, 5, 8, 12, and 24. While active range of motion for all measurements improved across weeks, there were no differences between groups, with the exception of active total elevation which was greater at all time point measurements in the ACCEL group (p<0.05). The early initiation of passive and gentle controlled active motion exercise following rotator cuff repairs does not appear to affect range of motion in the first 6 postoperative months.

Comparison of epicardial deformation in passive and active isolated rabbit hearts

NASA Astrophysics Data System (ADS)

Ho, Andrew; Tang, Liang; Chiang, Fu-Pen; Lin, Shien-Fong

2007-02-01

Mechanical deformation of isolated rabbit hearts through passive inflation techniques have been a viable form of replicating heart motion, but its relation to the heart's natural active contractions remain unclear. The mechanical properties of the myocardium may show diverse characteristics while in tension and compression. In this study, epicardial strain was measured with the assistance of computer-aided speckle interferometry (CASI)1. CASI tracks the movement of clusters of particles for measuring epicardial deformation. The heart was cannulated and perfused with Tyrode's solution. Silicon carbide particles were applied onto the myocardium to form random speckle pattern images while the heart was allowed to actively contract and stabilize. High resolution videos (1000x1000 pixels) of the left ventricle were taken with a complementary metal oxide semiconductor (CMOS) camera as the heart was actively contracting through electrical pacing at various cycle lengths between 250-800 ms. A latex balloon was then inserted into the left ventricle via left atrium and videos were taken as the balloon was repeatedly inflated and deflated at controlled volumes (1-3 ml/cycle). The videos were broken down into frames and analyzed through CASI. Active contractions resulted in non-uniform circular epicardial and uniaxial contractions at different stages of the motion. In contrast, the passive heart demonstrated very uniform expansion and contraction originating from the source of the latex balloon. The motion of the active heart caused variations in deformation, but in comparison to the passive heart, had a more enigmatic displacement field. The active heart demonstrated areas of large displacement and others with relatively no displacement. Application of CASI was able to successfully distinguish the motions between the active and passive hearts.

Changes in Passive Tension of the Hamstring Muscles During a Simulated Soccer Match.

PubMed

Marshall, Paul W; Lovell, Ric; Siegler, Jason C

2016-07-01

Passive muscle tension is increased after damaging eccentric exercise. Hamstring-strain injury is associated with damaging eccentric muscle actions, but no research has examined changes in hamstring passive muscle tension throughout a simulated sport activity. The authors measured hamstring passive tension throughout a 90-min simulated soccer match (SAFT90), including the warm-up period and every 15 min throughout the 90-min simulation. Passive hamstring tension of 15 amateur male soccer players was measured using the instrumented straight-leg-raise test. Absolute torque (Nm) and slope (Nm/°) of the recorded torque-angular position curve were used for data analysis, in addition to total leg range of motion (ROM). Players performed a 15-min prematch warm-up, then performed the SAFT90 including a 15-min halftime rest period. Reductions in passive stiffness of 20-50° of passive hip flexion of 22.1-29.2% (P < .05) were observed after the warm-up period. During the SAFT90, passive tension increased in the latter 20% of the range of motion of 10.1-10.9% (P < .05) concomitant to a 4.5% increase in total hamstring ROM (P = .0009). The findings of this study imply that hamstring passive tension is reduced after an active warm-up that includes dynamic stretching but does not increase in a pattern suggestive of eccentric induced muscle damage during soccer-specific intermittent exercise. Hamstring ROM and passive tension increases are best explained by improved stretch tolerance.

A two-dimensional computational study on the fluid-structure interaction cause of wing pitch changes in dipteran flapping flight.

PubMed

Ishihara, Daisuke; Horie, T; Denda, Mitsunori

2009-01-01

In this study, the passive pitching due to wing torsional flexibility and its lift generation in dipteran flight were investigated using (a) the non-linear finite element method for the fluid-structure interaction, which analyzes the precise motions of the passive pitching of the wing interacting with the surrounding fluid flow, (b) the fluid-structure interaction similarity law, which characterizes insect flight, (c) the lumped torsional flexibility model as a simplified dipteran wing, and (d) the analytical wing model, which explains the characteristics of the passive pitching motion in the simulation. Given sinusoidal flapping with a frequency below the natural frequency of the wing torsion, the resulting passive pitching in the steady state, under fluid damping, is approximately sinusoidal with the advanced phase shift. We demonstrate that the generated lift can support the weight of some Diptera.

Passive-performance, analysis, and upgrades of a 1-ton seismic attenuation system

NASA Astrophysics Data System (ADS)

Bergmann, G.; Mow-Lowry, C. M.; Adya, V. B.; Bertolini, A.; Hanke, M. M.; Kirchhoff, R.; Köhlenbeck, S. M.; Kühn, G.; Oppermann, P.; Wanner, A.; Westphal, T.; Wöhler, J.; Wu, D. S.; Lück, H.; Strain, K. A.; Danzmann, K.

2017-03-01

The 10 m prototype facility at the Albert-Einstein-institute (AEI) in Hanover, Germany, employs three large seismic attenuation systems to reduce mechanical motion. The AEI seismic-attenuation-system (AEI-SAS) uses mechanical anti-springs in order to achieve resonance frequencies below 0.5 Hz. This system provides passive isolation from ground motion by a factor of about 400 in the horizontal direction at 4 Hz and in the vertical direction at 9 Hz. The presented isolation performance is measured under vacuum conditions using a combination of commercial and custom-made inertial sensors. Detailed analysis of this performance led to the design and implementation of tuned dampers to mitigate the effect of the unavoidable higher order modes of the system. These dampers reduce RMS motion substantially in the frequency range between 10 and 100 Hz in 6 degrees of freedom. The results presented here demonstrate that the AEI-SAS provides substantial passive isolation at all the fundamental mirror-suspension resonances.

An Extended Passive Motion Paradigm for Human-Like Posture and Movement Planning in Redundant Manipulators

PubMed Central

Tommasino, Paolo; Campolo, Domenico

2017-01-01

A major challenge in robotics and computational neuroscience is relative to the posture/movement problem in presence of kinematic redundancy. We recently addressed this issue using a principled approach which, in conjunction with nonlinear inverse optimization, allowed capturing postural strategies such as Donders' law. In this work, after presenting this general model specifying it as an extension of the Passive Motion Paradigm, we show how, once fitted to capture experimental postural strategies, the model is actually able to also predict movements. More specifically, the passive motion paradigm embeds two main intrinsic components: joint damping and joint stiffness. In previous work we showed that joint stiffness is responsible for static postures and, in this sense, its parameters are regressed to fit to experimental postural strategies. Here, we show how joint damping, in particular its anisotropy, directly affects task-space movements. Rather than using damping parameters to fit a posteriori task-space motions, we make the a priori hypothesis that damping is proportional to stiffness. This remarkably allows a postural-fitted model to also capture dynamic performance such as curvature and hysteresis of task-space trajectories during wrist pointing tasks, confirming and extending previous findings in literature. PMID:29249954

A pilot study to assess use of passive extension bias to facilitate finger movement for repetitive task practice after stroke.

PubMed

Iwamuro, B T; Fischer, H C; Kamper, D G

2011-01-01

The purpose of this study was to investigate whether active range of finger motion could be increased through the introduction of passive, external extension joint torques in stroke survivors. Five chronic stroke survivors with severe hand impairment resulting from hemiparesis took part in the study. Participants completed 2 experimental sessions in which hand movement and function were assessed. In one session, they wore a custom orthotic glove (X-Glove) that passively supplied extension torques to the joints of the fingers. In the second session, they performed the same tasks as in the other session, but without the glove. Outcome measures consisted of active range of motion, distance of the fingertip from the hand, selected tasks from the Graded Wolf Motor Function Test (GWMFT), and the Box and Blocks (BB) test. Primary results with and without the glove were compared using paired t tests with a Bonferroni correction. Active range of motion improved significantly by over 50%, from 4.4 cm to 6.7 cm, when the X-Glove was worn (P = .011). The distance of the fingertip from the metacarpophalangeal joint increased by an average of 2.2 cm for 4 of the subjects, although this change was not significant across all 5 subjects (P = .123). No significant differences were observed in the BB or GWMFT whether the X-Glove was worn or not. Introduction of passive extension torque can improve active range of motion for the fingers, even in chronic stroke survivors with substantial hand impairment. The increased range of motion would facilitate therapeutic training of the hand, potentially even in the home environment, although the bulk of the orthosis should be minimized to facilitate interactions with real objects.

Preliminary design of a simple passive toe exercise apparatus with a flexible metal hydride actuator for pressure ulcer prevention.

PubMed

Ino, Shuichi; Sato, Mitsuru; Hosono, Minako; Nakajima, Sawako; Yamashita, Kazuhiko; Izumi, Takashi

2010-01-01

In an aging society, social demands for home-based rehabilitation and assistive technologies by healthcare and welfare services are globally increasing. The progress of quality-of-life technologies and rehabilitation science is a very important and urgent issue for elderly and disabled individuals as well as for their caregivers. Thus, there is a substantial need to develop simple bedside apparatuses for both continuous exercise of joints and for power assistance for standing to prevent and manage disuse syndromes (e.g., pressure ulcers, joint contractures and muscular atrophy). Unfortunately, there are currently no commercially-available actuators compatible with the human requirements of flexibility, quietness, lightness and a high power-to-weight ratio. To fulfill the above demands, we have developed a novel actuation device using a metal hydride (MH) alloy and a laminate film, called the flexible MH actuator, as a human-friendly force generator for healthcare and welfare services. In this paper, we show the basic structure and characteristics of the flexible MH actuator used to create a passive exercise system for preventing disuse syndromes. To evaluate the efficiency of passive exercise for bedsore prevention, subcutaneous blood flow during passive exercise at common pressure-ulcer sites is measured by a laser blood flow meter. The force and range-of-motion angle required for a passive exercise apparatus is also examined with the help of a professional physical therapist. Based on these findings, a prototype of a passive exercise apparatus is fabricated using the flexible MH actuator technology, and its operation characteristics are preliminarily verified using a thermoelectric control system.

Aging scaled Brownian motion

NASA Astrophysics Data System (ADS)

Safdari, Hadiseh; Chechkin, Aleksei V.; Jafari, Gholamreza R.; Metzler, Ralf

2015-04-01

Scaled Brownian motion (SBM) is widely used to model anomalous diffusion of passive tracers in complex and biological systems. It is a highly nonstationary process governed by the Langevin equation for Brownian motion, however, with a power-law time dependence of the noise strength. Here we study the aging properties of SBM for both unconfined and confined motion. Specifically, we derive the ensemble and time averaged mean squared displacements and analyze their behavior in the regimes of weak, intermediate, and strong aging. A very rich behavior is revealed for confined aging SBM depending on different aging times and whether the process is sub- or superdiffusive. We demonstrate that the information on the aging factorizes with respect to the lag time and exhibits a functional form that is identical to the aging behavior of scale-free continuous time random walk processes. While SBM exhibits a disparity between ensemble and time averaged observables and is thus weakly nonergodic, strong aging is shown to effect a convergence of the ensemble and time averaged mean squared displacement. Finally, we derive the density of first passage times in the semi-infinite domain that features a crossover defined by the aging time.

Aging scaled Brownian motion.

PubMed

Safdari, Hadiseh; Chechkin, Aleksei V; Jafari, Gholamreza R; Metzler, Ralf

2015-04-01

Scaled Brownian motion (SBM) is widely used to model anomalous diffusion of passive tracers in complex and biological systems. It is a highly nonstationary process governed by the Langevin equation for Brownian motion, however, with a power-law time dependence of the noise strength. Here we study the aging properties of SBM for both unconfined and confined motion. Specifically, we derive the ensemble and time averaged mean squared displacements and analyze their behavior in the regimes of weak, intermediate, and strong aging. A very rich behavior is revealed for confined aging SBM depending on different aging times and whether the process is sub- or superdiffusive. We demonstrate that the information on the aging factorizes with respect to the lag time and exhibits a functional form that is identical to the aging behavior of scale-free continuous time random walk processes. While SBM exhibits a disparity between ensemble and time averaged observables and is thus weakly nonergodic, strong aging is shown to effect a convergence of the ensemble and time averaged mean squared displacement. Finally, we derive the density of first passage times in the semi-infinite domain that features a crossover defined by the aging time.

The Effect of Music Listening on Pain, Heart Rate Variability, and Range of Motion in Older Adults After Total Knee Replacement.

PubMed

Hsu, Chih-Chung; Chen, Su-Ru; Lee, Pi-Hsia; Lin, Pi-Chu

2017-12-01

The purpose of this study was to investigate the effects that listening and not listening to music had on pain relief, heart rate variability (HRV), and knee range of motion in total knee replacement (TKR) patients who underwent continuous passive motion (CPM) rehabilitation. We adopted a single-group quasi-experimental design. A sample of 49 TKR patients listened to music for 25 min during one session of CPM and no music during another session of CPM the same day for a total of 2 days. Results indicated that during CPM, patients exhibited a significant decrease in the pain level ( p < .05), an increase in the CPM knee flexion angle ( p < .05), a decrease in the low-frequency/high-frequency ratio (LF/HF) and normalized LF (nLF) of the HRV ( p < .01), and an increase in the normalized HF (nHF) and standard deviation of all normal-to-normal intervals (SDNN; p < .01) when listening to music compared with no music. This study demonstrated that listening to music can effectively decrease pain during CPM rehabilitation and improve the joint range of motion in patients who underwent TKR surgery.

Turning Passive Brownian Motion Into Active Motion

NASA Astrophysics Data System (ADS)

Sevilla, Francisco J.; VáSquez-Arzola, Alejandro; Puga-Cital, Enrique

We consider out-of-equilibrium phenomena, specifically, the pattern of motion of active particles. These particles absorb energy from the environment and transform it into self-locomotion, generally, through complex mechanisms. Though the out-of-equilibrium nature of on the motion of these systems is well recognized, is generally difficult to pinpoint how far from equilibrium these systems are. In this work we elucidate the out-of-equilibrium nature of non-interacting, trapped, active particles, whose pattern of motion is described by a run-and-tumble dynamics. We show that the stationary distributions of these run-and-tumble particles, moving under the effects of an external potential, is equivalent to the stationary distribution of non-interacting, passive Brownian particles moving in the same potential but in an inhomogeneous source of heat. The interest in this topic has recently regrown due to the experimental possibility to design man-made active particles that emulate the ones that exist in the biological realm. F.J.S kindly acknowledges support from Grant UNAM-DGAPA-PAPIIT-IN113114.

Susceptibility of cat and squirrel monkey to motion sickness induced by visual stimulation: Correlation with susceptibility to vestibular stimulation

NASA Technical Reports Server (NTRS)

Daunton, N. G.; Fox, R. A.; Crampton, G. H.

1984-01-01

Experiments in which the susceptibility of both cats and squirrel monkeys to motion sickness induced by visual stimulation are documented. In addition, it is shown that in both species those individual subjects most highly susceptible to sickness induced by passive motion are also those most likely to become motion sick from visual (optokinetic) stimulation alone.

Tertiary thrust systems and fluid flow beneath the Beaufort coastal plain (1002 area), Arctic National Wildlife Refuge, Alaska, U.S.A.

USGS Publications Warehouse

Potter, Christopher J.; Grow, John A.; Perry, William J.; Moore, Thomas E.; O'Sullivan, Paul B.; Phillips, Jeffrey D.; Saltus, Richard W.

2004-01-01

In the eastern part of the 1002 area, a northward-younging pattern of thin-skinned deformation is apparent. Converging patterns of Paleocene reflectors on the north flank of the Sabbath syncline indicate that the Aichilik high and the Sabbath syncline formed as a passive-roof duplex and piggyback basin, respectively, just behind the Paleocene deformation front. During the Eocene and possibly the Oligocene, thin-skinned thrusting advanced northward over the present location of the Niguanak high. A passive-roof duplex occupied the frontal part of this system. The Kingak and Hue shales exposed above the Niguanak high were transported into their present structural position during the Eocene to Oligocene motion on the long thrust ramps above the present south flank of the Niguanak high. Broad, basement-cored subsurface domes (Niguanak high and Aurora dome) formed near the deformation front in the Oligocene, deforming the overlying thin-skinned structures and feeding a new increment of displacement into thin-skinned structures directly to the north. Deformation continued through the Miocene above a detachment in the basement. Offshore seismicity and Holocene shortening documented by previous workers may indicate that contractional deformation continues to the present day.

Development of a CPM Machine for Injured Fingers.

PubMed

Fu, Yili; Zhang, Fuxiang; Ma, Xin; Meng, Qinggang

2005-01-01

Human fingers are easy to be injured. A CPM machine is a mechanism based on the rehabilitation theory of continuous passive motion (CPM). To develop a CPM machine for the clinic application in the rehabilitation of injured fingers is a significant task. Therefore, based on the theories of evidence based medicine (EBM) and CPM, we've developed a set of biomimetic mechanism after modeling the motions of fingers and analyzing its kinematics and dynamics analysis. We also design an embedded operating system based on ARM (a kind of 32-bit RISC microprocessor). The equipment can achieve the precise control of moving scope of fingers, finger's force and speed. It can serves as a rational checking method and a way of assessment for functional rehabilitation of human hands. Now, the first prototype has been finished and will start the clinical testing in Harbin Medical University shortly.

Intensive rehabilitative approach to eosinophilia myalgia syndrome associated with severe polyneuropathy.

PubMed

Draznin, E; Rosenberg, N L

1993-07-01

We report a case of the eosinophilia myalgia syndrome (EMS) with incapacitating myalgias, weakness secondary to a severe polyneuropathy, and contractures in all four extremities requiring aggressive rehabilitation treatment. A 55-year-old woman was admitted to a rehabilitation hospital 11 months after the onset of EMS. At that time, she had severe weakness secondary to peripheral neuropathy and painful contractures in all extremities and required high doses of narcotics for pain control. A continuous passive range of motion machine was used in order to maintain range of motion obtained during active exercise therapy. The patient showed functional improvement in basic mobility and ADL skills. She was withdrawn from narcotics and successfully learned pain management techniques. An aggressive rehabilitation approach in the treatment of EMS associated with peripheral neuropathy may improve functional outcome even when instituted late in the clinical course.

Coupling of active motion and advection shapes intracellular cargo transport.

PubMed

Khuc Trong, Philipp; Guck, Jochen; Goldstein, Raymond E

2012-07-13

Intracellular cargo transport can arise from passive diffusion, active motor-driven transport along cytoskeletal filament networks, and passive advection by fluid flows entrained by such cargo-motor motion. Active and advective transport are thus intrinsically coupled as related, yet different representations of the same underlying network structure. A reaction-advection-diffusion system is used here to show that this coupling affects the transport and localization of a passive tracer in a confined geometry. For sufficiently low diffusion, cargo localization to a target zone is optimized either by low reaction kinetics and decoupling of bound and unbound states, or by a mostly disordered cytoskeletal network with only weak directional bias. These generic results may help to rationalize subtle features of cytoskeletal networks, for example as observed for microtubules in fly oocytes.

Brownian Motion with Active Fluctuations

NASA Astrophysics Data System (ADS)

Romanczuk, Pawel; Schimansky-Geier, Lutz

2011-06-01

We study the effect of different types of fluctuation on the motion of self-propelled particles in two spatial dimensions. We distinguish between passive and active fluctuations. Passive fluctuations (e.g., thermal fluctuations) are independent of the orientation of the particle. In contrast, active ones point parallel or perpendicular to the time dependent orientation of the particle. We derive analytical expressions for the speed and velocity probability density for a generic model of active Brownian particles, which yields an increased probability of low speeds in the presence of active fluctuations in comparison to the case of purely passive fluctuations. As a consequence, we predict sharply peaked Cartesian velocity probability densities at the origin. Finally, we show that such a behavior may also occur in non-Gaussian active fluctuations and discuss briefly correlations of the fluctuating stochastic forces.

A real-time respiration position based passive breath gating equipment for gated radiotherapy: A preclinical evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu Weigang; Xu Anjie; Li Guichao

2012-03-15

Purpose: To develop a passive gating system incorporating with the real-time position management (RPM) system for the gated radiotherapy. Methods: Passive breath gating (PBG) equipment, which consists of a breath-hold valve, a controller mechanism, a mouthpiece kit, and a supporting frame, was designed. A commercial real-time positioning management system was implemented to synchronize the target motion and radiation delivery on a linear accelerator with the patient's breathing cycle. The respiratory related target motion was investigated by using the RPM system for correlating the external markers with the internal target motion while using PBG for passively blocking patient's breathing. Six patientsmore » were enrolled in the preclinical feasibility and efficiency study of the PBG system. Results: PBG equipment was designed and fabricated. The PBG can be manually triggered or released to block or unblock patient's breathing. A clinical workflow was outlined to integrate the PBG with the RPM system. After implementing the RPM based PBG system, the breath-hold period can be prolonged to 15-25 s and the treatment delivery efficiency for each field can be improved by 200%-400%. The results from the six patients showed that the diaphragm motion caused by respiration was reduced to less than 3 mm and the position of the diaphragm was reproducible for difference gating periods. Conclusions: A RPM based PBG system was developed and implemented. With the new gating system, the patient's breath-hold time can be extended and a significant improvement in the treatment delivery efficiency can also be achieved.« less

Ultrasensitive, passive and wearable sensors for monitoring human muscle motion and physiological signals.

PubMed

Cai, Feng; Yi, Changrui; Liu, Shichang; Wang, Yan; Liu, Lacheng; Liu, Xiaoqing; Xu, Xuming; Wang, Li

2016-03-15

Flexible sensors have attracted more and more attention as a fundamental part of anthropomorphic robot research, medical diagnosis and physical health monitoring. Here, we constructed an ultrasensitive and passive flexible sensor with the advantages of low cost, lightness and wearability, electric safety and reliability. The fundamental mechanism of the sensor is based on triboelectric effect inducing electrostatic charges on the surfaces between two different materials. Just like a plate capacitor, current will be generated while the distance or size of the parallel capacitors changes caused by the small mechanical disturbance upon it and therefore the output current/voltage will be produced. Typically, the passive sensor unambiguously monitors muscle motions including hand motion from stretch-clench-stretch, mouth motion from open-bite-open, blink and respiration. Moreover, this sensor records the details of the consecutive phases in a cardiac cycle of the apex cardiogram, and identify the peaks including percussion wave, tidal wave and diastolic wave of the radial pulse wave. To record subtle human physiological signals including radial pulsilogram and apex cardiogram with excellent signal/noise ratio, stability and reproducibility, the sensor shows great potential in the applications of medical diagnosis and daily health monitoring. Copyright © 2015 Elsevier B.V. All rights reserved.

Active Brownian particles with velocity-alignment and active fluctuations

NASA Astrophysics Data System (ADS)

Großmann, R.; Schimansky-Geier, L.; Romanczuk, P.

2012-07-01

We consider a model of active Brownian particles (ABPs) with velocity alignment in two spatial dimensions with passive and active fluctuations. Here, active fluctuations refers to purely non-equilibrium stochastic forces correlated with the heading of an individual active particle. In the simplest case studied here, they are assumed to be independent stochastic forces parallel (speed noise) and perpendicular (angular noise) to the velocity of the particle. On the other hand, passive fluctuations are defined by a noise vector independent of the direction of motion of a particle, and may account, for example, for thermal fluctuations. We derive a macroscopic description of the ABP gas with velocity-alignment interaction. Here, we start from the individual-based description in terms of stochastic differential equations (Langevin equations) and derive equations of motion for the coarse-grained kinetic variables (density, velocity and temperature) via a moment expansion of the corresponding probability density function. We focus here on the different impact of active and passive fluctuations on onset of collective motion and show how active fluctuations in the active Brownian dynamics can change the phase-transition behaviour of the system. In particular, we show that active angular fluctuations lead to an earlier breakdown of collective motion and to the emergence of a new bistable regime in the mean-field case.

The role of passive avian head stabilization in flapping flight

PubMed Central

Pete, Ashley E.; Kress, Daniel; Dimitrov, Marina A.; Lentink, David

2015-01-01

Birds improve vision by stabilizing head position relative to their surroundings, while their body is forced up and down during flapping flight. Stabilization is facilitated by compensatory motion of the sophisticated avian head–neck system. While relative head motion has been studied in stationary and walking birds, little is known about how birds accomplish head stabilization during flapping flight. To unravel this, we approximate the avian neck with a linear mass–spring–damper system for vertical displacements, analogous to proven head stabilization models for walking humans. We corroborate the model's dimensionless natural frequency and damping ratios from high-speed video recordings of whooper swans (Cygnus cygnus) flying over a lake. The data show that flap-induced body oscillations can be passively attenuated through the neck. We find that the passive model robustly attenuates large body oscillations, even in response to head mass and gust perturbations. Our proof of principle shows that bird-inspired drones with flapping wings could record better images with a swan-inspired passive camera suspension. PMID:26311316

26 CFR 1.469-3T - Passive activity credit (temporary).

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 6 2011-04-01 2011-04-01 false Passive activity credit (temporary). 1.469-3T... TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3T Passive activity credit (temporary). (a) Computation of passive activity credit. The taxpayer's passive activity...

Associations of passive muscle stiffness, muscle stretch tolerance, and muscle slack angle with range of motion: individual and sex differences.

PubMed

Miyamoto, Naokazu; Hirata, Kosuke; Miyamoto-Mikami, Eri; Yasuda, Osamu; Kanehisa, Hiroaki

2018-05-29

Joint range of motion (ROM) is an important parameter for athletic performance and muscular injury risk. Nonetheless, a complete description of muscular factors influencing ROM among individuals and between men and women is lacking. We examined whether passive muscle stiffness (evaluated by angle-specific muscle shear modulus), tolerance to muscle stretch (evaluated by muscle shear modulus at end-ROM), and muscle slack angle of the triceps surae are associated with the individual variability and sex difference in dorsiflexion ROM, using ultrasound shear wave elastography. For men, ROM was negatively correlated to passive muscle stiffness of the medial and lateral gastrocnemius in a tensioned state and positively to tolerance to muscle stretch in the medial gastrocnemius. For women, ROM was only positively correlated to tolerance to muscle stretch in all muscles but not correlated to passive muscle stiffness. Muscle slack angle was not correlated to ROM in men and women. Significant sex differences were observed only for dorsiflexion ROM and passive muscle stiffness in a tensioned state. These findings suggest that muscular factors associated with ROM are different between men and women. Furthermore, the sex difference in dorsiflexion ROM might be attributed partly to that in passive muscle stiffness of plantar flexors.

Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to physiotherapy, after total knee arthroplasty

PubMed Central

Lenssen, Ton AF; van Steyn, Mike JA; Crijns, Yvonne HF; Waltjé, Eddie MH; Roox, George M; Geesink, Ruud JT; Brandt, Piet A van den; De Bie, Rob A

2008-01-01

Background Adequate and intensive rehabilitation is an important requirement for successful total knee arthroplasty. Although research suggests that Continuous Passive Motion (CPM) should be implemented in the first rehabilitation phase after surgery, there is substantial debate about the duration of each session and the total period of CPM application. A Cochrane review on this topic concluded that short-term use of CPM leads to greater short-term range of motion. It also suggested, however, that future research should concentrate on the treatment period during which CPM should be administered. Methods In a randomised controlled trial we investigated the effectiveness of prolonged CPM use in the home situation as an adjunct to standardised PT. Efficacy was assessed in terms of faster improvements in range of motion (RoM) and functional recovery, measured at the end of the active treatment period, 17 days after surgery. Sixty patients with knee osteoarthritis undergoing TKA and experiencing early postoperative flexion impairment were randomised over two treatment groups. The experimental group received CPM + PT for 17 consecutive days after surgery, whereas the usual care group received the same treatment during the in-hospital phase (i.e. about four days), followed by PT alone (usual care) in the first two weeks after hospital discharge. From 18 days to three months after surgery, both groups received standardised PT. The primary focus of rehabilitation was functional recovery (e.g. ambulation) and regaining RoM in the knee. Results Prolonged use of CPM slightly improved short-term RoM in patients with limited RoM at the time of discharge after total knee arthroplasty when added to a semi-standard PT programme. Assessment at 6 weeks and three months after surgery found no long-term effects of this intervention Neither did we detect functional benefits of the improved RoM at any of the outcome assessments. Conclusion Although results indicate that prolonged CPM use might have a small short-term effect on RoM, routine use of prolonged CPM in patients with limited RoM at hospital discharge should be reconsidered, since neither long-term effects nor transfer to better functional performance was detected. Trial Registration ISRCTN85759656 PMID:18442423

Nonsurgical treatment to regain hip abduction motion in Perthes disease: a retrospective review.

PubMed

Carney, Brian T; Minter, Christin L

2004-05-01

The purpose of this study was to document the ability of a nonsurgical program to improve restricted passive hip abduction in children with Perthes disease. Containment as a form of treatment was recommended if passive hip abduction of 30 degrees or more could be achieved. Medical records and radiographs were retrospectively reviewed for 74 children. Age at admission and onset, side, length of stay, and measurement of passive hip abduction at admission/discharge were recorded. The average increase in abduction with the hip extended was 13 degrees. Forty-two children achieved 30 degrees or more of abduction with the hip extended. Average length of stay was 13 days. Management of restricted abduction in an inpatient setting can allow consideration of containment in 61% of children previously not thought to have the required motion.

Active and Passive Microrheology: Theory and Simulation

NASA Astrophysics Data System (ADS)

Zia, Roseanna N.

2018-01-01

Microrheological study of complex fluids traces its roots to the work of the botanist Robert Brown in the early nineteenth century. Indeed, passive microrheology and Brownian motion are one and the same. Once thought to reveal a fundamental life force, the phenomenon was ultimately leveraged by Einstein in proof of the atomic nature of matter ( Haw 2006 ). His work simultaneously paved the way for modern-day passive microrheology by connecting observable particle motion—diffusion—to solvent properties—the viscosity—via the well-known Stokes-Einstein relation. Advances in microscopy techniques in the last two decades have prompted extensions of the original model to generalized forms for passive probing of complex fluids. In the last decade, active microrheology has emerged as a means by which to interrogate the nonequilibrium behavior of complex fluids, in particular, the non-Newtonian rheology of dynamically heterogeneous and microscopically small systems. Here we review theoretical and computational approaches and advances in both passive and active microrheology, with a focus on the extent to which these techniques preserve the connection between single-particle motion and flow properties, as well as the rather surprising recovery of non-Newtonian flow behavior observed in bulk rheology.

Hip and upper extremity kinematics in youth baseball pitchers.

PubMed

Holt, Taylor; Oliver, Gretchen D

2016-01-01

The purpose of this study was to examine the relationship between dynamic hip rotational range of motion and upper extremity kinematics during baseball pitching. Thirty-one youth baseball pitchers (10.87 ± 0.92 years; 150.03 ± 5.48 cm; 44.83 ± 8.04 kg) participated. A strong correlation was found between stance hip rotation and scapular upward rotation at maximum shoulder external rotation (r = 0.531, P = 0.002) and at ball release (r = 0.536, P = 0.002). No statistically significant correlations were found between dynamic hip rotational range of motion and passive hip range of motion. Hip range of motion deficits can constrain pelvis rotation and limit energy generation in the lower extremities. Shoulder pathomechanics can then develop as greater responsibility is placed on the shoulder to generate the energy lost from the proximal segments, increasing risk of upper extremity injury. Additionally, it appears that passive seated measurements of hip range of motion may not accurately reflect the dynamic range of motion of the hips through the progression of the pitch cycle.

SHADE: A Shape-Memory-Activated Device Promoting Ankle Dorsiflexion

NASA Astrophysics Data System (ADS)

Pittaccio, S.; Viscuso, S.; Rossini, M.; Magoni, L.; Pirovano, S.; Villa, E.; Besseghini, S.; Molteni, F.

2009-08-01

Acute post-stroke rehabilitation protocols include passive mobilization as a means to prevent contractures. A device (SHADE) that provides repetitive passive motion to a flaccid ankle by using shape memory alloy actuators could be of great help in providing this treatment. A suitable actuator was designed as a cartridge of approximately 150 × 20 × 15 mm, containing 2.5 m of 0.25 mm diameter NiTi wire. This actuator was activated by Joule’s effect employing a 7 s current input at 0.7 A, which provided 10 N through 76 mm displacement. Cooling and reset by natural convection took 30 s. A prototype of SHADE was assembled with two thermoplastic shells hinged together at the ankle and strapped on the shin and foot. Two actuators were fixed on the upper shell while an inextensible thread connected each NiTi wire to the foot shell. The passive ankle motion (passive range of motion, PROM) generated by SHADE was evaluated optoelectronically on three flaccid patients (58 ± 5 years old); acceptability was assessed by a questionnaire presented to further three flaccid patients (44 ± 11.5 years old) who used SHADE for 5 days, 30 min a day. SHADE was well accepted by all patients, produced good PROM, and caused no pain. The results prove that suitable limb mobilization can be produced by SMA actuators.

Sensor Management for Tactical Surveillance Operations

DTIC Science & Technology

2007-11-01

active and passive sonar for submarine and tor- pedo detection, and mine avoidance. [range, bearing] range 1.8 km to 55 km Active or Passive AN/SLQ-501...finding (DF) unit [bearing, classification] maximum range 1100 km Passive Cameras (day- light/ night- vision) ( video & still) Record optical and...infrared still images or motion video of events for near-real time assessment or long term analysis and archiving. Range is limited by the image resolution

[Duration and temporality].

PubMed

Fouks, L; Guibert, S; Cardon; Montot

1990-01-01

The notion of temporality in living is in perpetual motion between passive temporality and creative conscience. Human existence is not purely immanent, a flow of transcedence continually runs through it. Melancholia is a lose of creativity accompanied by a feeling that time as lived has stopped, time being lived as a new mode of space. Maniac temporality is an improductive and unsociable furious flight toward. The melancholic feeling out of time is crushed by the problematic of alterity, sin and eternity. The maniac lives an imaginary and deceptive problematic. The ambivalent ideal of the schizophrenic is both a return to biological life as well as a fascination by formal thought.

Passivity-based sliding mode control for a polytopic stochastic differential inclusion system.

PubMed

Liu, Leipo; Fu, Zhumu; Song, Xiaona

2013-11-01

Passivity-based sliding mode control for a polytopic stochastic differential inclusion (PSDI) system is considered. A control law is designed such that the reachability of sliding motion is guaranteed. Moreover, sufficient conditions for mean square asymptotic stability and passivity of sliding mode dynamics are obtained by linear matrix inequalities (LMIs). Finally, two examples are given to illustrate the effectiveness of the proposed method. © 2013 ISA. Published by ISA. All rights reserved.

INS integrated motion analysis for autonomous vehicle navigation

NASA Technical Reports Server (NTRS)

Roberts, Barry; Bazakos, Mike

1991-01-01

The use of inertial navigation system (INS) measurements to enhance the quality and robustness of motion analysis techniques used for obstacle detection is discussed with particular reference to autonomous vehicle navigation. The approach to obstacle detection used here employs motion analysis of imagery generated by a passive sensor. Motion analysis of imagery obtained during vehicle travel is used to generate range measurements to points within the field of view of the sensor, which can then be used to provide obstacle detection. Results obtained with an INS integrated motion analysis approach are reviewed.

Ross sea ice motion, area flux, and deformation

NASA Technical Reports Server (NTRS)

kwok, Ron

2005-01-01

The sea ice motion, area export, and deformation of the Ross Sea ice cover are examined with satellite passive microwave and RADARSAT observations. The record of high-resolution synthetic aperture radar (SAR) data, from 1998 and 2000, allows the estimation of the variability of ice deformation at the small scale (10 km) and to assess the quality of the longer record of passive microwave ice motion. Daily and subdaily deformation fields and RADARSAT imagery highlight the variability of motion and deformation in the Ross Sea. With the passive microwave ice motion, the area export at a flux gate positioned between Cape Adare and Land Bay is estimated. Between 1992 and 2003, a positive trend can be seen in the winter (March-November) ice area flux that has a mean of 990 x 103 km2 and ranges from a low of 600 x 103 km2 in 1992 to a peak of 1600 x 103 km2 in 2001. In the mean, the southern Ross Sea produces almost twice its own area of sea ice during the winter. Cross-gate sea level pressure (SLP) gradients explain 60% of the variance in the ice area flux. A positive trend in this gradient, from reanalysis products, suggests a 'spinup' of the Ross Sea Gyre over the past 12 yr. In both the NCEP-NCAR and ERA-40 surface pressure fields, longer-term trends in this gradient and mean SLP between 1979 and 2002 are explored along with positive anomalies in the monthly cross-gate SLP gradient associated with the positive phase of the Southern Hemisphere annular mode and the extrapolar Southern Oscillation.

Statistics of the Vestibular Input Experienced during Natural Self-Motion: Implications for Neural Processing

PubMed Central

Carriot, Jérome; Jamali, Mohsen; Chacron, Maurice J.

2014-01-01

It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/fα), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life. PMID:24920638

The Neural Correlates of Inhibiting Pursuit to Smoothly Moving Targets

ERIC Educational Resources Information Center

Burke, Melanie Rose; Barnes, Graham R.

2011-01-01

A previous study has shown that actively pursuing a moving target provides a predictive motor advantage when compared with passive observation of the moving target while keeping the eyes still [Burke, M. R., & Barnes, G. R. Anticipatory eye movements evoked after active following versus passive observation of a predictable motion stimulus. "Brain…

Swimming invariant manifolds and the motion of bacteria in a fluid flow

NASA Astrophysics Data System (ADS)

Yoest, Helena; Mitchell, Kevin; Solomon, Tom

2017-11-01

We present experiments on the motion of both wild-type and smooth-swimming bacillus subtilis in a hyperbolic, microfluidic fluid flow. Passive invariant manifolds crossing the fixed point in the flow act as barriers that block inert tracers in the flow. Self-propelled tracers can cross these passive manifolds, but are blocked by and attracted to swimming invariant manifolds (SWIMs) that split from the passive manifolds with larger and larger non-dimensional swimming speed v0 ≡V0 / U , where V0 is the swimming speed in the absence of a flow and U is a characteristic flos speed. We present the theory that predicts these SWIMs for smooth-swimming tracers, along with experiments that we are conducting to test these theories. We also discuss potential effects of rheotaxis and chemotaxis on the phenomena. Supported by NSF Grant DMR-1361881.

26 CFR 1.469-3 - Passive activity credit.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 6 2011-04-01 2011-04-01 false Passive activity credit. 1.469-3 Section 1.469-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3 Passive activity credit. (a...

Effects of robot-guided passive stretching and active movement training of ankle and mobility impairments in stroke.

PubMed

Waldman, Genna; Yang, Chung-Yong; Ren, Yupeng; Liu, Lin; Guo, Xin; Harvey, Richard L; Roth, Elliot J; Zhang, Li-Qun

2013-01-01

To investigate the effects of controlled passive stretching and active movement training using a portable rehabilitation robot on stroke survivors with ankle and mobility impairment. Twenty-four patients at least 3 months post stroke were assigned to receive 6 week training using the portable robot in a research laboratory (robot group) or an instructed exercise program at home (control group). All patients underwent clinical and biomechanical evaluations in the laboratory at pre-evaluation, post-evaluation, and 6-week follow-up. Subjects in the robot group improved significantly more than that in the control group in reduction in spasticity measured by modified Ashworth scale, mobility by Stroke Rehabilitation Assessment of Movement (STREAM), the balance by Berg balance score, dorsiflexion passive range of motion, dorsiflexion strength, and load bearing on the affected limb during gait after 6-week training. Both groups improved in the STREAM, dorsiflexion active range of motion and dorsiflexor strength after the training, which were retained in the follow-up evaluation. Robot-assisted passive stretching and active movement training is effective in improving motor function and mobility post stroke.

Exploring the extent and function of higher-order auditory cortex in rhesus monkeys.

PubMed

Poremba, Amy; Mishkin, Mortimer

2007-07-01

Just as cortical visual processing continues far beyond the boundaries of early visual areas, so too does cortical auditory processing continue far beyond the limits of early auditory areas. In passively listening rhesus monkeys examined with metabolic mapping techniques, cortical areas reactive to auditory stimulation were found to include the entire length of the superior temporal gyrus (STG) as well as several other regions within the temporal, parietal, and frontal lobes. Comparison of these widespread activations with those from an analogous study in vision supports the notion that audition, like vision, is served by several cortical processing streams, each specialized for analyzing a different aspect of sensory input, such as stimulus quality, location, or motion. Exploration with different classes of acoustic stimuli demonstrated that most portions of STG show greater activation on the right than on the left regardless of stimulus class. However, there is a striking shift to left-hemisphere "dominance" during passive listening to species-specific vocalizations, though this reverse asymmetry is observed only in the region of temporal pole. The mechanism for this left temporal pole "dominance" appears to be suppression of the right temporal pole by the left hemisphere, as demonstrated by a comparison of the results in normal monkeys with those in split-brain monkeys.

Exploring the extent and function of higher-order auditory cortex in rhesus monkeys

PubMed Central

Mishkin, Mortimer

2009-01-01

Just as cortical visual processing continues far beyond the boundaries of early visual areas, so too does cortical auditory processing continue far beyond the limits of early auditory areas. In passively listening rhesus monkeys examined with metabolic mapping techniques, cortical areas reactive to auditory stimulation were found to include the entire length of the superior temporal gyrus (STG) as well as several other regions within the temporal, parietal, and frontal lobes. Comparison of these widespread activations with those from an analogous study in vision supports the notion that audition, like vision, is served by several cortical processing streams, each specialized for analyzing a different aspect of sensory input, such as stimulus quality, location, or motion. Exploration with different classes of acoustic stimuli demonstrated that most portions of STG show greater activation on the right than on the left regardless of stimulus class. However, there is a striking shift to left hemisphere “dominance” during passive listening to species-specific vocalizations, though this reverse asymmetry is observed only in the region of temporal pole. The mechanism for this left temporal pole “dominance” appears to be suppression of the right temporal pole by the left hemisphere, as demonstrated by a comparison of the results in normal monkeys with those in split-brain monkeys. PMID:17321703

PRISM: A DATA-DRIVEN PLATFORM FOR MONITORING MENTAL HEALTH

PubMed Central

KAMDAR, MAULIK R.; WU, MICHELLE J.

2018-01-01

Neuropsychiatric disorders are the leading cause of disability worldwide and there is no gold standard currently available for the measurement of mental health. This issue is exacerbated by the fact that the information physicians use to diagnose these disorders is episodic and often subjective. Current methods to monitor mental health involve the use of subjective DSM-5 guidelines, and advances in EEG and video monitoring technologies have not been widely adopted due to invasiveness and inconvenience. Wearable technologies have surfaced as a ubiquitous and unobtrusive method for providing continuous, quantitative data about a patient. Here, we introduce PRISM — Passive, Real-time Information for Sensing Mental Health. This platform integrates motion, light and heart rate data from a smart watch application with user interactions and text insights from a web application. We have demonstrated a proof of concept by collecting preliminary data through a pilot study of 13 subjects. We have engineered appropriate features and applied both unsupervised and supervised learning to develop models that can recapitulate user-reported ratings of their emotional state. This demonstrates that the data has the potential to be useful for evaluating mental health. This platform will allow us to leverage continuous streams of passive data for early and accurate diagnosis as well as constant monitoring of patients suffering from mental disorders. PMID:26776198

Kinesthetic deficit in children with developmental coordination disorder.

PubMed

Li, Kuan-yi; Su, Wei-jen; Fu, Hsuan-wei; Pickett, Kristen A

2015-03-01

The aim of this study was to measure and compare kinesthetic sensitivity in children with developmental coordination disorder (DCD) and typically developing (TD) children between 6 and 11 years old. 30 children with DCD aged 6 to 11 years (5 in each age group) and 30 TD children participated in the study. Participants placed their forearms on a passive motion apparatus which extended the elbow joint at constant velocities between 0.15 and 1.35°s(-1). Participants were required to concentrate on detection of passive arm motion and press a trigger held in their left hand once they sensed it. The detection time was measured for each trial. The DCD group was significantly less sensitive in detection of passive motion than TD children. Further analysis of individual age groups revealed that kinesthetic sensitivity was worse in DCD than TD children for age groups beyond six years of age. Our findings suggested that individual with DCD lag behind their TD counterparts in kinesthetic sensitivity. Between the ages of 7 and 11 years the difference between groups is quantifiable and significant with 11 year old children with DCD performing similar to 7 year old TD children. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mechanical risk of rotator cuff repair failure during passive movements: A simulation-based study.

PubMed

Haering, Diane; Blache, Yoann; Raison, Maxime; Begon, Mickael

2015-12-01

Despite improvements in rotator cuff surgery techniques, re-tear rate remains above 20% and increases with tear severity. Mechanical stresses to failure of repaired tendons have been reported. While optimal immobilization postures were proposed to minimize this stress, post-operative rehabilitation protocols have never been assessed with respect to these values. Purpose was to use musculoskeletal simulation to predict when the stress in repaired tendons exceeds safety limits during passive movements. Hence, guidelines could be provided towards safer post-operative exercises. Sixteen healthy participants volunteered in passive three-dimensional shoulder range-of-motion and passive rehabilitation exercises assessment. Stress in all rotator cuff tendons was predicted during each movement by means of a musculoskeletal model using simulations with different type and size of tears. Safety stress thresholds were defined based on repaired tendon loads to failure reported in the literature and used to discriminate safe from unsafe ranges-of-motion. Increased tear size and multiple tendons tear decreased safe range-of-motion. Mostly, glenohumeral elevations below 38°, above 65°, or performed with the arm held in internal rotation cause excessive stresses in most types and sizes of injury during abduction, scaption or flexion. Larger safe amplitudes of elevation are found in scapular plane for supraspinatus alone, supraspinatus plus infraspinatus, and supraspinatus plus subscapularis tears. This study reinforces that passive early rehabilitation exercises could contribute to re-tear due to excessive stresses. Recommendations arising from this study, for instance to keep the arm externally rotated during elevation in case of supraspinatus or supraspinatus plus infraspinatus tear, could help prevent re-tear. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

A mathematical model of an active control landing gear for load control during impact and roll-out

NASA Technical Reports Server (NTRS)

Mcgehee, J. R.; Carden, H. D.

1976-01-01

A mathematical model of an active control landing gear (ACOLAG) was developed and programmed for operation on a digital computer. The mathematical model includes theoretical subsonic aerodynamics; first-mode wing bending and torsional characteristics; oleo-pneumatic shock strut with fit and binding friction; closed-loop, series-hydraulic control; empirical tire force-deflection characteristics; antiskid braking; and sinusoidal or random runway roughness. The mathematical model was used to compute the loads and motions for a simulated vertical drop test and a simulated landing impact of a conventional (passive) main landing gear designed for a 2268-kg (5000-lbm) class airplane. Computations were also made for a simply modified version of the passive gear including a series-hydraulic active control system. Comparison of computed results for the passive gear with experimental data shows that the active control landing gear analysis is valid for predicting the loads and motions of an airplane during a symmetrical landing. Computed results for the series-hydraulic active control in conjunction with the simply modified passive gear show that 20- to 30-percent reductions in wing force, relative to those occurring with the modified passive gear, can be obtained during the impact phase of the landing. These reductions in wing force could result in substantial increases in fatigue life of the structure.

Emergence of the Green’s Functions from Noise and Passive Acoustic Remote Sensing of Ocean Dynamics

DTIC Science & Technology

2009-09-30

Acoustic Remote Sensing of Ocean Dynamics Oleg A. Godin CIRES/Univ. of Colorado and NOAA/OAR/Earth System Research Lab., R/PSD99, 325 Broadway...characterization of a time-varying ocean where ambient acoustic noise is utilized as a probing signal. • To develop a passive remote sensing technique for...inapplicable. 3. To quantify degradation of performance of passive remote sensing techniques due to ocean surface motion and other variations of underwater

Motorized CPM/CAM physiotherapy device with sliding-mode Fuzzy Neural Network control loop.

PubMed

Ho, Hung-Jung; Chen, Tien-Chi

2009-11-01

Continuous passive motion (CPM) and controllable active motion (CAM) physiotherapy devices promote rehabilitation of damaged joints. This paper presents a computerized CPM/CAM system that obviates the need for mechanical resistance devices such as springs. The system is controlled by a computer which performs sliding-mode Fuzzy Neural Network (FNN) calculations online. CAM-type resistance force is generated by the active performance of an electric motor which is controlled so as to oppose the motion of the patient's leg. A force sensor under the patient's foot on the device pedal provides data for feedback in a sliding-mode FNN control loop built around the motor. Via an active impedance control feedback system, the controller drives the motor to behave similarly to a damped spring by generating and controlling the amplitude and direction of the pedal force in relation to the patient's leg. Experiments demonstrate the high sensitivity and speed of the device. The PC-based feedback nature of the control loop means that sophisticated auto-adaptable CPM/CAM custom-designed physiotherapy becomes possible. The computer base also allows extensive data recording, data analysis and network-connected remote patient monitoring.

Modelling three-dimensional cochlear micromechanics within the guinea pig organ of Corti

NASA Astrophysics Data System (ADS)

Ni, Guangjian; Elliott, Stephen J.

2018-05-01

The active amplification process in the mammalian cochlea depends on a complex interaction between cells within the organ of Corti. A three-dimensional (3D) model was developed using the finite element method based on anatomy for the apical end in the guinea pig cochlea, which is comprised of 3D discrete hair cells, 3D continuous membranes and fluid. The basilar membrane, tectorial membrane and the reticular lamina are modelled with orthotropic materials. The Y-shape structures formed by the outer hair cell (OHC), the Deiters' cell and Deiters' cell phalangeal process are also included to account for the structural longitudinal coupling. The motion within the organ of Corti was first simulated in response to a pressure difference loading on the basilar membrane, in order to calculate the passive vibration pattern. Then, the outer hair cells somatic electromotility was implemented by applying a voltage across the OHC walls to investigate its contribution to membranes motion.

The Stormy Life of Galaxy Clusters

NASA Astrophysics Data System (ADS)

Rudnick, Lawrence

2018-01-01

Galaxy clusters, the largest gravitationally bound structures, hold the full history of their baryonic evolution, serve as important cosmological tools and allow us to probe unique physical regimes in their diffuse plasmas. With characteristic dynamical timescales of 107-109 years, these diffuse thermal and relativistic media continue to evolve, as dark matter drives major mergers and more gentle continuing accretion. The history of this assembly is encoded in the plasmas, and a wide range of observational and theoretical investigations are aimed at decoding their signatures. X-ray temperature and density variations, low Mach number shocks, and "cold front" discontinuities all illuminate clusters' continued evolution. Radio structures and spectra are passive indicators of merger shocks, while radio galaxy distortions reveal the complex motions in the intracluster medium. Deep in cluster cores, AGNs associated with brightest cluster galaxies provide ongoing energy, and perhaps even stabilize the intracluster medium. In this talk, we will recount this evolving picture of the stormy ICM, and suggest areas of likely advance in the coming years.

Does immobilization after arthroscopic rotator cuff repair increase tendon healing? A systematic review and meta-analysis.

PubMed

Shen, Chong; Tang, Zhi-Hong; Hu, Jun-Zu; Zou, Guo-Yao; Xiao, Rong-Chi; Yan, Dong-Xue

2014-09-01

To determine whether immobilization after arthroscopic rotator cuff repair improved tendon healing compared with early passive motion. A systematic electronic literature search was conducted to identify randomized controlled trials (RCTs) comparing early passive motion with immobilization after arthroscopic rotator cuff repair. The primary outcome assessed was tendon healing in the repaired cuff. Secondary outcome measures were range of motion (ROM) and American Shoulder and Elbow Surgeons (ASES) shoulder scale, Simple Shoulder Test (SST), Constant, and visual analog scale (VAS) for pain scores. Pooled analyses were performed using a random effects model to obtain summary estimates of treatment effect with 95% confidence intervals. Heterogeneity among included studies was quantified. Three RCTs examining 265 patients were included. Meta-analysis revealed no significant difference in tendon healing in the repaired cuff between the early-motion and immobilization groups. A significant difference in external rotation at 6 months postoperatively favored early motion over immobilization, but no significant difference was observed at 1 year postoperatively. In one study, Constant scores were slightly higher in the early-motion group than in the immobilization group. Two studies found no significant difference in ASES, SST, or VAS score between groups. We found no evidence that immobilization after arthroscopic rotator cuff repair was superior to early-motion rehabilitation in terms of tendon healing or clinical outcome. Patients in the early-motion group may recover ROM more rapidly. Level II; systematic review of levels I and II studies.

Parallax-sensitive remapping of visual space in occipito-parietal alpha-band activity during whole-body motion

PubMed Central

Selen, L. P. J.; Medendorp, W. P.

2014-01-01

Despite the constantly changing retinal image due to eye, head, and body movements, we are able to maintain a stable representation of the visual environment. Various studies on retinal image shifts caused by saccades have suggested that occipital and parietal areas correct for these perturbations by a gaze-centered remapping of the neural image. However, such a uniform, rotational, remapping mechanism cannot work during translations when objects shift on the retina in a more complex, depth-dependent fashion due to motion parallax. Here we tested whether the brain's activity patterns show parallax-sensitive remapping of remembered visual space during whole-body motion. Under continuous recording of electroencephalography (EEG), we passively translated human subjects while they had to remember the location of a world-fixed visual target, briefly presented in front of or behind the eyes' fixation point prior to the motion. Using a psychometric approach we assessed the quality of the memory update, which had to be made based on vestibular feedback and other extraretinal motion cues. All subjects showed a variable amount of parallax-sensitive updating errors, i.e., the direction of the errors depended on the depth of the target relative to fixation. The EEG recordings show a neural correlate of this parallax-sensitive remapping in the alpha-band power at occipito-parietal electrodes. At parietal electrodes, the strength of these alpha-band modulations correlated significantly with updating performance. These results suggest that alpha-band oscillatory activity reflects the time-varying updating of gaze-centered spatial information during parallax-sensitive remapping during whole-body motion. PMID:25505108

Knee flexion contractures in institutionalized elderly: prevalence, severity, stability, and related variables.

PubMed

Mollinger, L A; Steffen, T M

1993-07-01

The purpose of this study was to document the prevalence, severity, and progression of knee flexion contractures (KFCs) in a population of institutionalized elderly and to identify relationships between knee extension and other variables. The subjects were 112 nursing home residents who exhibited a broad range of ambulation and cognitive function abilities. Data were collected initially (T1) and after a 10-month period (T2). Only 25% of the population had extension in the 0- to 5-degree (lacking full extension) range bilaterally at T1 and T2, leaving the majority of subjects with some degree of unilateral KFC. Most of the subjects with a KFC greater than 20 degrees were nonambulatory and had a significantly higher occurrence of resistance to motion than did nonambulators with a KFC of less than 20 degrees. Knee extension measurements did not change in most subjects between T1 and T2. The knees that did show a change in KFC (either an increase or a decrease) had a significantly higher occurrence of resistance to passive motion than did other knees. Compared with the subjects who gained extension, the subjects who lost extension over the study period more frequently had minimal KFC at T1, were ambulatory at T1, showed a regression in ambulation at T2, and developed resistance to motion at T2. The data confirmed significant positive correlations between degree of KFC and presence of resistance to passive knee motion, cognitive impairment, impaired ambulation, and presence of knee pain. Physical therapy assessment and intervention may be appropriate in nonambulatory nursing home residents with resistance to passive motion, residents with KFC approaching 20 degrees, and ambulatory residents with minimal KFC who develop resistance and begin to regress in ambulation. Several areas for future study are suggested.

Statistics of the vestibular input experienced during natural self-motion: implications for neural processing.

PubMed

Carriot, Jérome; Jamali, Mohsen; Chacron, Maurice J; Cullen, Kathleen E

2014-06-11

It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/f(α)), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life. Copyright © 2014 the authors 0270-6474/14/348347-11$15.00/0.

Addition of Passive Dynamics to a Flapping Airfoil to Improve Performance

NASA Astrophysics Data System (ADS)

Asselin, Daniel; Young, Jay; Williamson, C. H. K.

2017-11-01

Animals which fly or swim typically employ flapping motions of their wings and fins in order to produce thrust and to maneuver. Small, unmanned vehicles might also exploit such motions and are of considerable interest for the purposes of surveillance, environmental monitoring, and search and rescue. Flapping refers to a combination of pitch and heave and has been shown to provide good thrust and efficiency (Read, et al. 2003) when both axes are independently controlled (an Active-Active system). In this study, we examine the performance of an airfoil actuated only in the heave direction but allowed to pitch passively under the control of a torsion spring (an Active-Passive system). The presence of the spring is simulated in software using a force-feedback control system called Cyber-Physical Fluid Dynamics, or CPFD (Mackowski & Williamson 2011, 2015, 2016). Adding passive pitch to active heave provides significantly improved thrust and efficiency compared with heaving alone, especially when the torsion spring stiffness is selected so that the system operates near resonance (in an Active-Passive system). In many cases, values of thrust and efficiency are comparable to or better than those obtained with two actively controlled degrees of freedom. By using carefully-designed passive dynamics in the pitch direction, we can eliminate one of the two actuators, saving cost, complexity, and weight, while maintaining performance. This work was supported by the Air Force Office of Scientific Research Grant No. FA9550-15-1-0243, monitored by Dr. Douglas Smith.

Restoration of Full Shoulder Range of Motion After Application of the Fascial Distortion Model.

PubMed

Boucher, Joshua D; Figueroa, Jose

2018-05-01

Decreased active and passive range of motion (ROM) accompanied by pain in the shoulder is a common presentation for patients with frozen shoulder, and it can be difficult to restore normal function. Through the fascial distortion model, physicians can apply a manual technique to rapidly and effectively increase ROM and decrease pain. A 28-year-old man presented 18 months after sustaining a shoulder hyperextension injury. On active and passive ROM examination, he had approximately 90° of shoulder abduction and moderately reduced internal rotation associated with 8/10 pain. After 2 applications of the fascial distortion model, his shoulder restored to full abduction and internal rotation with no pain.

A geophone wireless sensor network for investigating glacier stick-slip motion

NASA Astrophysics Data System (ADS)

Martinez, Kirk; Hart, Jane K.; Basford, Philip J.; Bragg, Graeme M.; Ward, Tyler; Young, David S.

2017-08-01

We have developed an innovative passive borehole geophone system, as part of a wireless environmental sensor network to investigate glacier stick-slip motion. The new geophone nodes use an ARM Cortex-M3 processor with a low power design capable of running on battery power while embedded in the ice. Only data from seismic events was stored, held temporarily on a micro-SD card until they were retrieved by systems on the glacier surface which are connected to the internet. The sampling rates, detection and filtering levels were determined from a field trial using a standard commercial passive seismic system. The new system was installed on the Skalafellsjökull glacier in Iceland and provided encouraging results. The results showed that there was a relationship between surface melt water production and seismic event (ice quakes), and these occurred on a pattern related to the glacier surface melt-water controlled velocity changes (stick-slip motion). Three types of seismic events were identified, which were interpreted to reflect a pattern of till deformation (Type A), basal sliding (Type B) and hydraulic transience (Type C) associated with stick-slip motion.

The clinical effect of rehabilitation following arthroscopic rotator cuff repair: A meta-analysis of early versus delayed passive motion.

PubMed

Li, Shuxiang; Sun, Han; Luo, Xiaomin; Wang, Kun; Wu, Guofeng; Zhou, Jian; Wang, Peng; Sun, Xiaoliang

2018-01-01

The argument on the recommended rehabilitation protocol following arthroscopic rotator cuff repair remains to be resolved. So this meta-analysis was presented to evaluate the differences of clinical effects between the 2 distinct rehabilitation protocols after arthroscopic rotator cuff repair. The PubMed, Cochrane Library, Web of Science, and EMBASE were systematically searched. Only randomized controlled trials (RCTs) published up to July 25, 2017, comparing early passive motion (EPM) versus delayed passive motion (DPM) rehabilitation protocols following arthroscopic rotator cuff repair were identified. The primary outcomes included range of motion and healing rate, while the secondary outcomes were Constant score, American Shoulder and Elbow Society (ASES) score, and Simple Shoulder Test (SST) score. The exclusion criteria contained biochemical trials, reviews, case reports, retrospective studies, without mention about passive motion exercise, no assessment of outcomes mentioned above, and no comparison of EPM and DPM rehabilitation protocols. Eight RCTs with 671 patients were enrolled in this study. The EPM resulted in improved shoulder forward flexion at short term, mid-term, and long-term follow-ups. The EPM group was superior to the DPM group in terms of external rotation (ER) at short-term and mid-term follow-ups. However, the DPM performed better long-term ASES score. These 2 protocols were equivalent in terms of ER at long term, ASES score at mid-term, SST score, Constant score, and healing rate. After excluding 2 RCTs that examined only small- and medium-sized tears, the pooled results of healing rate decreased from 82.4% to 76.6% in the EPM and 86.9% to 85.9% in the DPM. The meta-analysis suggests that the EPM protocol results in superior ROM recovery after arthroscopic rotator cuff repair but may adversely affect the shoulder function, which should be supported by further research. The healing rate at long-term follow-up is not clearly affected by the type of rehabilitation, but the EPM protocol might result in lower rates of tendon healing in the shoulder with large-sized tendon tears. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Comparative Effectiveness of New Mechanical Irrigant Agitating Devices for Debris Removal from the Canal and Isthmus of Mesial Roots of Mandibular Molars.

PubMed

Duque, Jussaro Alves; Duarte, Marco Antonio Hungaro; Canali, Lyz Cristina Furquim; Zancan, Rafaela Fernandes; Vivan, Rodrigo Ricci; Bernardes, Ricardo Affonso; Bramante, Clovis Monteiro

2017-02-01

The aim of this study was to compare the effectiveness of Easy Clean (Easy Dental Equipment, Belo Horizonte, MG, Brazil) in continuous and reciprocating motion, passive ultrasonic irrigation (PUI), Endoactivator systems (Dentsply Maillefer, Ballaigues, Switzerland), and conventional irrigation for debris removal from root canals and isthmus. Fifty mesial roots of mandibular molars were embedded in epoxy resin using a metal muffle; afterward, the blocks containing the roots were sectioned at 2, 4, and 6 mm from the apex. After instrumentation, the roots were divided into 5 groups (n = 10) for application of the final irrigation protocol using Easy Clean in continuous rotation, Easy Clean in reciprocating motion, PUI, Endoactivator, and conventional irrigation. Scanning electron microscopic images were taken after instrumentation and after the first, second, and third activation of irrigating solution to evaluate the area of remaining debris with image J software (National Institutes of Health, Bethesda, MD). The protocol of 3 irrigating solution activations for 20 seconds provided better cleaning of the canal and isthmus. On conclusion of all procedures, analysis of the canals showed a statistical difference only at 2 mm; the Easy Clean in continuous rotation was more efficient than conventional irrigation (P < .05). On conclusion of all steps, the largest difference was observed in the isthmus in which the Easy Clean in continuous rotation was more effective than conventional irrigation at the 3 levels analyzed and the Endoactivator at 4 mm (P < .05). The PUI promoted greater cleaning than conventional irrigation at 6 mm (P < .05). There was no statistical difference between Easy Clean in continuous rotation, Easy Clean in reciprocating motion, and PUI (P > .05). Irrigating solution activation methods provided better cleaning of the canal and isthmus, especially the Easy Clean used in continuous rotation. The protocol of 3 irrigating solution activations for 20 seconds favored better cleaning. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Remarques sur le Passif (suite) (Remarks on the Passive, Continued)

ERIC Educational Resources Information Center

Pinchon, Jacqueline

1977-01-01

The continuation of articles on the passive voice appearing in the "Grammaire vivante" section of the periodical. The production of the passive sentence is considered under two headings: the simple verb and the complex verbal group. (Text is in French.) (AMH)

Effects of high-intensity pulse irradiation with linear polarized near-infrared rays and stretching on muscle tone in patients with cerebrovascular disease: a randomized controlled trial.

PubMed

Takeuchi, Nobuyuki; Takezako, Nobuhiro; Shimonishi, Yuko; Usuda, Shigeru

2017-08-01

[Purpose] The purpose of this study was to clarify the influence of high-intensity pulse irradiation with linear polarized near-infrared rays (HI-LPNR) and stretching on hypertonia in cerebrovascular disease patients. [Subjects and Methods] The subjects were 40 cerebrovascular disease patients with hypertonia of the ankle joint plantar flexor muscle. The subjects were randomly allocated to groups undergoing treatment with HI-LPNR irradiation (HI-LPNR group), stretching (stretching group), HI-LPNR irradiation followed by stretching (combination group), and control group (10 subjects each). In all groups, the passive range of motion of ankle dorsiflexion and passive resistive joint torque of ankle dorsiflexion were measured before and after the specified intervention. [Results] The changes in passive range of motion, significant increase in the stretching and combination groups compared with that in the control group. The changes in passive resistive joint torque, significant decrease in HI-LPNR, stretching, and combination groups compared with that in the control group. [Conclusion] HI-LPNR irradiation and stretching has effect of decrease muscle tone. However, combination of HI-LPNR irradiation and stretching has no multiplier effect.

Hip Rotation Range of Motion in People With and Without Low Back Pain Who Participate in Rotation-Related Sports

PubMed Central

Van Dillen, Linda R.; Bloom, Nancy J.; Gombatto, Sara P.; Susco, Thomas M.

2008-01-01

Objective To examine whether passive hip rotation motion was different between people with and without low back pain (LBP) who regularly participate in sports that require repeated rotation of the trunk and hips. We hypothesized that people with LBP would have less total hip rotation motion and more asymmetry of motion between sides than people without LBP. Design Two group, case-control. Setting University-based musculoskeletal analysis laboratory. Participants Forty-eight subjects (35 males, 13 females; mean age: 26.56±7.44 years) who reported regular participation in a rotation-related sport participated. Two groups were compared; people with LBP (N=24) and people without LBP (N=24; NoLBP). Main outcome measures Data were collected on participant-related, LBP-related, sport-related and activity-related variables. Measures of passive hip rotation range of motion were obtained. The differences between the LBP and NoLBP groups were examined. Results People with and without a history of LBP were the same with regard to all participant-related, sport-related and activity-related variables. The LBP group had significantly less total rotation (P=.035) and more asymmetry of total rotation, right hip versus left hip, (P=.022) than the NoLBP group. Left total hip rotation was more limited than right total hip rotation in the LBP group (P=.004). There were no significant differences in left and right total hip rotation for the NoLBP group (P=.323). Conclusions Among people who participate in rotation-related sports, those with LBP had less overall passive hip rotation motion and more asymmetry of rotation between sides than people without LBP. These findings suggest that the specific directional demands imposed on the hip and trunk during regularly performed activities may be an important consideration in deciding which impairments may be most relevant to test and to consider in prevention and intervention strategies. PMID:19081817

The Neural Correlates of Shoulder Apprehension: A Functional MRI Study

PubMed Central

Shitara, Hitoshi; Shimoyama, Daisuke; Sasaki, Tsuyoshi; Hamano, Noritaka; Ichinose, Tsuyoshi; Yamamoto, Atsushi; Kobayashi, Tsutomu; Osawa, Toshihisa; Iizuka, Haku; Hanakawa, Takashi; Tsushima, Yoshito; Takagishi, Kenji

2015-01-01

Although shoulder apprehension is an established clinical finding and is important for the prevention of shoulder dislocation, how this subjective perception is evoked remains unclear. We elucidated the functional neuroplasticity associated with apprehension in patients with recurrent anterior shoulder instability (RSI) using functional magnetic resonance imaging (fMRI). Twelve healthy volunteers and 14 patients with right-sided RSI performed a motor imagery task and a passive shoulder motion task. Brain activity was compared between healthy participants and those with RSI and was correlated with the apprehension intensity reported by participants after each task. Compared to healthy volunteers, participants with RSI exhibited decreased brain activity in the motor network, but increased activity in the hippocampus and amygdala. During the passive motion task, participants with RSI exhibited decreased activity in the left premotor and primary motor/somatosensory areas. Furthermore, brain activity was correlated with apprehension intensity in the left amygdala and left thalamus during the motor imagery task (memory-induced), while a correlation between apprehension intensity and brain activity was found in the left prefrontal cortex during the passive motion task (instability-induced). Our findings provide insight into the pathophysiology of RSI by identifying its associated neural alterations. We elucidated that shoulder apprehension was induced by two different factors, namely instability and memory. PMID:26351854

Thrust Stand for Electric Propulsion Performance Evaluation

NASA Technical Reports Server (NTRS)

Markusic, T. E.; Jones, J. E.; Cox, M. D.

2004-01-01

An electric propulsion thrust stand capable of supporting thrusters with total mass of up to 125 kg and 1 mN to 1 N thrust levels has been developed and tested. The mechanical design features a conventional hanging pendulum arm attached to a balance mechanism that transforms horizontal motion into amplified vertical motion, with accommodation for variable displacement sensitivity. Unlike conventional hanging pendulum thrust stands, the deflection is independent of the length of the pendulum arm, and no reference structure is required at the end of the pendulum. Displacement is measured using a non-contact, optical linear gap displacement transducer. Mechanical oscillations are attenuated using a passive, eddy current damper. An on-board microprocessor-based level control system, which includes a two axis accelerometer and two linear-displacement stepper motors, continuously maintains the level of the balance mechanism - counteracting mechanical %era drift during thruster testing. A thermal control system, which includes heat exchange panels, thermocouples, and a programmable recirculating water chiller, continuously adjusts to varying thermal loads to maintain the balance mechanism temperature, to counteract thermal drifts. An in-situ calibration rig allows for steady state calibration both prior to and during thruster testing. Thrust measurements were carried out on a well-characterized 1 kW Hall thruster; the thrust stand was shown to produce repeatable results consistent with previously published performance data.

Comparison of an indirect tri-planar myofascial release (MFR) technique and a hot pack for increasing range of motion.

PubMed

Kain, Jay; Martorello, Laura; Swanson, Edward; Sego, Sandra

2011-01-01

The purpose of the randomized clinical study was to scientifically assess which intervention increases passive range of motion most effectively: the indirect tri-planar myofascial release (MFR) technique or the application of hot packs for gleno-humeral joint flexion, extension, and abduction. A total of 31 participants from a sample of convenience were randomly assigned to examine whether or not MFR was as effective in increasing range of motion as hot packs. The sample consisted of students at American International College. Students were randomly assigned to two groups: hot pack application (N=13) or MFR technique (N=18). The independent variable was the intervention, either the tri-planar MFR technique or the hot pack application. Group one received the indirect tri-planar MFR technique once for 3min. Group two received one hot pack application for 20min. The dependent variables, passive gleno-humeral shoulder range of motion in shoulder flexion, shoulder extension, and shoulder abduction, were taken pre- and post-intervention for both groups. Data was analyzed through the use of a two-way factorial design with mixed-factors ANOVA. Prior to conducting the study, inter-rater reliability was established using three testers for goniometric measures. A 2 (type of intervention: hot packs or MFR) by 2 (pre-test or post-test) mixed-factors ANOVA was calculated. Significant increases in range of motion were found for flexion, extension and abduction when comparing pre-test scores to post-test scores. The results of the ANOVA showed that for passive range of motion no differences were found for flexion, extension and abduction between the effectiveness of hot packs and MFR. For each of the dependent variables measured, MFR was shown to be as effective as hot packs in increasing range of motion, supporting the hypothesis. Since there was no significant difference between the types of intervention, both the hot pack application and the MFR technique were found to be equally effective in increasing passive range of motion of the joint in flexion, extension, and abduction of the gleno-humeral joint. The indirect tri-planar intervention could be considered more effective as an intervention in terms of time spent with a patient and the number of patients seen in a 20-min period. No equipment is required to carry out the MFR intervention, whereby using a hot pack requires the hot pack, towels, and a hydraculator unit with the use of the indirect tri-planar intervention, a therapist could treat four to five patients in the time it would take for one standard hot pack treatment of 20min, less the hands-on intervention of the therapist. Copyright © 2009 Elsevier Ltd. All rights reserved.

Calcific tendinopathy of the rotator cuff. Conservative management with 434 Mhz local microwave diathermy (hyperthermia): a case study.

PubMed

Di Cesare, Annalisa; Giombini, Arrigo; Dragoni, Stefano; Agnello, Luciano; Ripani, Maurizio; Saraceni, Vincenzo Maria; Maffulli, Nicola

2008-01-01

To report the effects of local microwave diathermy (hyperthermia) at 434 Mhz on calcific tendinopathy of the shoulder in two middle aged patients. Two middle-aged women with calcific tendinopathy of the shoulder were treated with local microwave diathermy (hyperthermia) at 434 Mhz three times a week for four weeks. Plain radiographs and ultrasonography demonstrated calcific deposits in the area of infraspinatus or supraspinatus. Shoulder Pain and Disability Index (SPADI) and passive Range of Motion (ROM) were used to assess the response to treatment. At the end of the treatment period, the improvement as measured by the SPADI score was respectively 30% for the first patient and 40% for the second patient with an improvement of the shoulder passive ROM for both patients. The calcific deposits seen on the initial radiographs and ultrasonography were no longer visible. At 1 year follow-up, both patients continued to be symptom free. Hyperthermia is a safe option in the management of calcific tendinopathy of the shoulder. Prospective randomized controlled studies with long term assessment are needed to further document its therapeutic efficacy.

The VSPA Foot: A Quasi-Passive Ankle-Foot Prosthesis With Continuously Variable Stiffness.

PubMed

Shepherd, Max K; Rouse, Elliott J

2017-12-01

Most commercially available prosthetic feet do not exhibit a biomimetic torque-angle relationship, and are unable to modulate their mechanics to assist with other mobility tasks, such as stairs and ramps. In this paper, we present a quasi-passive ankle-foot prosthesis with a customizable torque-angle curve and an ability to quickly modulate ankle stiffness between tasks. The customizable torque-angle curve is obtained with a cam-based transmission and a fiberglass leaf spring. To achieve variable stiffness, the leaf spring's support conditions can be actively modulated by a small motor, shifting the torque-angle curve to be more or less stiff. We introduce the design, characterize the available torque-angle curves, and present kinematics from a transtibial amputee subject performing level-ground walking, stair ascent/descent, and ramp ascent/descent. The subject exhibited a more normative range of motion on stairs and ramps at lower stiffness levels, and preferred different stiffness levels for each task. Paired with an appropriate intent recognition system, our novel ankle prosthesis could improve gait biomechanics during walking and many other mobility tasks.

An experimental and three-dimensional computational study on the aerodynamic contribution to the passive pitching motion of flapping wings in hovering flies.

PubMed

Ishihara, D; Horie, T; Niho, T

2014-11-07

The relative importance of the wing's inertial and aerodynamic forces is the key to revealing how the kinematical characteristics of the passive pitching motion of insect flapping wings are generated, which is still unclear irrespective of its importance in the design of insect-like micro air vehicles. Therefore, we investigate three species of flies in order to reveal this, using a novel fluid-structure interaction analysis that consists of a dynamically scaled experiment and a three-dimensional finite element analysis. In the experiment, the dynamic similarity between the lumped torsional flexibility model as a first approximation of the dipteran wing and the actual insect is measured by the Reynolds number Re, the Strouhal number St, the mass ratio M, and the Cauchy number Ch. In the computation, the three-dimension is important in order to simulate the stable leading edge vortex and lift force in the present Re regime over 254. The drawback of the present experiment is the difficulty in satisfying the condition of M due to the limitation of available solid materials. The novelty of the present analysis is to complement this drawback using the computation. We analyze the following two cases: (a) The equilibrium between the wing's elastic and fluid forces is dynamically similar to that of the actual insect, while the wing's inertial force can be ignored. (b) All forces are dynamically similar to those of the actual insect. From the comparison between the results of cases (a) and (b), we evaluate the contributions of the equilibrium between the aerodynamic and the wing's elastic forces and the wing's inertial force to the passive pitching motion as 80-90% and 10-20%, respectively. It follows from these results that the dipteran passive pitching motion will be based on the equilibrium between the wing's elastic and aerodynamic forces, while it will be enhanced by the wing's inertial force.

Prediction of primary somatosensory neuron activity during active tactile exploration

PubMed Central

Campagner, Dario; Evans, Mathew Hywel; Bale, Michael Ross; Erskine, Andrew; Petersen, Rasmus Strange

2016-01-01

Primary sensory neurons form the interface between world and brain. Their function is well-understood during passive stimulation but, under natural behaving conditions, sense organs are under active, motor control. In an attempt to predict primary neuron firing under natural conditions of sensorimotor integration, we recorded from primary mechanosensory neurons of awake, head-fixed mice as they explored a pole with their whiskers, and simultaneously measured both whisker motion and forces with high-speed videography. Using Generalised Linear Models, we found that primary neuron responses were poorly predicted by whisker angle, but well-predicted by rotational forces acting on the whisker: both during touch and free-air whisker motion. These results are in apparent contrast to previous studies of passive stimulation, but could be reconciled by differences in the kinematics-force relationship between active and passive conditions. Thus, simple statistical models can predict rich neural activity elicited by natural, exploratory behaviour involving active movement of sense organs. DOI: http://dx.doi.org/10.7554/eLife.10696.001 PMID:26880559

Improvements in hip flexibility do not transfer to mobility in functional movement patterns.

PubMed

Moreside, Janice M; McGill, Stuart M

2013-10-01

The purpose of this study was to analyze the transference of increased passive hip range of motion (ROM) and core endurance to functional movement. Twenty-four healthy young men with limited hip mobility were randomly assigned to 4 intervention groups: group 1, stretching; group 2, stretching plus hip/spine disassociation exercises; group 3, core endurance; and group 4, control. Previous work has documented the large increase in passive ROM and core endurance that was attained over the 6-week interventions, but whether these changes transferred to functional activities was unclear. Four dynamic activities were analyzed before and after the 6-week interventions: active standing hip extension, lunge, a standing twist/reach maneuver, and exercising on an elliptical trainer. A Vicon motion capture system collected body segment kinematics, with hip and lumbar spine angles subsequently calculated in Visual 3D. Repeated measures analyses of variance determined group effects on various hip and spine angles, with paired t-tests on specific pre/post pairs. Despite the large increases in passive hip ROM, there was no evidence of increased hip ROM used during functional movement testing. Similarly, the only significant change in lumbar motion was a reduction in lumbar rotation during the active hip extension maneuver (p < 0.05). These results indicate that changes in passive ROM or core endurance do not automatically transfer to changes in functional movement patterns. This implies that training and rehabilitation programs may benefit from an additional focus on 'grooving' new motor patterns if newfound movement range is to be used.

Deciding what to see: the role of intention and attention in the perception of apparent motion.

PubMed

Kohler, Axel; Haddad, Leila; Singer, Wolf; Muckli, Lars

2008-03-01

Apparent motion is an illusory perception of movement that can be induced by alternating presentations of static objects. Already in Wertheimer's early investigation of the phenomenon [Wertheimer, M. (1912). Experimentelle Studien über das Sehen von Bewegung. Zeitschrift fur Psychologie, 61, 161-265], he mentions that voluntary attention can influence the way in which an ambiguous apparent motion display is perceived. But until now, few studies have investigated how strong the modulation of apparent motion through attention can be under different stimulus and task conditions. We used bistable motion quartets of two different sizes, where the perception of vertical and horizontal motion is equally likely. Eleven observers participated in two experiments. In Experiment 1, participants were instructed to either (a) hold the current movement direction as long as possible, (b) passively view the stimulus, or (c) switch the movement directions as quickly as possible. With the respective instructions, observers could almost double phase durations in (a) and more than halve durations in (c) relative to the passive condition. This modulation effect was stronger for the large quartets. In Experiment 2, observers' attention was diverted from the stimulus by a detection task at fixation while they still had to report their conscious perception. This manipulation prolonged dominance durations for up to 100%. The experiments reveal a high susceptibility of ambiguous apparent motion to attentional modulation. We discuss how feature- and space-based attention mechanisms might contribute to those effects.

Stretching of Active Muscle Elicits Chronic Changes in Multiple Strain Risk Factors.

PubMed

Kay, Anthony David; Richmond, Dominic; Talbot, Chris; Mina, Minas; Baross, Anthony William; Blazevich, Anthony John

2016-07-01

The muscle stretch intensity imposed during "flexibility" training influences the magnitude of joint range of motion (ROM) adaptation. Thus, stretching while the muscle is voluntarily activated was hypothesized to provide a greater stimulus than passive stretching. The effect of a 6-wk program of stretch imposed on an isometrically contracting muscle (i.e., qualitatively similar to isokinetic eccentric training) on muscle-tendon mechanics was therefore studied in 13 healthy human volunteers. Before and after the training program, dorsiflexion ROM, passive joint moment, and maximal isometric plantarflexor moment were recorded on an isokinetic dynamometer. Simultaneous real-time motion analysis and ultrasound imaging recorded gastrocnemius medialis muscle and Achilles tendon elongation. Training was performed twice weekly and consisted of five sets of 12 maximal isokinetic eccentric contractions at 10°·s. Significant increases (P < 0.01) in ROM (92.7% [14.7°]), peak passive moment (i.e., stretch tolerance; 136.2%), area under the passive moment curve (i.e., energy storage; 302.6%), and maximal isometric plantarflexor moment (51.3%) were observed after training. Although no change in the slope of the passive moment curve (muscle-tendon stiffness) was detected (-1.5%, P > 0.05), a significant increase in tendon stiffness (31.2%, P < 0.01) and a decrease in passive muscle stiffness (-14.6%, P < 0.05) were observed. The substantial positive adaptation in multiple functional and physiological variables that are cited within the primary etiology of muscle strain injury, including strength, ROM, muscle stiffness, and maximal energy storage, indicate that the stretching of active muscle might influence injury risk in addition to muscle function. The lack of change in muscle-tendon stiffness simultaneous with significant increases in tendon stiffness and decreases in passive muscle stiffness indicates that tissue-specific effects were elicited.

Smart portable rehabilitation devices.

PubMed

Mavroidis, Constantinos; Nikitczuk, Jason; Weinberg, Brian; Danaher, Gil; Jensen, Katherine; Pelletier, Philip; Prugnarola, Jennifer; Stuart, Ryan; Arango, Roberto; Leahey, Matt; Pavone, Robert; Provo, Andrew; Yasevac, Dan

2005-07-12

The majority of current portable orthotic devices and rehabilitative braces provide stability, apply precise pressure, or help maintain alignment of the joints with out the capability for real time monitoring of the patient's motions and forces and without the ability for real time adjustments of the applied forces and motions. Improved technology has allowed for advancements where these devices can be designed to apply a form of tension to resist motion of the joint. These devices induce quicker recovery and are more effective at restoring proper biomechanics and improving muscle function. However, their shortcoming is in their inability to be adjusted in real-time, which is the most ideal form of a device for rehabilitation. This introduces a second class of devices beyond passive orthotics. It is comprised of "active" or powered devices, and although more complicated in design, they are definitely the most versatile. An active or powered orthotic, usually employs some type of actuator(s). In this paper we present several new advancements in the area of smart rehabilitation devices that have been developed by the Northeastern University Robotics and Mechatronics Laboratory. They are all compact, wearable and portable devices and boast re-programmable, real time computer controlled functions as the central theme behind their operation. The sensory information and computer control of the three described devices make for highly efficient and versatile systems that represent a whole new breed in wearable rehabilitation devices. Their applications range from active-assistive rehabilitation to resistance exercise and even have applications in gait training. The three devices described are: a transportable continuous passive motion elbow device, a wearable electro-rheological fluid based knee resistance device, and a wearable electrical stimulation and biofeedback knee device. Laboratory tests of the devices demonstrated that they were able to meet their design objectives. The prototypes of portable rehabilitation devices presented here did demonstrate that these concepts are capable of the performance their commercially available but non-portable counterparts exhibit. Smart, portable devices with the ability for real time monitoring and adjustment open a new era in rehabilitation where the recovery process could be dramatically improved.

Smart portable rehabilitation devices

PubMed Central

Mavroidis, Constantinos; Nikitczuk, Jason; Weinberg, Brian; Danaher, Gil; Jensen, Katherine; Pelletier, Philip; Prugnarola, Jennifer; Stuart, Ryan; Arango, Roberto; Leahey, Matt; Pavone, Robert; Provo, Andrew; Yasevac, Dan

2005-01-01

Background The majority of current portable orthotic devices and rehabilitative braces provide stability, apply precise pressure, or help maintain alignment of the joints with out the capability for real time monitoring of the patient's motions and forces and without the ability for real time adjustments of the applied forces and motions. Improved technology has allowed for advancements where these devices can be designed to apply a form of tension to resist motion of the joint. These devices induce quicker recovery and are more effective at restoring proper biomechanics and improving muscle function. However, their shortcoming is in their inability to be adjusted in real-time, which is the most ideal form of a device for rehabilitation. This introduces a second class of devices beyond passive orthotics. It is comprised of "active" or powered devices, and although more complicated in design, they are definitely the most versatile. An active or powered orthotic, usually employs some type of actuator(s). Methods In this paper we present several new advancements in the area of smart rehabilitation devices that have been developed by the Northeastern University Robotics and Mechatronics Laboratory. They are all compact, wearable and portable devices and boast re-programmable, real time computer controlled functions as the central theme behind their operation. The sensory information and computer control of the three described devices make for highly efficient and versatile systems that represent a whole new breed in wearable rehabilitation devices. Their applications range from active-assistive rehabilitation to resistance exercise and even have applications in gait training. The three devices described are: a transportable continuous passive motion elbow device, a wearable electro-rheological fluid based knee resistance device, and a wearable electrical stimulation and biofeedback knee device. Results Laboratory tests of the devices demonstrated that they were able to meet their design objectives. The prototypes of portable rehabilitation devices presented here did demonstrate that these concepts are capable of the performance their commercially available but non-portable counterparts exhibit. Conclusion Smart, portable devices with the ability for real time monitoring and adjustment open a new era in rehabilitation where the recovery process could be dramatically improved. PMID:16011801

Moving along the Mental Number Line: Interactions between Whole-Body Motion and Numerical Cognition

ERIC Educational Resources Information Center

Hartmann, Matthias; Grabherr, Luzia; Mast, Fred W.

2012-01-01

Active head turns to the left and right have recently been shown to influence numerical cognition by shifting attention along the mental number line. In the present study, we found that passive whole-body motion influences numerical cognition. In a random-number generation task (Experiment 1), leftward and downward displacement of participants…

Reliability and concurrent validity of a Smartphone, bubble inclinometer and motion analysis system for measurement of hip joint range of motion.

PubMed

Charlton, Paula C; Mentiplay, Benjamin F; Pua, Yong-Hao; Clark, Ross A

2015-05-01

Traditional methods of assessing joint range of motion (ROM) involve specialized tools that may not be widely available to clinicians. This study assesses the reliability and validity of a custom Smartphone application for assessing hip joint range of motion. Intra-tester reliability with concurrent validity. Passive hip joint range of motion was recorded for seven different movements in 20 males on two separate occasions. Data from a Smartphone, bubble inclinometer and a three dimensional motion analysis (3DMA) system were collected simultaneously. Intraclass correlation coefficients (ICCs), coefficients of variation (CV) and standard error of measurement (SEM) were used to assess reliability. To assess validity of the Smartphone application and the bubble inclinometer against the three dimensional motion analysis system, intraclass correlation coefficients and fixed and proportional biases were used. The Smartphone demonstrated good to excellent reliability (ICCs>0.75) for four out of the seven movements, and moderate to good reliability for the remaining three movements (ICC=0.63-0.68). Additionally, the Smartphone application displayed comparable reliability to the bubble inclinometer. The Smartphone application displayed excellent validity when compared to the three dimensional motion analysis system for all movements (ICCs>0.88) except one, which displayed moderate to good validity (ICC=0.71). Smartphones are portable and widely available tools that are mostly reliable and valid for assessing passive hip range of motion, with potential for large-scale use when a bubble inclinometer is not available. However, caution must be taken in its implementation as some movement axes demonstrated only moderate reliability. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Passive magnetic bearing systems stabilizer/bearing utilizing time-averaging of a periodic magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Post, Richard F.

A high-stiffness stabilizer/bearings for passive magnetic bearing systems is provide where the key to its operation resides in the fact that when the frequency of variation of the repelling forces of the periodic magnet array is large compared to the reciprocal of the growth time of the unstable motion, the rotating system will feel only the time-averaged value of the force. When the time-averaged value of the force is radially repelling by the choice of the geometry of the periodic magnet array, the Earnshaw-related unstable hit motion that would occur at zero rotational speed is suppressed when the system ismore » rotating at operating speeds.« less

The role of large scale motions on passive scalar transport

NASA Astrophysics Data System (ADS)

Dharmarathne, Suranga; Araya, Guillermo; Tutkun, Murat; Leonardi, Stefano; Castillo, Luciano

2014-11-01

We study direct numerical simulation (DNS) of turbulent channel flow at Reτ = 394 to investigate effect of large scale motions on fluctuating temperature field which forms a passive scalar field. Statistical description of the large scale features of the turbulent channel flow is obtained using two-point correlations of velocity components. Two-point correlations of fluctuating temperature field is also examined in order to identify possible similarities between velocity and temperature fields. The two-point cross-correlations betwen the velocity and temperature fluctuations are further analyzed to establish connections between these two fields. In addition, we use proper orhtogonal decompotion (POD) to extract most dominant modes of the fields and discuss the coupling of large scale features of turbulence and the temperature field.

A large motion zero-gravity suspension system for experimental simulation of orbital construction and deployment. M.S. Thesis

NASA Technical Reports Server (NTRS)

Straube, Timothy Milton

1993-01-01

The design and implementation of a vertical degree of freedom suspension system is described which provides a constant force off-load condition to counter gravity over large displacements. By accommodating motions up to one meter for structures weighing up to 100 pounds, the system is useful for experiments which simulate orbital construction events such as docking, multiple component assembly, or structural deployment. A unique aspect of this device is the combination of a large stroke passive off-load device augmented by electromotive torque actuated force feedback. The active force feedback has the effect of reducing break-away friction by a factor of twenty over the passive system alone. The thesis describes the development of the suspension hardware and the control algorithm. Experiments were performed to verify the suspensions system's effectiveness in providing a gravity off-load and simulating the motion of a structure in orbit. Additionally, a three dimensional system concept is presented as an extension of the one dimensional suspension system which was implemented.

Motion-based threat detection using microrods: experiments and numerical simulations.

PubMed

Ezhilan, Barath; Gao, Wei; Pei, Allen; Rozen, Isaac; Dong, Renfeng; Jurado-Sanchez, Beatriz; Wang, Joseph; Saintillan, David

2015-05-07

Motion-based chemical sensing using microscale particles has attracted considerable recent attention. In this paper, we report on new experiments and Brownian dynamics simulations that cast light on the dynamics of both passive and active microrods (gold wires and gold-platinum micromotors) in a silver ion gradient. We demonstrate that such microrods can be used for threat detection in the form of a silver ion source, allowing for the determination of both the location of the source and concentration of silver. This threat detection strategy relies on the diffusiophoretic motion of both passive and active microrods in the ionic gradient and on the speed acceleration of the Au-Pt micromotors in the presence of silver ions. A Langevin model describing the microrod dynamics and accounting for all of these effects is presented, and key model parameters are extracted from the experimental data, thereby providing a reliable estimate for the full spatiotemporal distribution of the silver ions in the vicinity of the source.

Image Processing Occupancy Sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

The Image Processing Occupancy Sensor, or IPOS, is a novel sensor technology developed at the National Renewable Energy Laboratory (NREL). The sensor is based on low-cost embedded microprocessors widely used by the smartphone industry and leverages mature open-source computer vision software libraries. Compared to traditional passive infrared and ultrasonic-based motion sensors currently used for occupancy detection, IPOS has shown the potential for improved accuracy and a richer set of feedback signals for occupant-optimized lighting, daylighting, temperature setback, ventilation control, and other occupancy and location-based uses. Unlike traditional passive infrared (PIR) or ultrasonic occupancy sensors, which infer occupancy based only onmore » motion, IPOS uses digital image-based analysis to detect and classify various aspects of occupancy, including the presence of occupants regardless of motion, their number, location, and activity levels of occupants, as well as the illuminance properties of the monitored space. The IPOS software leverages the recent availability of low-cost embedded computing platforms, computer vision software libraries, and camera elements.« less

Modification of Motion Perception and Manual Control Following Short-Durations Spaceflight

NASA Technical Reports Server (NTRS)

Wood, S. J.; Vanya, R. D.; Esteves, J. T.; Rupert, A. H.; Clement, G.

2011-01-01

Adaptive changes during space flight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination and spatial disorientation following G-transitions. This ESA-NASA study was designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances following short-duration spaceflights. The goals of this study were to (1) examine the effects of stimulus frequency on adaptive changes in motion perception during passive tilt and translation motion, (2) quantify decrements in manual control of tilt motion, and (3) evaluate vibrotactile feedback as a sensorimotor countermeasure.

Sea ice motion from low-resolution satellite sensors: An alternative method and its validation in the Arctic

NASA Astrophysics Data System (ADS)

Lavergne, T.; Eastwood, S.; Teffah, Z.; Schyberg, H.; Breivik, L.-A.

2010-10-01

The retrieval of sea ice motion with the Maximum Cross-Correlation (MCC) method from low-resolution (10-15 km) spaceborne imaging sensors is challenged by a dominating quantization noise as the time span of displacement vectors is shortened. To allow investigating shorter displacements from these instruments, we introduce an alternative sea ice motion tracking algorithm that builds on the MCC method but relies on a continuous optimization step for computing the motion vector. The prime effect of this method is to effectively dampen the quantization noise, an artifact of the MCC. It allows for retrieving spatially smooth 48 h sea ice motion vector fields in the Arctic. Strategies to detect and correct erroneous vectors as well as to optimally merge several polarization channels of a given instrument are also described. A test processing chain is implemented and run with several active and passive microwave imagers (Advanced Microwave Scanning Radiometer-EOS (AMSR-E), Special Sensor Microwave Imager, and Advanced Scatterometer) during three Arctic autumn, winter, and spring seasons. Ice motion vectors are collocated to and compared with GPS positions of in situ drifters. Error statistics are shown to be ranging from 2.5 to 4.5 km (standard deviation for components of the vectors) depending on the sensor, without significant bias. We discuss the relative contribution of measurement and representativeness errors by analyzing monthly validation statistics. The 37 GHz channels of the AMSR-E instrument allow for the best validation statistics. The operational low-resolution sea ice drift product of the EUMETSAT OSI SAF (European Organisation for the Exploitation of Meteorological Satellites Ocean and Sea Ice Satellite Application Facility) is based on the algorithms presented in this paper.

Multiradar tracking for theater missile defense

NASA Astrophysics Data System (ADS)

Sviestins, Egils

1995-09-01

A prototype system for tracking tactical ballistic missiles using multiple radars has been developed. The tracking is based on measurement level fusion (`true' multi-radar) tracking. Strobes from passive sensors can also be used. We describe various features of the system with some emphasis on the filtering technique. This is based on the Interacting Multiple Model framework where the states are Free Flight, Drag, Boost, and Auxiliary. Measurement error modeling includes the signal to noise ratio dependence; outliers and miscorrelations are handled in the same way. The launch point is calculated within one minute from the detection of the missile. The impact point, and its uncertainty region, is calculated continually by extrapolating the track state vector using the equations of planetary motion.

Clearing out a maze: A model of chemotactic motion in porous media

NASA Astrophysics Data System (ADS)

Schilling, Tanja; Voigtmann, Thomas

2017-12-01

We study the anomalous dynamics of a biased "hungry" (or "greedy") random walk on a percolating cluster. The model mimics chemotaxis in a porous medium: In close resemblance to the 1980s arcade game PAC-MA N ®, the hungry random walker consumes food, which is initially distributed in the maze, and biases its movement towards food-filled sites. We observe that the mean-squared displacement of the process follows a power law with an exponent that is different from previously known exponents describing passive or active microswimmer dynamics. The change in dynamics is well described by a dynamical exponent that depends continuously on the propensity to move towards food. It results in slower differential growth when compared to the unbiased random walk.

26 CFR 1.469-3 - Passive activity credit.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 6 2010-04-01 2010-04-01 false Passive activity credit. 1.469-3 Section 1.469-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Taxable Year for Which Deductions Taken § 1.469-3 Passive activity credit. (a)-(d) [Reserved...

StopWatch: The preliminary evaluation of a smartwatch-based system for passive detection of cigarette smoking.

PubMed

Skinner, Andrew L; Stone, Christopher J; Doughty, Hazel; Munafò, Marcus R

2018-01-24

Recent developments in smoking cessation support systems and interventions have highlighted the requirement for unobtrusive, passive ways to measure smoking behaviour. A number of systems have been developed for this that either use bespoke sensing technology, or expensive combinations of wearables and smartphones. Here we present StopWatch, a system for passive detection of cigarette smoking that runs on a low-cost smartwatch and does not require additional sensing or a connected smartphone. Our system uses motion data from the accelerometer and gyroscope in an Android smartwatch to detect the signature hand movements of cigarette smoking. It uses machine learning techniques to transform raw motion data into motion features, and in turn into individual drags and instances of smoking. These processes run on the smartwatch, and do not require a smartphone. We conducted preliminary validations of the system in daily smokers (n=13) in laboratory and free-living conditions running on an Android LG G-Watch. In free-living conditions, over a 24-hour period, the system achieved precision of 86% and recall of 71%. StopWatch is a system for passive measurement of cigarette smoking that runs entirely on a commercially available Android smartwatch. It requires no smartphone so the cost is low, and needs no bespoke sensing equipment so participant burden is also low. Performance is currently lower than other more expensive and complex systems, though adequate for some applications. Future developments will focus on enhancing performance, validation on a range of smartwatches, and detection of electronic cigarette use. We present a low-cost, smartwatch-based system for passive detection of cigarette smoking. It uses data from the motion sensors in the watch to identify the signature hand movements of cigarette smoking. The system will provide the detailed measures of individual smoking behaviour needed for context-triggered just-in-time smoking cessation support systems, and to enable just-in-time adaptive interventions. More broadly, the system will enable researchers to obtain detailed measures of individual smoking behaviour in free-living conditions that are free from the recall errors and reporting biases associated with self-report of smoking. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco.

Computational knee ligament modeling using experimentally determined zero-load lengths.

PubMed

Bloemker, Katherine H; Guess, Trent M; Maletsky, Lorin; Dodd, Kevin

2012-01-01

This study presents a subject-specific method of determining the zero-load lengths of the cruciate and collateral ligaments in computational knee modeling. Three cadaver knees were tested in a dynamic knee simulator. The cadaver knees also underwent manual envelope of motion testing to find their passive range of motion in order to determine the zero-load lengths for each ligament bundle. Computational multibody knee models were created for each knee and model kinematics were compared to experimental kinematics for a simulated walk cycle. One-dimensional non-linear spring damper elements were used to represent cruciate and collateral ligament bundles in the knee models. This study found that knee kinematics were highly sensitive to altering of the zero-load length. The results also suggest optimal methods for defining each of the ligament bundle zero-load lengths, regardless of the subject. These results verify the importance of the zero-load length when modeling the knee joint and verify that manual envelope of motion measurements can be used to determine the passive range of motion of the knee joint. It is also believed that the method described here for determining zero-load length can be used for in vitro or in vivo subject-specific computational models.

Arctic sea-ice variations from time-lapse passive microwave imagery

USGS Publications Warehouse

Campbell, W.J.; Ramseier, R.O.; Zwally, H.J.; Gloersen, P.

1980-01-01

This paper presents: (1) a short historical review of the passive microwave research on sea ice which established the observational and theoretical base permitting the interpretation of the first passive microwave images of Earth obtained by the Nimbus-5 ESMR; (2) the construction of a time-lapse motion picture film of a 16-month set of serial ESMR images to aid in the formidable data analysis task; and (3) a few of the most significant findings resulting from an early analysis of these data, using selected ESMR images to illustrate these findings. ?? 1980 D. Reidel Publishing Co.

Effects of hamstring stretching on passive muscle stiffness vary between hip flexion and knee extension maneuvers.

PubMed

Miyamoto, N; Hirata, K; Kanehisa, H

2017-01-01

The purpose of this study was to examine whether the effects of hamstring stretching on the passive stiffness of each of the long head of the biceps femoris (BFl), semitendinosus (ST), and semimembranosus (SM) vary between passive knee extension and hip flexion stretching maneuvers. In 12 male subjects, before and after five sets of 90 s static stretching, passive lengthening measurements where knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, shear modulus of each muscle was measured by ultrasound shear wave elastography. Both stretching maneuvers significantly increased maximal ROM and decreased passive torque at a given joint angle. Passive knee extension stretching maneuver significantly reduced shear modulus at a given knee joint angle in all of BFl, ST, and SM. In contrast, the stretching effect by passive hip flexion maneuver was significant only in ST and SM. The present findings indicate that the effects of hamstring stretching on individual passive muscles' stiffness vary between passive knee extension and hip flexion stretching maneuvers. In terms of reducing the muscle stiffness of BFl, stretching of the hamstring should be performed by passive knee extension rather than hip flexion. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Bumblebees minimize control challenges by combining active and passive modes in unsteady winds

NASA Astrophysics Data System (ADS)

Ravi, Sridhar; Kolomenskiy, Dmitry; Engels, Thomas; Schneider, Kai; Wang, Chun; Sesterhenn, Jörn; Liu, Hao

2016-10-01

The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight-control and stability challenges. It is critical to understand the strategies insects employ to safely navigate in natural environments. We combined experiments on free flying bumblebees with high-fidelity numerical simulations and lower-order modeling to identify the mechanics that mediate insect flight in unsteady winds. We trained bumblebees to fly upwind towards an artificial flower in a wind tunnel under steady wind and in a von Kármán street formed in the wake of a cylinder. Analysis revealed that at lower frequencies in both steady and unsteady winds the bees mediated lateral movement with body roll - typical casting motion. Numerical simulations of a bumblebee in similar conditions permitted the separation of the passive and active components of the flight trajectories. Consequently, we derived simple mathematical models that describe these two motion components. Comparison between the free-flying live and modeled bees revealed a novel mechanism that enables bees to passively ride out high-frequency perturbations while performing active maneuvers at lower frequencies. The capacity of maintaining stability by combining passive and active modes at different timescales provides a viable means for animals and machines to tackle the challenges posed by complex airflows.

Digital ranges of motion: normal values in young adults.

PubMed

Mallon, W J; Brown, H R; Nunley, J A

1991-09-01

Analysis of the range of motion of fingers was done in young (eighteen to thirty-five year old) adult volunteers with no history of previous injury to their hands. The data show that there are slight differences between the individual digits. Notably, metacarpophalangeal flexion and total active motion increase linearly in proceeding from the index to the small finger. There were also minor differences in comparing sexes. Women have greater extension at the metacarpophalangeal joint in both active and passive motion and have a greater total active motion at all digits as a result. A significant tenodesis effect was found at the distal interphalangeal joint in normal subjects. No differences were found that could be attributable to handedness.

Distinguishing advective and powered motion in self-propelled colloids

NASA Astrophysics Data System (ADS)

Byun, Young-Moo; Lammert, Paul E.; Hong, Yiying; Sen, Ayusman; Crespi, Vincent H.

2017-11-01

Self-powered motion in catalytic colloidal particles provides a compelling example of active matter, i.e. systems that engage in single-particle and collective behavior far from equilibrium. The long-time, long-distance behavior of such systems is of particular interest, since it connects their individual micro-scale behavior to macro-scale phenomena. In such analyses, it is important to distinguish motion due to subtle advective effects—which also has long time scales and length scales—from long-timescale phenomena that derive from intrinsically powered motion. Here, we develop a methodology to analyze the statistical properties of the translational and rotational motions of powered colloids to distinguish, for example, active chemotaxis from passive advection by bulk flow.

Aspects of Turbulent / Non-Turbulent Interfaces

NASA Technical Reports Server (NTRS)

Bisset, D. K.; Hunt, J. C. R.; Rogers, M. M.; Koen, Dennis (Technical Monitor)

1999-01-01

A distinct boundary between turbulent and non-turbulent regions in a fluid of otherwise constant properties is found in many laboratory and engineering turbulent flows, including jets, mixing layers, boundary layers and wakes. Generally, the flow has mean shear in at least one direction within t he turbulent zone, but the non-turbulent zones have no shear (adjacent laminar shear is a different case, e.g. transition in a boundary layer). There may be purely passive differences between the turbulent and non-turbulent zones, e.g. small variations in temperature or scalar concentration, for which turbulent mixing is an important issue. The boundary has several major characteristics of interest for the present study. Firstly, the boundary advances into the non-turbulent fluid, or in other words, nonturbulent fluid is entrained. Secondly, the change in turbulence properties across the boundary is remarkably abrupt; strong turbulent motions come close to the nonturbulent fluid, promoting entrainment. Thirdly, the boundary is irregular with a continually changing convoluted shape, which produces statistical intermittency. Its shape is contorted at all scales of the turbulent motion.

Light Propagation in Turbulent Media

NASA Astrophysics Data System (ADS)

Perez, Dario G.

2003-07-01

First, we make a revision of the up-to-date Passive Scalar Fields properties: also, the refractive index is among them. Afterwards, we formulated the properties that make the family of `isotropic' fractional Brownian motion (with parameter H) a good candidate to simulate the turbulent refractive index. Moreover, we obtained its fractal dimension which matches the estimated by Constantin for passive scalar, and thus the parameter H determines the state of the turbulence. Next, using a path integral velocity representation, with the Markovian model, to calculate the effects of the turbulence over a system of grids. Finally, with the tools of Stochastic Calculus for fractional Brownian motions we studied the ray-equation coming from the Geometric Optics in the turbulent case. Our analysis covers those cases where average temperature gradients are relevant.

The effect of uncontrolled moment and short-term, repeated passive stretching on maximum ankle joint dorsiflexion angle.

PubMed

Gatt, Alfred; Chockalingam, Nachiappan

2012-06-01

Trials investigating ankle joint measurement normally apply a known moment. Maximum ankle angle is affected by foot posture and stretching characteristics of the calf muscles. To investigate whether consistent maximum ankle angles could be achieved without applying a constant moment to all subjects, and whether short, repetitive stretching of the calf muscle tendon unit would produce a difference in the maximum ankle angle. Passive dorsiflexion in 14 healthy participants was captured using an optoelectronic motion analysis system, with the foot placed in 3 postures. The maximum ankle angles for both the neutral and supinated positions did not differ significantly. In general, the majority of subjects (92.8%) showed no increase in the maximum ankle dorsiflexion angle following repetitive brief passive stretching. Only one subject exhibited a significant increase in maximum ankle angle at the neutral position. Since the range of motion of the ankle joint is clearly determined by other physical factors, the maximum ankle dorsiflexion angle can be assessed at both neutral and supinated positions without moment being controlled. Copyright © 2011 Elsevier Ltd. All rights reserved.

Self-motion perception and vestibulo-ocular reflex during whole body yaw rotation in standing subjects: the role of head position and neck proprioception.

PubMed

Panichi, Roberto; Botti, Fabio Massimo; Ferraresi, Aldo; Faralli, Mario; Kyriakareli, Artemis; Schieppati, Marco; Pettorossi, Vito Enrico

2011-04-01

Self-motion perception and vestibulo-ocular reflex (VOR) were studied during whole body yaw rotation in the dark at different static head positions. Rotations consisted of four cycles of symmetric sinusoidal and asymmetric oscillations. Self-motion perception was evaluated by measuring the ability of subjects to manually track a static remembered target. VOR was recorded separately and the slow phase eye position (SPEP) was computed. Three different head static yaw deviations (active and passive) relative to the trunk (0°, 45° to right and 45° to left) were examined. Active head deviations had a significant effect during asymmetric oscillation: the movement perception was enhanced when the head was kept turned toward the side of body rotation and decreased in the opposite direction. Conversely, passive head deviations had no effect on movement perception. Further, vibration (100 Hz) of the neck muscles splenius capitis and sternocleidomastoideus remarkably influenced perceived rotation during asymmetric oscillation. On the other hand, SPEP of VOR was modulated by active head deviation, but was not influenced by neck muscle vibration. Through its effects on motion perception and reflex gain, head position improved gaze stability and enhanced self-motion perception in the direction of the head deviation. Copyright © 2010 Elsevier B.V. All rights reserved.

Bearings Only Tracking with Fusion from Heterogenous Passive Sensors: ESM/EO and Acoustic

DTIC Science & Technology

2017-02-01

consists of an unscented Kalman filter (UKF) to handle in-sequence ESM/EO measurements and an OOSM unscented Gauss-Helmert filter (OOSM-UGHF) to handle out...bearings-only tracking, target motion analysis, unscented Gauss-Helmert filter , out-of-sequence measurement. I. INTRODUCTION The commonly used passive...proposed an unscented Gauss-Helmert filter (UGHF) [22] [21] to solve this problem. The existing UGHF works with in-sequence measurements. Further

Ranging and Correlating Sensor Development Program.

DTIC Science & Technology

1983-11-01

environmental or man-made disturbance that imparts motion within the protected area. Examples include air turbulence, rotating or oscillating objects such as fans...passive magnetic, passive thermal, etc. All fiber- optic transducers may be categorized into either amplitude or phase (interferometric) types. In an...equivalent phase shifts of less than +/- 1800 for any target. The wavelength of a 20 kHz carrier in air is about 0.68 inches; at 50 kHz the wavelength is about

26 CFR 1.469-3T - Passive activity credit (temporary).

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 6 2010-04-01 2010-04-01 false Passive activity credit (temporary). 1.469-3T... TAX (CONTINUED) INCOME TAXES Taxable Year for Which Deductions Taken § 1.469-3T Passive activity credit (temporary). (a) Computation of passive activity credit. The taxpayer's passive activity credit...

Nicolaus Taurellus on forms and elements.

PubMed

Blank, Andreas

2014-12-01

This article examines the conception of elements in the natural philosophy of Nicolaus Taurellus (1547-1606) and explores the theological motivation that stands behind this conception. By some of his early modern readers, Taurellus may have been understood as a proponent of material atoms. By contrast, I argue that considerations concerning the substantiality of the ultimate constituents of composites led Taurellus to an immaterialist ontology, according to which elements are immaterial forms that possess active and passive potencies as well as motion and extension. In Taurellus's view, immaterialism about elements provides support for the theological doctrine of creation ex nihilo. As he argues, the ontology of immaterial forms helps to explicate a sense in which creatures are substances, not accidents of the divine substance. In particular, he maintains that immaterial forms stand in suitable relations of ontological dependence to God: creation dependence (since forms would not exist without the divine act of creation), but neither subsistence dependence (since forms continue to exist without continued divine agency) nor activity dependence (since forms are active without requiring divine concurrence).

Temporal Characteristics of Radiologists' and Novices' Lesion Detection in Viewing Medical Images Presented Rapidly and Sequentially.

PubMed

Nakashima, Ryoichi; Komori, Yuya; Maeda, Eriko; Yoshikawa, Takeharu; Yokosawa, Kazuhiko

2016-01-01

Although viewing multiple stacks of medical images presented on a display is a relatively new but useful medical task, little is known about this task. Particularly, it is unclear how radiologists search for lesions in this type of image reading. When viewing cluttered and dynamic displays, continuous motion itself does not capture attention. Thus, it is effective for the target detection that observers' attention is captured by the onset signal of a suddenly appearing target among the continuously moving distractors (i.e., a passive viewing strategy). This can be applied to stack viewing tasks, because lesions often show up as transient signals in medical images which are sequentially presented simulating a dynamic and smoothly transforming image progression of organs. However, it is unclear whether observers can detect a target when the target appears at the beginning of a sequential presentation where the global apparent motion onset signal (i.e., signal of the initiation of the apparent motion by sequential presentation) occurs. We investigated the ability of radiologists to detect lesions during such tasks by comparing the performances of radiologists and novices. Results show that overall performance of radiologists is better than novices. Furthermore, the temporal locations of lesions in CT image sequences, i.e., when a lesion appears in an image sequence, does not affect the performance of radiologists, whereas it does affect the performance of novices. Results indicate that novices have greater difficulty in detecting a lesion appearing early than late in the image sequence. We suggest that radiologists have other mechanisms to detect lesions in medical images with little attention which novices do not have. This ability is critically important when viewing rapid sequential presentations of multiple CT images, such as stack viewing tasks.

Temporal Characteristics of Radiologists' and Novices' Lesion Detection in Viewing Medical Images Presented Rapidly and Sequentially

PubMed Central

Nakashima, Ryoichi; Komori, Yuya; Maeda, Eriko; Yoshikawa, Takeharu; Yokosawa, Kazuhiko

2016-01-01

Although viewing multiple stacks of medical images presented on a display is a relatively new but useful medical task, little is known about this task. Particularly, it is unclear how radiologists search for lesions in this type of image reading. When viewing cluttered and dynamic displays, continuous motion itself does not capture attention. Thus, it is effective for the target detection that observers' attention is captured by the onset signal of a suddenly appearing target among the continuously moving distractors (i.e., a passive viewing strategy). This can be applied to stack viewing tasks, because lesions often show up as transient signals in medical images which are sequentially presented simulating a dynamic and smoothly transforming image progression of organs. However, it is unclear whether observers can detect a target when the target appears at the beginning of a sequential presentation where the global apparent motion onset signal (i.e., signal of the initiation of the apparent motion by sequential presentation) occurs. We investigated the ability of radiologists to detect lesions during such tasks by comparing the performances of radiologists and novices. Results show that overall performance of radiologists is better than novices. Furthermore, the temporal locations of lesions in CT image sequences, i.e., when a lesion appears in an image sequence, does not affect the performance of radiologists, whereas it does affect the performance of novices. Results indicate that novices have greater difficulty in detecting a lesion appearing early than late in the image sequence. We suggest that radiologists have other mechanisms to detect lesions in medical images with little attention which novices do not have. This ability is critically important when viewing rapid sequential presentations of multiple CT images, such as stack viewing tasks. PMID:27774080

ULTRASOUND MEASUREMENTS AND OBJECTIVE FORCES OF GLENOHUMERAL TRANSLATIONS DURING SHOULDER ACCESSORY PASSIVE MOTION TESTING IN HEALTHY INDIVIDUALS

PubMed Central

Worst, Haley; Decarreau, Ryan; Davies, George

2016-01-01

Background Clinical examination of caspuloligamentous structures of the glenohumeral joint has historically been subjective in nature, as demonstrated by limited intra-rater and inter-rater reproducibility. Musculoskeletal diagnostic ultrasound was utilized to develop a clinically objective measurement technique for glenohumeral inferior and posterolateral translation. Purpose The purpose of this study was to measure the accessory passive force required to achieve end range glenohumeral posterolateral and inferior accessory translation, as well as, to quantify the amount of translation of the glenohumeral joint caused by the applied force. Study Design Cross-sectional descriptive correlational study Methods Twenty-five asymptomatic subjects between the ages of 18 and 30 were recruited via convenience sampling. Posterolateral and inferior shoulder accessory passive translation was assessed and measured using a GE LOGIQe ultrasound, while concurrently using a hand held dynamometer to quantify the passive force applied during assessment. Normative values for force and translation were described as means and standard deviations. Results Mean values for posterolateral translation were 6.5 +/− 4.0 mm on the right shoulder and 6.3 +/− 3.5 mm on the left with an associated mean force of 127.1 +/− 55.6 N and 114.4 +/− 50.7 N, respectively. Mean values for inferior translation were 4.8 +/− 1.7 mm on the right shoulder and 5.4 +/− 1.8 mm on the left with an associated mean force of 84.5 +/− 30.5 N and 76.1 +/− 30.1 N, respectively. There was a significant association between inferior translation and inferior force (r = .51). No significant association was found between posterolateral translation and posterolateral force. Significant differences were found between dominant and non-dominant shoulders for posterolateral translation, posterolateral force to produce translation, and inferior translation values. Conclusions Force data in the posterolateral and inferior direction is consistent with previously reported data for passive accessory motion testing at the shoulder. The results of this study provide data for glenohumeral translations and actual forces applied. Musculoskeletal diagnostic ultrasound can be a clinically relevant way to objectively measure the translation of the glenohumeral joint for assessing accessory passive motion joint translation while performing mobilizations or passive structure testing. This study provides a basis for comparison for healthy shoulder joints. Level of Evidence 2b PMID:27757287

Continuous-flow cold therapy for outpatient anterior cruciate ligament reconstruction.

PubMed

Barber, F A; McGuire, D A; Click, S

1998-03-01

This prospective, randomized study evaluated continuous-flow cold therapy for postoperative pain in outpatient arthroscopic anterior cruciate ligament (ACL) reconstructions. In group 1, cold therapy was constant for 3 days then as needed in days 4 through 7. Group 2 had no cold therapy. Evaluations and diaries were kept at 1, 2, and 8 hours after surgery, and then daily. Pain was assessed using the VAS and Likert scales. There were 51 cold and 49 noncold patients included. Continuous passive movement (CPM) use averaged 54 hours for cold and 41 hours for noncold groups (P=.003). Prone hangs were done for 192 minutes in the cold group and 151 minutes in the noncold group. Motion at 1 week averaged 5/88 for the cold group and 5/79 the noncold group. The noncold group average visual analog scale (VAS) pain and Likert pain scores were always greater than the cold group. The noncold group average Vicodin use (Knoll, Mt. Olive, NJ) was always greater than the cold group use (P=.001). Continuous-flow cold therapy lowered VAS and Likert scores, reduced Vicodin use, increased prone hangs, CPM, and knee flexion. Continuous-flow cold therapy is safe and effective for outpatient ACL reconstruction reducing pain medication requirements.

Can the self-propulsion of anisotropic microswimmers be described by using forces and torques?

NASA Astrophysics Data System (ADS)

ten Hagen, Borge; Wittkowski, Raphael; Takagi, Daisuke; Kümmel, Felix; Bechinger, Clemens; Löwen, Hartmut

2015-05-01

The self-propulsion of artificial and biological microswimmers (or active colloidal particles) has often been modelled by using a force and a torque entering into the overdamped equations for the Brownian motion of passive particles. This seemingly contradicts the fact that a swimmer is force-free and torque-free, i.e. that the net force and torque on the particle vanish. Using different models for mechanical and diffusiophoretic self-propulsion, we demonstrate here that the equations of motion of microswimmers can be mapped onto those of passive particles with the shape-dependent grand resistance matrix and formally external effective forces and torques. This is consistent with experimental findings on the circular motion of artificial asymmetric microswimmers driven by self-diffusiophoresis. The concept of effective self-propulsion forces and torques significantly facilitates the understanding of the swimming paths, e.g. for a microswimmer under gravity. However, this concept has its limitations when the self-propulsion mechanism of a swimmer is disturbed either by another particle in its close vicinity or by interactions with obstacles, such as a wall.

Obstacle-avoiding robot with IR and PIR motion sensors

NASA Astrophysics Data System (ADS)

Ismail, R.; Omar, Z.; Suaibun, S.

2016-10-01

Obstacle avoiding robot was designed, constructed and programmed which may be potentially used for educational and research purposes. The developed robot will move in a particular direction once the infrared (IR) and the PIR passive infrared (PIR) sensors sense a signal while avoiding the obstacles in its path. The robot can also perform desired tasks in unstructured environments without continuous human guidance. The hardware was integrated in one application board as embedded system design. The software was developed using C++ and compiled by Arduino IDE 1.6.5. The main objective of this project is to provide simple guidelines to the polytechnic students and beginners who are interested in this type of research. It is hoped that this robot could benefit students who wish to carry out research on IR and PIR sensors.

Shoulder rotational profiles in young healthy elite female and male badminton players.

PubMed

Couppé, C; Thorborg, K; Hansen, M; Fahlström, M; Bjordal, J M; Nielsen, D; Baun, M; Storgaard, M; Magnusson, S P

2014-02-01

The aim of the present study was to profile shoulder passive range of motion (ROM) and isometric strength for external (ER) and internal (IR) rotation as part of a preseason screening in adolescent national badminton players. Passive external range of motion (EROM) and internal range of motion (IROM) were examined on the dominant and nondominant shoulder in 31 adolescent national badminton players (12 females and 19 males) with a standard goniometer. Muscle strength was examined with a hand-held dynamometer in ER and IR. Total range of motion (TROM = EROM+IROM) was lower on the dominant side compared with the nondominant side in both groups (P < 0.001). Males were generally stronger than females in all strength measurements except for IR on the dominant side (P < 0.01). In females, IR dominant side strength was greater compared with IR on the nondominant side (P < 0.05). TROM was reduced on the dominant side compared with the nondominant side in young elite badminton players, irrespective of gender. No rotational strength differences existed between the dominant and nondominant side in male players, but in female players a higher IR strength on the dominant side was not balanced by a higher ER strength. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dependence of muscle moment arms on in-vivo three-dimensional kinematics of the knee

PubMed Central

Navacchia, Alessandro; Kefala, Vasiliki; Shelburne, Kevin B.

2016-01-01

Quantification of muscle moment arms is important for clinical evaluation of muscle pathology and treatment, and for estimating muscle and joint forces in musculoskeletal models. Moment arms estimated with musculoskeletal models often assume a default motion of the knee derived from measurements of passive cadaveric flexion. However, knee kinematics are unique to each person and activity. The objective of this study was to estimate moment arms of the knee muscles with in vivo subject- and activity-specific kinematics from seven healthy subjects performing seated knee extension and single-leg lunge to show changes between subjects and activities. 3D knee motion was measured with a high-speed stereo-radiography system. Moment arms of ten muscles were estimated in OpenSim by replacing the default knee motion with in vivo measurements. Estimated inter-subject moment arm variability was similar to previously reported in vitro measurements. RMS deviations up to 9.0 mm (35.2% of peak value) were observed between moment arms estimated with subject-specific knee extension and passive cadaveric motion. The degrees of freedom that most impacted inter-activity differences were superior/inferior and anterior/posterior translations. Musculoskeletal simulations used to estimate in vivo muscle forces and joint loads may provide significantly different results when subject- and activity-specific kinematics are implemented. PMID:27620064

Dependence of Muscle Moment Arms on In Vivo Three-Dimensional Kinematics of the Knee.

PubMed

Navacchia, Alessandro; Kefala, Vasiliki; Shelburne, Kevin B

2017-03-01

Quantification of muscle moment arms is important for clinical evaluation of muscle pathology and treatment, and for estimating muscle and joint forces in musculoskeletal models. Moment arms estimated with musculoskeletal models often assume a default motion of the knee derived from measurements of passive cadaveric flexion. However, knee kinematics are unique to each person and activity. The objective of this study was to estimate moment arms of the knee muscles with in vivo subject- and activity-specific kinematics from seven healthy subjects performing seated knee extension and single-leg lunge to show changes between subjects and activities. 3D knee motion was measured with a high-speed stereo-radiography system. Moment arms of ten muscles were estimated in OpenSim by replacing the default knee motion with in vivo measurements. Estimated inter-subject moment arm variability was similar to previously reported in vitro measurements. RMS deviations up to 9.0 mm (35.2% of peak value) were observed between moment arms estimated with subject-specific knee extension and passive cadaveric motion. The degrees of freedom that most impacted inter-activity differences were superior/inferior and anterior/posterior translations. Musculoskeletal simulations used to estimate in vivo muscle forces and joint loads may provide significantly different results when subject- and activity-specific kinematics are implemented.

Influence of the noise sources motion on the estimated Green's functions from ambient noise cross-correlations.

PubMed

Sabra, Karim G

2010-06-01

It has been demonstrated theoretically and experimentally that an estimate of the Green's function between two receivers can be obtained by cross-correlating acoustic (or elastic) ambient noise recorded at these two receivers. Coherent wavefronts emerge from the noise cross-correlation time function due to the accumulated contributions over time from noise sources whose propagation path pass through both receivers. Previous theoretical studies of the performance of this passive imaging technique have assumed that no relative motion between noise sources and receivers occurs. In this article, the influence of noise sources motion (e.g., aircraft or ship) on this passive imaging technique was investigated theoretically in free space, using a stationary phase approximation, for stationary receivers. The theoretical results were extended to more complex environments, in the high-frequency regime, using first-order expansions of the Green's function. Although sources motion typically degrades the performance of wideband coherent processing schemes, such as time-delay beamforming, it was found that the Green's function estimated from ambient noise cross-correlations are not expected to be significantly affected by the Doppler effect, even for supersonic sources. Numerical Monte-Carlo simulations were conducted to confirm these theoretical predictions for both cases of subsonic and supersonic moving sources.

Lumbar contribution to the trunk forward bending and backward return; age-related differences.

PubMed

Vazirian, Milad; Shojaei, Iman; Agarwal, Anuj; Bazrgari, Babak

2017-07-01

Age-related differences in lumbar contribution to the trunk motion in the sagittal plane were investigated. Sixty individuals between 20-70 years old in five gender-balanced age groups performed forward bending and backward return with slow and fast paces. Individuals older than 50 years old, irrespective of the gender or pace, had smaller lumbar contribution than those younger than this age. The lumbar contribution to trunk motion was also smaller in female participants than male participants, and under fast pace than under the slow pace. Age-related differences in lumbar contributions suggest the synergy between the active and passive lower back tissues is different between those above and under 50 years old, differences that are likely to affect the lower back mechanics. Therefore, detailed modelling should be conducted in future to find the age-related differences in the lower back mechanics for tasks involving large trunk motion. Practitioner Summary: Lumbar contribution to the sagittal trunk motion was observed to be smaller in individuals above 50 years old than those below this age. This could be an indication of a likely change in the synergy between the active and passive lower back tissues, which may disturb the lower back mechanics.

Computational Knee Ligament Modeling Using Experimentally Determined Zero-Load Lengths

PubMed Central

Bloemker, Katherine H; Guess, Trent M; Maletsky, Lorin; Dodd, Kevin

2012-01-01

This study presents a subject-specific method of determining the zero-load lengths of the cruciate and collateral ligaments in computational knee modeling. Three cadaver knees were tested in a dynamic knee simulator. The cadaver knees also underwent manual envelope of motion testing to find their passive range of motion in order to determine the zero-load lengths for each ligament bundle. Computational multibody knee models were created for each knee and model kinematics were compared to experimental kinematics for a simulated walk cycle. One-dimensional non-linear spring damper elements were used to represent cruciate and collateral ligament bundles in the knee models. This study found that knee kinematics were highly sensitive to altering of the zero-load length. The results also suggest optimal methods for defining each of the ligament bundle zero-load lengths, regardless of the subject. These results verify the importance of the zero-load length when modeling the knee joint and verify that manual envelope of motion measurements can be used to determine the passive range of motion of the knee joint. It is also believed that the method described here for determining zero-load length can be used for in vitro or in vivo subject-specific computational models. PMID:22523522

49 CFR 178.274 - Specifications for UN portable tanks.

Code of Federal Regulations, 2011 CFR

2011-10-01

... transported; or (ii) Properly passivated or neutralized by chemical reaction, if applicable; or (iii) For.... All stop-valves with screwed spindles must close by a clockwise motion of the handwheel. For other...

Anomalous scaling of a scalar field advected by turbulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraichnan, R.H.

Recent work leading to deduction of anomalous scaling exponents for the inertial range of an advected passive field from the equations of motion is reviewed. Implications for other turbulence problems are discussed.

Multisensory integration in early vestibular processing in mice: the encoding of passive vs. active motion

PubMed Central

Medrea, Ioana

2013-01-01

The mouse has become an important model system for studying the cellular basis of learning and coding of heading by the vestibular system. Here we recorded from single neurons in the vestibular nuclei to understand how vestibular pathways encode self-motion under natural conditions, during which proprioceptive and motor-related signals as well as vestibular inputs provide feedback about an animal's movement through the world. We recorded neuronal responses in alert behaving mice focusing on a group of neurons, termed vestibular-only cells, that are known to control posture and project to higher-order centers. We found that the majority (70%, n = 21/30) of neurons were bimodal, in that they responded robustly to passive stimulation of proprioceptors as well as passive stimulation of the vestibular system. Additionally, the linear summation of a given neuron's vestibular and neck sensitivities predicted well its responses when both stimuli were applied simultaneously. In contrast, neuronal responses were suppressed when the same motion was actively generated, with the one striking exception that the activity of bimodal neurons similarly and robustly encoded head on body position in all conditions. Our results show that proprioceptive and motor-related signals are combined with vestibular information at the first central stage of vestibular processing in mice. We suggest that these results have important implications for understanding the multisensory integration underlying accurate postural control and the neural representation of directional heading in the head direction cell network of mice. PMID:24089394

Brainstem processing of vestibular sensory exafference: implications for motion sickness etiology

PubMed Central

Oman, Charles M.; Cullen, Kathleen E.

2014-01-01

The origin of the internal “sensory conflict” stimulus causing motion sickness has been debated for more than four decades. Recent studies show a subclass of neurons in the vestibular nuclei and deep cerebellar nuclei that respond preferentially to passive head movements. During active movement, the semicircular canal and otolith input (“reafference”) to these neurons is cancelled by a mechanism comparing the expected consequences of self-generated movement (estimated with an internal model-presumably located in the cerebellum) with the actual sensory feedback. The un-cancelled component (“exafference”) resulting from passive movement normally helps compensate for unexpected postural disturbances. Notably, the existence of such vestibular “sensory conflict” neurons had been postulated as early as 1982, but their existence and putative role in posture control, motion sickness has been long debated. Here we review the development of “sensory conflict” theories in relation to recent evidence for brainstem and cerebellar reafference cancellation, and identify some open research questions. We propose that conditions producing persistent activity of these neurons, or their targets, stimulates nearby brainstem emetic centers – via an as yet unidentified mechanism. We discuss how such a mechanism is consistent with the notable difference in motion sickness susceptibility of drivers as opposed to passengers, human immunity to normal self-generated movement, and why head restraint or lying horizontal confers relative immunity. Finally, we propose that fuller characterization of these mechanisms, and their potential role in motion sickness could lead to more effective, scientifically based prevention and treatment for motion sickness. PMID:24838552

Dynamics of Fractal Cluster Gels with Embedded Active Colloids

NASA Astrophysics Data System (ADS)

Szakasits, Megan E.; Zhang, Wenxuan; Solomon, Michael J.

2017-08-01

We find that embedded active colloids increase the ensemble-averaged mean squared displacement of particles in otherwise passively fluctuating fractal cluster gels. The enhancement in dynamics occurs by a mechanism in which the active colloids contribute to the average dynamics both directly through their own active motion and indirectly through their excitation of neighboring passive colloids in the fractal network. Fractal cluster gels are synthesized by addition of magnesium chloride to an initially stable suspension of 1.0 μ m polystyrene colloids in which a dilute concentration of platinum coated Janus colloids has been dispersed. The Janus colloids are thereby incorporated into the fractal network. We measure the ensemble-averaged mean squared displacement of all colloids in the gel before and after the addition of hydrogen peroxide, a fuel that drives diffusiophoretic motion of the Janus particles. The gel mean squared displacement increases by up to a factor of 3 for an active to passive particle ratio of 1 ∶20 and inputted active energy—defined based on the hydrogen peroxide's effect on colloid swim speed and run length—that is up to 9.5 times thermal energy, on a per particle basis. We model the enhancement in gel particle dynamics as the sum of a direct contribution from the displacement of the Janus particles themselves and an indirect contribution from the strain field that the active colloids induce in the surrounding passive particles.

Techniques for active passivation

DOEpatents

Roscioli, Joseph R.; Herndon, Scott C.; Nelson, Jr., David D.

2016-12-20

In one embodiment, active (continuous or intermittent) passivation may be employed to prevent interaction of sticky molecules with interfaces inside of an instrument (e.g., an infrared absorption spectrometer) and thereby improve response time. A passivation species may be continuously or intermittently applied to an inlet of the instrument while a sample gas stream is being applied. The passivation species may have a highly polar functional group that strongly binds to either water or polar groups of the interfaces, and once bound presents a non-polar group to the gas phase in order to prevent further binding of polar molecules. The instrument may be actively used to detect the sticky molecules while the passivation species is being applied.

26 CFR 1.469-2 - Passive activity loss.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 6 2011-04-01 2011-04-01 false Passive activity loss. 1.469-2 Section 1.469-2...) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-2 Passive activity loss. (a)-(c... passive activity unless the interest in property was used in a passive activity for either— (1) 20 percent...

Correlations between ankle-foot impairments and dropped foot gait deviations among stroke survivors.

PubMed

Chisholm, Amanda E; Perry, Stephen D; McIlroy, William E

2013-01-01

The purpose of this paper is to 1) evaluate the relationship between ankle kinematics during gait and standardized measures of ankle impairments among sub-acute stroke survivors, and 2) compare the degree of stroke-related ankle impairment between individuals with and without dropped foot gait deviations. Fifty-five independently ambulating stroke survivors participated in this study. Dropped foot was defined as decreased peak dorsiflexion during the swing phase and reduced ankle joint motion in stance. Standardized outcome measures included the Chedoke-McMaster Stroke Assessment (motor impairment), Modified Ashworth Scale (spasticity), Medical Research Council (muscle strength), passive and active range of motion, and isometric muscle force. Foot impairment was not related to peak dorsiflexion during swing (r=-0.17, P=0.247) and joint motion during stance (r=0.05, P=0.735). Active (r=0.45, P<0.001) and passive (r=0.48, P<0.001) range of motion was associated with stance phase joint motion. Peak dorsiflexion during swing was related to isometric dorsiflexor muscle force (r=-0.32, P=0.039). Individuals with dropped foot demonstrated greater motor impairment, plantarflexor spasticity and ankle muscle weakness compared to those without dropped foot. Our investigation suggests that ankle-foot impairments are related to ankle deviations during gait, as indicated by greater impairment among individuals with dropped foot. These findings contribute to a better understanding of gait-specific ankle deviations, and may lead to the development of a more effective clinical assessment of dropped foot impairment. © 2013.

Controlled motion in an elastic world. Research project: Manipulation strategies for massive space payloads

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1992-01-01

The flexibility of the drives and structures of controlled motion systems are presented as an obstacle to be overcome in the design of high performance motion systems, particularly manipulator arms. The task and the measure of performance to be applied determine the technology appropriate to overcome this obstacle. Included in the technologies proposed are control algorithms (feedback and feed forward), passive damping enhancement, operational strategies, and structural design. Modeling of the distributed, nonlinear system is difficult, and alternative approaches are discussed. The author presents personal perspectives on the history, status, and future directions in this area.

Spin Stabilized Impulsively Controlled Missile (SSICM)

NASA Astrophysics Data System (ADS)

Crawford, J. I.; Howell, W. M.

1985-12-01

This patent is for the Spin Stabilized Impulsively Controlled Missile (SSICM). SSICM is a missile configuration which employs spin stabilization, nutational motion, and impulsive thrusting, and a body mounted passive or semiactive sensor to achieve very small miss distances against a high speed moving target. SSICM does not contain an autopilot, control surfaces, a control actuation system, nor sensor stabilization gimbals. SSICM spins at a rate sufficient to provide frequency separation between body motions and inertial target motion. Its impulsive thrusters provide near instantaneous changes in lateral velocity, whereas conventional missiles require a significant time delay to achieve lateral acceleration.

Self-motion perception: assessment by real-time computer-generated animations

NASA Technical Reports Server (NTRS)

Parker, D. E.; Phillips, J. O.

2001-01-01

We report a new procedure for assessing complex self-motion perception. In three experiments, subjects manipulated a 6 degree-of-freedom magnetic-field tracker which controlled the motion of a virtual avatar so that its motion corresponded to the subjects' perceived self-motion. The real-time animation created by this procedure was stored using a virtual video recorder for subsequent analysis. Combined real and illusory self-motion and vestibulo-ocular reflex eye movements were evoked by cross-coupled angular accelerations produced by roll and pitch head movements during passive yaw rotation in a chair. Contrary to previous reports, illusory self-motion did not correspond to expectations based on semicircular canal stimulation. Illusory pitch head-motion directions were as predicted for only 37% of trials; whereas, slow-phase eye movements were in the predicted direction for 98% of the trials. The real-time computer-generated animations procedure permits use of naive, untrained subjects who lack a vocabulary for reporting motion perception and is applicable to basic self-motion perception studies, evaluation of motion simulators, assessment of balance disorders and so on.

Uncertainty Prediction in Passive Target Motion Analysis

DTIC Science & Technology

2016-05-12

fundamental property of bearings- only target motion analysis (TMA) is that bearing B to the Attorney Docket No. 300118 3 of 25 target 10 results...the measurements used to estimate them are often non-linear. This is true for the bearing observation: = tan −1 ( () () ) ( 3 ...Parameter Evaluation Plot ( PEP ) is one example of such a grid-based approach. U.S. Patent No. 7,020,046 discloses one version of this method and is

26 CFR 1.1398-1 - Treatment of passive activity losses and passive activity credits in individuals' title 11 cases.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 11 2011-04-01 2011-04-01 false Treatment of passive activity losses and passive activity credits in individuals' title 11 cases. 1.1398-1 Section 1.1398-1 Internal Revenue... (CONTINUED) Rules Relating to Individuals' Title 11 Cases § 1.1398-1 Treatment of passive activity losses and...

Motion correction for passive radiation imaging of small vessels in ship-to-ship inspections

NASA Astrophysics Data System (ADS)

Ziock, K. P.; Boehnen, C. B.; Ernst, J. M.; Fabris, L.; Hayward, J. P.; Karnowski, T. P.; Paquit, V. C.; Patlolla, D. R.; Trombino, D. G.

2016-01-01

Passive radiation detection remains one of the most acceptable means of ascertaining the presence of illicit nuclear materials. In maritime applications it is most effective against small to moderately sized vessels, where attenuation in the target vessel is of less concern. Unfortunately, imaging methods that can remove source confusion, localize a source, and avoid other systematic detection issues cannot be easily applied in ship-to-ship inspections because relative motion of the vessels blurs the results over many pixels, significantly reducing system sensitivity. This is particularly true for the smaller watercraft, where passive inspections are most valuable. We have developed a combined gamma-ray, stereo visible-light imaging system that addresses this problem. Data from the stereo imager are used to track the relative location and orientation of the target vessel in the field of view of a coded-aperture gamma-ray imager. Using this information, short-exposure gamma-ray images are projected onto the target vessel using simple tomographic back-projection techniques, revealing the location of any sources within the target. The complex autonomous tracking and image reconstruction system runs in real time on a 48-core workstation that deploys with the system.

Motion correction for passive radiation imaging of small vessels in ship-to-ship inspections

DOE PAGES

Ziock, Klaus -Peter; Boehnen, Chris Bensing; Ernst, Joseph M.; ...

2015-09-05

Passive radiation detection remains one of the most acceptable means of ascertaining the presence of illicit nuclear materials. In maritime applications it is most effective against small to moderately sized vessels, where attenuation in the target vessel is of less concern. Unfortunately, imaging methods that can remove source confusion, localize a source, and avoid other systematic detection issues cannot be easily applied in ship-to-ship inspections because relative motion of the vessels blurs the results over many pixels, significantly reducing system sensitivity. This is particularly true for the smaller watercraft, where passive inspections are most valuable. We have developed a combinedmore » gamma-ray, stereo visible-light imaging system that addresses this problem. Data from the stereo imager are used to track the relative location and orientation of the target vessel in the field of view of a coded-aperture gamma-ray imager. Using this information, short-exposure gamma-ray images are projected onto the target vessel using simple tomographic back-projection techniques, revealing the location of any sources within the target. Here,the complex autonomous tracking and image reconstruction system runs in real time on a 48-core workstation that deploys with the system.« less

SU-E-T-622: Planning Technique for Passively-Scattered Involved-Node Proton Therapy of Mediastinal Lymphoma with Consideration of Cardiac Motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flampouri, S; Li, Z; Hoppe, B

2015-06-15

Purpose: To develop a treatment planning method for passively-scattered involved-node proton therapy of mediastinal lymphoma robust to breathing and cardiac motions. Methods: Beam-specific planning treatment volumes (bsPTV) are calculated for each proton field to incorporate pertinent uncertainties. Geometric margins are added laterally to each beam while margins for range uncertainty due to setup errors, breathing, and calibration curve uncertainties are added along each beam. The calculation of breathing motion and deformation effects on proton range includes all 4DCT phases. The anisotropic water equivalent margins are translated to distances on average 4DCT. Treatment plans are designed so each beam adequately coversmore » the corresponding bsPTV. For targets close to the heart, cardiac motion effects on dosemaps are estimated by using a library of anonymous ECG-gated cardiac CTs (cCT). The cCT, originally contrast-enhanced, are partially overridden to allow meaningful proton dose calculations. Targets similar to the treatment targets are drawn on one or more cCT sets matching the anatomy of the patient. Plans based on the average cCT are calculated on individual phases, then deformed to the average and accumulated. When clinically significant dose discrepancies occur between planned and accumulated doses, the patient plan is modified to reduce the cardiac motion effects. Results: We found that bsPTVs as planning targets create dose distributions similar to the conventional proton planning distributions, while they are a valuable tool for visualization of the uncertainties. For large targets with variability in motion and depth, integral dose was reduced because of the anisotropic margins. In most cases, heart motion has a clinically insignificant effect on target coverage. Conclusion: A treatment planning method was developed and used for proton therapy of mediastinal lymphoma. The technique incorporates bsPTVs compensating for all common sources of uncertainties and estimation of the effects of cardiac motion not commonly performed.« less

Impact of 10-Minute Interval Roller Massage on Performance and Active Range of Motion.

PubMed

Hodgson, D D; Quigley, P J; Whitten, J H D; Reid, J C; Behm, David G

2017-11-16

Hodgson, DD, Quigley, PJ, Whitten, JHD, Reid, JC, and Behm, DG. Impact of 10-minute interval roller massage on performance and active range of motion. J Strength Cond Res XX(X): 000-000, 2017-Roller massage (RM) has been shown to increase range of motion (ROM) without subsequent performance deficits. However, prolonged static stretching (SS) can induce performance impairments. The objective of this study was to examine the effects of combining SS and RM with and without subsequent RM on ROM and neuromuscular performance. Subjects (n = 12) participated in 5 sessions: (a) SS only (SS_rest), (b) SS + RM (SS + RM_rest), (c) SS with RM at 10 and 20 minutes after stretch (SS_RM), (d) SS + RM with RM at 10 and 20 minutes after stretch (SS + RM_RM), and (e) control. For the SS conditions, the quadriceps and hamstrings received passive SS for 2 × 30 seconds each. For the SS + RM conditions, SS was applied to the quadriceps and hamstrings for 30 seconds each, and RM was performed for 30 seconds per muscle. SS_RM and SS + RM_RM conditions received an additional 30-second RM at 10 and 20 minutes after warm-up, whereas sessions without additional RM rested for the same duration. Testing measures included hip flexion (HF) and knee flexion (KF) active and passive ROM, hurdle jump height and contact time, countermovement jump height, and maximal voluntary isometric contraction force. Initial KF and HF ROM improvements provided by SS_RM and SS + RM_RM were sustained up to 30 minutes after intervention. Furthermore, SS_RM exhibited greater ROM compared with sessions lacking additional RM in active and passive HF as well as active and passive KF. Similarly, SS + RM_RM elicited greater KF and HF ROM improvements than SS_rest. In conclusion, active KF and HF ROM improvements were prolonged by additional RM, whereas neuromuscular performance remained relatively unaffected.

Influence of Passive Muscle Tension on Electromechanical Delay in Humans

PubMed Central

Lacourpaille, Lilian; Hug, François; Nordez, Antoine

2013-01-01

Background Electromechanical delay is the time lag between onsets of muscle activation and muscle force production and reflects both electro-chemical processes and mechanical processes. The aims of the present study were two-fold: to experimentally determine the slack length of each head of the biceps brachii using elastography and to determine the influence of the length of biceps brachii on electromechanical delay and its electro-chemical/mechanical processes using very high frame rate ultrasound. Methods/Results First, 12 participants performed two passive stretches to evaluate the change in passive tension for each head of the biceps brachii. Then, they underwent two electrically evoked contractions from 120 to 20° of elbow flexion (0°: full extension), with the echographic probe maintained over the muscle belly and the myotendinous junction of biceps brachii. The slack length was found to occur at 95.5 ± 6.3° and 95.3 ± 8.2° of the elbow joint angle for the long and short heads of the biceps brachii, respectively. The electromechanical delay was significantly longer at 120° (16.9 ± 3.1 ms; p<0.001), 110° (15.0 ± 3.1 ms; p<0.001) and 100° (12.7 ± 2.5 ms; p = 0.01) of elbow joint angle compared to 90° (11.1 ± 1.7 ms). However, the delay between the onset of electrical stimulation and the onset of both muscle fascicles (3.9 ± 0.2 ms) and myotendinous junction (3.7 ± 0.3 ms) motion was not significantly affected by the joint angle (p>0.95). Conclusion In contrast to previous observations on gastrocnemius medialis, the onset of muscle motion and the onset of myotendinous junction motion occurred simultaneously regardless of the length of the biceps brachii. That suggests that the between-muscles differences reported in the literature cannot be explained by different muscle passive tension but instead may be attributable to muscle architectural differences. PMID:23308153

Wing motion transformation to evaluate aerodynamic coupling in flapping wing flight.

PubMed

Faruque, Imraan A; Humbert, J Sean

2014-12-21

Whether the remarkable flight performance of insects is because the animals leverage inherent physics at this scale or because they employ specialized neural feedback mechanisms is an active research question. In this study, an empirically derived aerodynamics model is used with a transformation involving a delay and a rotation to identify a class of kinematics that provide favorable roll-yaw coupling. The transformation is also used to transform both synthetic and experimentally measured wing motions onto the manifold representing proverse yaw and to quantify the degree to which freely flying insects make use of passive aerodynamic mechanisms to provide proverse roll-yaw turn coordination. The transformation indicates that recorded insect kinematics do act to provide proverse yaw for a variety of maneuvers. This finding suggests that passive aerodynamic mechanisms can act to reduce the neural feedback demands of an insect׳s flight control strategy. Copyright © 2014 Elsevier Ltd. All rights reserved.

International Network of Passive Correlation Ranging for Orbit Determination of a Geostationary Satellite

NASA Astrophysics Data System (ADS)

Kaliuzhnyi, Mykola; Bushuev, Felix; Shulga, Oleksandr; Sybiryakova, Yevgeniya; Shakun, Leonid; Bezrukovs, Vladislavs; Moskalenko, Sergiy; Kulishenko, Vladislav; Malynovskyi, Yevgen

2016-12-01

An international network of passive correlation ranging of a geostationary telecommunication satellite is considered in the article. The network is developed by the RI "MAO". The network consists of five spatially separated stations of synchronized reception of DVB-S signals of digital satellite TV. The stations are located in Ukraine and Latvia. The time difference of arrival (TDOA) on the network stations of the DVB-S signals, radiated by the satellite, is a measured parameter. The results of TDOA estimation obtained by the network in May-August 2016 are presented in the article. Orbital parameters of the tracked satellite are determined using measured values of the TDOA and two models of satellite motion: the analytical model SGP4/SDP4 and the model of numerical integration of the equations of satellite motion. Both models are realized using the free low-level space dynamics library OREKIT (ORbit Extrapolation KIT).

Intervention for an Adolescent With Cerebral Palsy During Period of Accelerated Growth.

PubMed

Reubens, Rebecca; Silkwood-Sherer, Debbie J

2016-01-01

The purpose of this case report was to describe changes in body functions and structures, activities, and participation after a biweekly 10-week program of home physical therapy and hippotherapy using a weighted compressor belt. A 13-year-old boy with spastic diplegic cerebral palsy, Gross Motor Function Classification System level II, was referred because of accelerated growth and functional impairments that limited daily activities. The Modified Ashworth Scale, passive range of motion, 1-Minute Walk Test, Timed Up and Down Stairs, Pediatric Balance Scale, Pediatric Evaluation of Disability Inventory Computer Adaptive Test, and Dimensions of Mastery Questionnaire 17 were examined at baseline, 5, and 10 weeks. Data at 5 and 10 weeks demonstrated positive changes in passive range of motion, balance, strength, functional activities, and motivation, with additional improvements in endurance and speed after 10 weeks. This report reveals enhanced body functions and structures and activities and improved participation and motivation.

Online attitude determination of a passively magnetically stabilized spacecraft

NASA Astrophysics Data System (ADS)

Burton, R.; Rock, S.; Springmann, J.; Cutler, J.

2017-04-01

An online attitude determination filter is developed for a nano satellite that has no onboard attitude sensors or gyros. Specifically, the attitude of NASA Ames Research Center's O/OREOS, a passively magnetically stabilized 3U CubeSat, is determined using only an estimate of the solar vector obtained from solar panel currents. The filter is based upon the existing multiplicative extended Kalman filter (MEKF) but instead of relying on gyros to drive the motion model, the filter instead incorporates a model of the spacecraft's attitude dynamics in the motion model. An attitude determination accuracy of five degrees is demonstrated, a performance verified using flight data from the University of Michigan's RAX-1. Although the filter was designed for the specific problem of a satellite without gyros or attitude determination it could also be used to provide smoothing of noisy gyro signals or to provide a backup in the event of gyro failures.

A Module for Automatic Dock and Detumble (MADD) for orbital rescue operations

NASA Technical Reports Server (NTRS)

Snow, W. R.; Kunciw, B. G.; Kaplan, M. H.

1973-01-01

The module for automatic dock and detumble (MADD) is an automated device for bringing a passive, tumbling space base under control in an orbital rescue situation. The conceptual design of such a device resulted from a consideration of tumbling motion analyses and mission constraints. Specific topics of investigation include orbit and attitude dynamics and detumble profiles. Position and attitude control systems for the various phases of operation were developed. Dynamic motion of a passive vehicle with MADD attached is considered as an example application and to determine control requirements. Since time is a critical factor in rescue operations, it is essential to execute the detumbling maneuver in a minimum of time. Optimization of the MADD thrusting sequence has also been investigated. Results indicate the control torque must be directed opposite to the angular momentum vector for the assumption used here.

Oscillation of the velvet worm slime jet by passive hydrodynamic instability

PubMed Central

Concha, Andrés; Mellado, Paula; Morera-Brenes, Bernal; Sampaio Costa, Cristiano; Mahadevan, L; Monge-Nájera, Julián

2015-01-01

The rapid squirt of a proteinaceous slime jet endows velvet worms (Onychophora) with a unique mechanism for defence from predators and for capturing prey by entangling them in a disordered web that immobilizes their target. However, to date, neither qualitative nor quantitative descriptions have been provided for this unique adaptation. Here we investigate the fast oscillatory motion of the oral papillae and the exiting liquid jet that oscillates with frequencies f~30–60 Hz. Using anatomical images, high-speed videography, theoretical analysis and a physical simulacrum, we show that this fast oscillatory motion is the result of an elastohydrodynamic instability driven by the interplay between the elasticity of oral papillae and the fast unsteady flow during squirting. Our results demonstrate how passive strategies can be cleverly harnessed by organisms, while suggesting future oscillating microfluidic devices, as well as novel ways for micro and nanofibre production using bioinspired strategies. PMID:25780995

A Large Motion Suspension System for Simulation of Orbital Deployment

NASA Technical Reports Server (NTRS)

Straube, T. M.; Peterson, L. D.

1994-01-01

This paper describes the design and implementation of a vertical degree of freedom suspension system which provides a constant force off-load condition to counter gravity over large displacements. By accommodating motions up to one meter for structures weighing up to 100 pounds, the system is useful for experiments which simulate the on-orbit deployment of spacecraft components. A unique aspect of this system is the combination of a large stroke passive off-load device augmented by electromotive torque actuated force feedback. The active force feedback has the effect of reducing breakaway friction by an order of magnitude over the passive system alone. The paper describes the development of the suspension hardware and the feedback control algorithm. Experiments were performed to verify the suspensions system's ability to provide a gravity off-load as well as its effect on the modal characteristics of a test article.

Simulation Research on Vehicle Active Suspension Controller Based on G1 Method

NASA Astrophysics Data System (ADS)

Li, Gen; Li, Hang; Zhang, Shuaiyang; Luo, Qiuhui

2017-09-01

Based on the order relation analysis method (G1 method), the optimal linear controller of vehicle active suspension is designed. The system of the main and passive suspension of the single wheel vehicle is modeled and the system input signal model is determined. Secondly, the system motion state space equation is established by the kinetic knowledge and the optimal linear controller design is completed with the optimal control theory. The weighting coefficient of the performance index coefficients of the main passive suspension is determined by the relational analysis method. Finally, the model is simulated in Simulink. The simulation results show that: the optimal weight value is determined by using the sequence relation analysis method under the condition of given road conditions, and the vehicle acceleration, suspension stroke and tire motion displacement are optimized to improve the comprehensive performance of the vehicle, and the active control is controlled within the requirements.

Nonlinear flight dynamics and stability of hovering model insects

PubMed Central

Liang, Bin; Sun, Mao

2013-01-01

Current analyses on insect dynamic flight stability are based on linear theory and limited to small disturbance motions. However, insects' aerial environment is filled with swirling eddies and wind gusts, and large disturbances are common. Here, we numerically solve the equations of motion coupled with the Navier–Stokes equations to simulate the large disturbance motions and analyse the nonlinear flight dynamics of hovering model insects. We consider two representative model insects, a model hawkmoth (large size, low wingbeat frequency) and a model dronefly (small size, high wingbeat frequency). For small and large initial disturbances, the disturbance motion grows with time, and the insects tumble and never return to the equilibrium state; the hovering flight is inherently (passively) unstable. The instability is caused by a pitch moment produced by forward/backward motion and/or a roll moment produced by side motion of the insect. PMID:23697714

Influence of scale interaction on the transport of a passive scalar in a turbulent boundary layer

NASA Astrophysics Data System (ADS)

Saxton-Fox, Theresa; Dawson, Scott; McKeon, Beverley

2017-11-01

A mildly heated turbulent boundary layer is experimentally studied using particle image velocimetry to measure the velocity field and a Malley probe (Malley et al., 1992; Gordeyev et al., 2014) to measure the passive scalar field. Strong gradients in the passive scalar field are observed to be correlated to the interaction of specific velocity scales, illuminating an effect of scale interaction on the passive scalar field. A resolvent analysis performed on the fluctuating velocity and passive scalar equations of motion is used to identify the most amplified velocity and scalar mode shapes at particular wavenumbers. The superposition of a small number of these modes is shown to reproduce the velocity scale interaction phenomenon observed experimentally, as well as the corresponding strong gradient in the scalar field. This work was made possible through the support of United States Air Force Grants FA9550-16-1-0361 and FA9550-16-1-0232 as well as a National Defense Science and Engineering Graduate (NDSEG) fellowship.

Early vestibular processing does not discriminate active from passive self-motion if there is a discrepancy between predicted and actual proprioceptive feedback

PubMed Central

Brooks, Jessica X.

2014-01-01

Most of our sensory experiences are gained by active exploration of the world. While the ability to distinguish sensory inputs resulting of our own actions (termed reafference) from those produced externally (termed exafference) is well established, the neural mechanisms underlying this distinction are not fully understood. We have previously proposed that vestibular signals arising from self-generated movements are inhibited by a mechanism that compares the internal prediction of the proprioceptive consequences of self-motion to the actual feedback. Here we directly tested this proposal by recording from single neurons in monkey during vestibular stimulation that was externally produced and/or self-generated. We show for the first time that vestibular reafference is equivalently canceled for self-generated sensory stimulation produced by activation of the neck musculature (head-on-body motion), or axial musculature (combined head and body motion), when there is no discrepancy between the predicted and actual proprioceptive consequences of self-motion. However, if a discrepancy does exist, central vestibular neurons no longer preferentially encode vestibular exafference. Specifically, when simultaneous active and passive motion resulted in activation of the same muscle proprioceptors, neurons robustly encoded the total vestibular input (i.e., responses to vestibular reafference and exafference were equally strong), rather than exafference alone. Taken together, our results show that the cancellation of vestibular reafference in early vestibular processing requires an explicit match between expected and actual proprioceptive feedback. We propose that this vital neuronal computation, necessary for both accurate sensory perception and motor control, has important implications for a variety of sensory systems that suppress self-generated signals. PMID:24671531

Re-examining overlap between tactile and visual motion responses within hMT+ and STS

PubMed Central

Jiang, Fang; Beauchamp, Michael S.; Fine, Ione

2015-01-01

Here we examine overlap between tactile and visual motion BOLD responses within the human MT+ complex. Although several studies have reported tactile responses overlapping with hMT+, many used group average analyses, leaving it unclear whether these responses were restricted to sub-regions of hMT+. Moreover, previous studies either employed a tactile task or passive stimulation, leaving it unclear whether or not tactile responses in hMT+ are simply the consequence of visual imagery. Here we carried out a replication of one of the classic papers finding tactile responses in hMT+ (Hagen et al. 2002). We mapped MT and MST in individual subjects using visual field localizers. We then examined responses to tactile motion on the arm, either presented passively or in the presence of a visual task performed at fixation designed to minimize visualization of the concurrent tactile stimulation. To our surprise, without a visual task, we found only weak tactile motion responses in MT (6% of voxels showing tactile responses) and MST (2% of voxels). With an unrelated visual task designed to withdraw attention from the tactile modality, responses in MST reduced to almost nothing (<1% regions). Consistent with previous results, we did observe tactile responses in STS regions superior and anterior to hMT+. Despite the lack of individual overlap, group averaged responses produced strong spurious overlap between tactile and visual motion responses within hMT+ that resembled those observed in previous studies. The weak nature of tactile responses in hMT+ (and their abolition by withdrawal of attention) suggests that hMT+ may not serve as a supramodal motion processing module. PMID:26123373

The American Society of Shoulder and Elbow Therapists' consensus statement on rehabilitation following arthroscopic rotator cuff repair.

PubMed

Thigpen, Charles A; Shaffer, Michael A; Gaunt, Bryce W; Leggin, Brian G; Williams, Gerald R; Wilcox, Reg B

2016-04-01

This is a consensus statement on rehabilitation developed by the American Society of Shoulder and Elbow Therapists. The purpose of this statement is to aid clinical decision making during the rehabilitation of patients after arthroscopic rotator cuff repair. The overarching philosophy of rehabilitation is centered on the principle of the gradual application of controlled stresses to the healing rotator cuff repair with consideration of rotator cuff tear size, tissue quality, and patient variables. This statement describes a rehabilitation framework that includes a 2-week period of strict immobilization and a staged introduction of protected, passive range of motion during weeks 2-6 postoperatively, followed by restoration of active range of motion, and then progressive strengthening beginning at postoperative week 12. When appropriate, rehabilitation continues with a functional progression for return to athletic or demanding work activities. This document represents the first consensus rehabilitation statement developed by a multidisciplinary society of international rehabilitation professionals specifically for the postoperative care of patients after arthroscopic rotator cuff repair. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

The hydrodynamic basis of the vacuum cleaner effect in continuous-flow PCNL instruments: an empiric approach and mathematical model.

PubMed

Mager, R; Balzereit, C; Gust, K; Hüsch, T; Herrmann, T; Nagele, U; Haferkamp, A; Schilling, D

2016-05-01

Passive removal of stone fragments in the irrigation stream is one of the characteristics in continuous-flow PCNL instruments. So far the physical principle of this so-called vacuum cleaner effect has not been fully understood yet. The aim of the study was to empirically prove the existence of the vacuum cleaner effect and to develop a physical hypothesis and generate a mathematical model for this phenomenon. In an empiric approach, common low-pressure PCNL instruments and conventional PCNL sheaths were tested using an in vitro model. Flow characteristics were visualized by coloring of irrigation fluid. Influence of irrigation pressure, sheath diameter, sheath design, nephroscope design and position of the nephroscope was assessed. Experiments were digitally recorded for further slow-motion analysis to deduce a physical model. In each tested nephroscope design, we could observe the vacuum cleaner effect. Increase in irrigation pressure and reduction in cross section of sheath sustained the effect. Slow-motion analysis of colored flow revealed a synergism of two effects causing suction and transportation of the stone. For the first time, our model showed a flow reversal in the sheath as an integral part of the origin of the stone transportation during vacuum cleaner effect. The application of Bernoulli's equation provided the explanation of these effects and confirmed our experimental results. We widen the understanding of PCNL with a conclusive physical model, which explains fluid mechanics of the vacuum cleaner effect.

The Efficacy of Transverse Fixation and Early Exercise in the Treatment of Fourth Metacarpal Bone Fractures

PubMed Central

Moon, Suk-Ho; Kim, Hak-Soo; Jung, Sung-No

2016-01-01

Background Several techniques have been designed to treat fifth metacarpal fractures reported to be effective. However, these methods cannot be easily applied to the fourth metacarpal due to its central anatomical position. In this study, we sought to analyze the functional outcomes of patients who underwent transverse pinning for a fourth metacarpal bone fracture. Methods A total of 21 patients were selected and their charts were retrospectively reviewed. After fracture reduction, two transverse Kirchner wires were first inserted from the fifth metacarpal to the third metacarpal transversely at the distal part of the fractured bone, and then another two wires were inserted at the proximal part of the fractured bone. The splint was removed approximately one week postoperatively and the Kirchner wires were removed four to five weeks postoperatively. Patients started active and passive exercise one week after the operation. Pain visual analog scores, total active and passive motion, and the active and passive range of motion of the metacarpophalangeal joint and grip strength were evaluated. Results Dorsal angulation improved from a preoperative value of 44.2° to a postoperative value of 5.9°. Six weeks after surgery, functional recovery parameters, such as range of motion and grip strength, had improved to 98% of the function of the normal side. No major complication was observed. Conclusions We suggest that the transverse pinning of fourth metacarpal bone fractures is an effective treatment option that is less invasive than other procedures, easy to perform, requires no secondary surgery, minimizes joint and soft tissue injury, and allows early mobilization. PMID:27019812

Ontogenetic Development of Vestibulo-Ocular Reflexes in Amphibians

PubMed Central

Branoner, Francisco; Chagnaud, Boris P.; Straka, Hans

2016-01-01

Vestibulo-ocular reflexes (VOR) ensure gaze stability during locomotion and passively induced head/body movements. In precocial vertebrates such as amphibians, vestibular reflexes are required very early at the onset of locomotor activity. While the formation of inner ears and the assembly of sensory-motor pathways is largely completed soon after hatching, angular and translational/tilt VOR display differential functional onsets and mature with different time courses. Otolith-derived eye movements appear immediately after hatching, whereas the appearance and progressive amelioration of semicircular canal-evoked eye movements is delayed and dependent on the acquisition of sufficiently large semicircular canal diameters. Moreover, semicircular canal functionality is also required to tune the initially omnidirectional otolith-derived VOR. The tuning is due to a reinforcement of those vestibulo-ocular connections that are co-activated by semicircular canal and otolith inputs during natural head/body motion. This suggests that molecular mechanisms initially guide the basic ontogenetic wiring, whereas semicircular canal-dependent activity is required to establish the spatio-temporal specificity of the reflex. While a robust VOR is activated during passive head/body movements, locomotor efference copies provide the major source for compensatory eye movements during tail- and limb-based swimming of larval and adult frogs. The integration of active/passive motion-related signals for gaze stabilization occurs in central vestibular neurons that are arranged as segmentally iterated functional groups along rhombomere 1–8. However, at variance with the topographic maps of most other sensory systems, the sensory-motor transformation of motion-related signals occurs in segmentally specific neuronal groups defined by the extraocular motor output targets. PMID:27877114

Functional assessments of the knee joint biomechanics by using pendulum test in adults with Down syndrome

PubMed Central

Casabona, Antonino; Valle, Maria Stella; Pisasale, Mariangela; Pantò, Maria Rosita

2012-01-01

In this study, we assessed kinematics and viscoelastic features of knee joint in adults with Down syndrome (DS) by means of the Wartenberg pendulum test. This test allows the measuring of the kinematics of the knee joint during passive pendular motion of leg under the influence of gravity. In addition, by a combination of kinematic and anthropometric data, pendulum test provides estimates of joint viscoelastic properties by computing damping and stiffness coefficients. To monitor the occurrences of muscle activation, the surface electromyogram (EMG) of muscle rectus femoris was recorded. The experimental protocol was performed in a group of 10 adults with DS compared with 10 control adults without DS. Joint motion amplitude, velocity, and acceleration of the leg during the first knee flexion significantly decreased in persons with DS with respect to those without DS. This behavior was associated with the activation of rectus femoris in subjects with DS that resulted in increasing of joint resistance shortly after the onset of the first leg flexion. The EMG bursts mostly occurred between 50 and 150 ms from the leg flexion onset. During the remaining cycles of pendular motion, persons with DS exhibited passive leg oscillations with low tonic EMG activity and reduced damping coefficient compared with control subjects. These results suggest that adults with DS might perform preprogrammed contractions to increase joint resistance and compensate for inherent joint instability occurring for quick and unpredictable perturbations. The reduction of damping coefficients observed during passive oscillations could be a predictor of muscle hypotonia. PMID:22995394

Water channel experiments of a novel fully-passive flapping-foil turbine

NASA Astrophysics Data System (ADS)

Boudreau, Matthieu; Dumas, Guy; Rahimpour, Mostafa; Oshkai, Peter

2016-11-01

Experiments have been conducted to assess the performances of a fully-passive flapping-foil hydrokinetic turbine for which the blade's motions are stemming from the interaction between the blade's elastic supports (springs and dampers) and the flow field. Previous numerical studies conducted by Peng & Zhu (2009) and Zhu (2012) have proved that a simplified version of such a turbine can extract a substantial amount of energy from the flow while offering the potential to greatly simplify the complex mechanical apparatus needed to constrain and link the blade's pitching and heaving motions in the case of the more classical flapping-foil turbine (e.g., Kinsey et al., 2011). Based on the promising numerical investigations of Veilleux (2014) and Veilleux & Dumas (2016), who proposed a more general version of this novel concept, a prototype has been built and tested in a water channel at a chord Reynolds number of 17,000. Periodic motions of large amplitudes have been observed leading to interesting energy harvesting efficiencies reaching 25% for some specific sets of structural parameters. The sensitivity of the turbine's dynamics to each of the seven structural parameters appearing in the equations of motion has been experimentally evaluated around a case close to the optimal one. Financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC) is gratefully acknowledged by the authors.

Determination of the Ephemeris Accuracy for AJISAI, LAGEOS and ETALON Satellites, Obtained with A Simplified Numerical Motion Model Using the ILRS Coordinates

NASA Astrophysics Data System (ADS)

Kara, I. V.

This paper describes a simplified numerical model of passive artificial Earth satellite (AES) motion. The model accuracy is determined using the International Laser Ranging Service (ILRS) highprecision coordinates. Those data are freely available on http://ilrs.gsfc.nasa.gov. The differential equations of the AES motion are solved by the Everhart numerical method of 17th and 19th orders with the integration step automatic correction. The comparison between the AES coordinates computed with the motion model and the ILRS coordinates enabled to determine the accuracy of the ephemerides obtained. As a result, the discrepancy of the computed Etalon-1 ephemerides from the ILRS data is about 10'' for a one-year ephemeris.

Motion Sickness Treatment Apparatus and Method

NASA Technical Reports Server (NTRS)

Reschke, Millard F. (Inventor); Somers, Jeffrey T. (Inventor); Ford, George A. (Inventor)

2005-01-01

Methods and apparatus are disclosed for treating motion sickness. In a preferred embodiment a method of the invention comprises operating eyewear having shutter lenses to open said shutter lenses at a selected operating frequency ranging from within about 3 Hz to about 50 Hz. The shutter lenses are opened for a short duration at the selected operating frequency wherein the duration is selected to prevent retinal slip. The shutter lenses may be operated at a relatively slow frequency of about 4 Hz when the user is in passive activity such as riding in a boat or car or in limited motion situations in a spacecraft. The shutter lenses may be operated at faster frequencies related to motion of the user's head when the user is active.

Outpatient rehabilitation care process factors and clinical outcomes among patients discharged home following unilateral total knee arthroplasty.

PubMed

Brennan, Gerard P; Fritz, Julie M; Houck, L T C Kevin M; Hunter, Stephen J

2015-05-01

Research examining care process variables and their relationship to clinical outcomes after total knee arthroplasty has focused primarily on inpatient variables. Care process factors related to outpatient rehabilitation have not been adequately examined. We conducted a retrospective review of 321 patients evaluating outpatient care process variables including use of continuous passive motion, home health physical therapy, number of days from inpatient discharge to beginning outpatient physical therapy, and aspects of outpatient physical therapy (number of visits, length of stay) as possible predictors of pain and disability outcomes of outpatient physical therapy. Only the number of days between inpatient discharge and outpatient physical therapy predicted better outcomes, suggesting that this may be a target for improving outcomes after total knee arthroplasty for patients discharged directly home. Copyright © 2014 Elsevier Inc. All rights reserved.

Unbinding Transition of Probes in Single-File Systems

NASA Astrophysics Data System (ADS)

Bénichou, Olivier; Démery, Vincent; Poncet, Alexis

2018-02-01

Single-file transport, arising in quasi-one-dimensional geometries where particles cannot pass each other, is characterized by the anomalous dynamics of a probe, notably its response to an external force. In these systems, the motion of several probes submitted to different external forces, although relevant to mixtures of charged and neutral or active and passive objects, remains unexplored. Here, we determine how several probes respond to external forces. We rely on a hydrodynamic description of the symmetric exclusion process to obtain exact analytical results at long times. We show that the probes can either move as a whole, or separate into two groups moving away from each other. In between the two regimes, they separate with a different dynamical exponent, as t1 /4. This unbinding transition also occurs in several continuous single-file systems and is expected to be observable.

HIP AND GLENOHUMERAL PASSIVE RANGE OF MOTION IN COLLEGIATE SOFTBALL PLAYERS

PubMed Central

Plummer, Hillary; Brambeck, Allison

2016-01-01

Background and Purpose Range of motion deficits at the hip and glenohumeral joint (GHJ) may contribute to the incidence of injury in softball players. With injury in softball players on the rise, softball related studies in the literature are important. The purpose of this study was to examine hip and GHJ passive range of motion (PROM) patterns in collegiate softball players. Hypothesis It was hypothesized that the position players would exhibit significantly different PROM patterns than pitchers. Additionally, position players would exhibit significantly different side-to-side differences in PROM for both the hip and GHJ compared to pitchers. Study Design Prospective cohort study. Methods Forty-nine collegiate softball players (19.63 ± 1.15 years; 170.88 ± 8.08 cm; 72.96 ± 19.41 kg) participated. Passive hip and GHJ internal (IR) and external rotation (ER) measures were assessed. Glenohumeral PROM was measured with the participants supine with the arm abducted to 90 °. The measurements were recorded when the scapula began to move or a firm capsular end-feel was achieved. The hip was positioned in 90 ° of flexion and passively rotated until a capsular end-feel was achieved. Total PROM was calculated by taking the sum of IR and ER for both the hip and GHJ. Results No significant side-to-side PROM differences were observed in pitchers, at the GHJ or hip joint. Position players throwing side hip IR was significantly greater than the non-throwing side hip (p = 0.002). The non-throwing side hip had significantly greater ER compared to the throwing side hip (p = 0.002). When examining side-to-side differences at the GHJ, IR was significantly greater in the non-throwing shoulder (p = 0.047). No significant differences in total range of motion of the hip and GHJ were observed. Conclusion In the current study, position players displayed side-to-side differences in hip and GHJ IR PROM while no statistically significant differences were observed in the softball pitchers. The findings of the current study add to the body of literature related to PROM in throwing athletes, additionally these are the first hip IR and ER PROM data presented in softball players. Level of Evidence Level 3 PMID:27757286

Modeling, design, and testing of a proof-of-concept prototype damper with friction and eddy current damping effects

NASA Astrophysics Data System (ADS)

Amjadian, Mohsen; Agrawal, Anil K.

2018-01-01

Friction is considered as one of the most reliable mechanisms of energy dissipation that has been utilized extensively in passive damping devices to mitigate vibration of civil engineering structures subjected to extreme natural hazards such as earthquakes and windstorms. However, passive friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably. The authors have recently proposed the theoretical concept of a new type of damping device termed as "Passive Electromagnetic Eddy Current Friction Damper" (PEMECFD) in which an eddy current damping mechanism was utilized not only to decrease the undesirable effects of stick-slip motion, but also to increase the energy dissipation capacity of the damping device as a whole. That study was focused on demonstration of the theoretical performance of the proposed damping device through numerical simulations. This paper further investigates the influence of eddy current damping on energy dissipation due to friction through modeling, design, and testing of a proof-of-concept prototype damper. The design of this damper has been improved over the design in the previous study. The normal force in this damper is produced by the repulsive magnetic force between two cuboidal permanent magnets (PMs) magnetized in the direction normal to the direction of the motion. The eddy current damping force is generated because of the motion of the two PMs and two additional PMs relative to a copper plate in their vicinity. The dynamic models for the force-displacement relationship of the prototype damper are based on LuGre friction model, electromagnetic theory, and inertial effects of the prototype damper. The parameters of the dynamic models have been identified through a series of characterization tests on the prototype damper under harmonic excitations of different frequencies in the laboratory. Finally, the identified dynamic models have been validated by subjecting the prototype damper to two different random excitations. The results indicate that the proposed dynamic models are capable of representing force-displacement behavior of the new type of passive damping device for a wide range of operating conditions.

Effects of Ultrasound-guided intra-articular ketorolac injection with capsular distension.

PubMed

Ahn, Jae Ki; Kim, Jongwoo; Lee, Sang Jae; Park, Yongbum; Bae, Byung; Lee, Woo

2015-01-01

Frozen shoulder is a painful condition with gradual onset and loss of range of motion in the glenohumeral joint. To investigate the efficacy of ultrasound(US)-guided intra-articular (IA) ketorolac injection with capsular distension compared with steroid injection alone in patients with frozen shoulder by assessing pain relief, functional improvements, and range of motion at 1,3 and 6 months after the last injections. Between January 2009 and December 2012, 121 patient were treated with US-guided IA steroid injection or IA ketorolac injection with capsular distension for frozen shoulder. Patients (n= 57) of US-guided IA steroid injection group were administered with a mixture of 0.5% lidocaine (4 ml) plus triamcinolone (40 mg/ml; 1 ml) and patients (n= 64) of US-guided IA ketorolac injection with capsular distension group were administered by using 0.5% lidocaine (19 mL) plus ketorolac (30 mg/ml; 1 mL) for capsular distension. Outcome measurement was assessed by Shoulder Pain and Disability Index (SPADI), Verbal Numeric pain Scale (VNS) and passive range of motion (ROM) before injections and at 1, 3 and 6 months after the last injections. We regarded the outcomes as a success if patients obtained significant pain relief (as measured by > 50% improvement in the VNS score and 20 point improvement in the SPASI) at 1, 3 and 6 months after the last injections. SPADI, VNS and passive ROM were improved 1, 3 and 6 months after the last injections in both groups. The statistical differences were not observed in SPADI, VNS between groups (p< 0.05). Successful treatment rate were not significantly different between the groups as well as in 1, 3 and 6 month outcomes. However, greater improvement was found in a matter of range of motion in patients receiving IA ketorolac injection with capsular distension than participants receiving US-guided IA steroid injection alone. Significant differences in improvement at 3 and 6 months were observed for shoulder passive abduction and external rotation (p< 0.05). IA ketorolac injection with capsular distension was shown to be a treatment method as effective as the steroid injection alone in pain relief and functional improvement in patient with frozen shoulder and more improvement in passive abduction and external rotation than steroid injection alone at 3 and 6 months.

Measurement of Shoulder Range of Motion in Patients with Adhesive Capsulitis Using a Kinect

PubMed Central

Chung, Sun Gun; Kim, Hee Chan; Kwak, Youngbin; Park, Hee-won; Kim, Keewon

2015-01-01

Range of motion (ROM) measurements are essential for the evaluation for and diagnosis of adhesive capsulitis of the shoulder (AC). However, taking these measurements using a goniometer is inconvenient and sometimes unreliable. The Kinect (Microsoft, Seattle, WA, USA) is gaining attention as a new motion detecting device that is nonintrusive and easy to implement. This study aimed to apply Kinect to measure shoulder ROM in AC; we evaluated its validity by calculating the agreement of the measurements obtained using Kinect with those obtained using goniometer and assessed its utility for the diagnosis of AC. Both shoulders of 15 healthy volunteers and affected shoulders of 12 patients with AC were included in the study. The passive and active ROM of each were measured with a goniometer for flexion, abduction, and external rotation. Their active shoulder motions for each direction were again captured using Kinect and the ROM values were calculated. The agreement between the two measurements was tested with the intraclass correlation coefficient (ICC). Diagnostic performance using the Kinect ROM was evaluated with Cohen’s kappa value. The cutoff values of the limited ROM were determined in the following ways: the same as passive ROM values, reflecting the mean difference, and based on receiver operating characteristic curves. The ICC for flexion/abduction/external rotation between goniometric passive ROM and the Kinect ROM were 0.906/0.942/0.911, while those between active ROMs and the Kinect ROMs were 0.864/0.932/0.925. Cohen’s kappa values were 0.88, 0.88, and 1.0 with the cutoff values in the order above. Measurements of the shoulder ROM using Kinect show excellent agreement with those taken using a goniometer. These results indicate that the Kinect can be used to measure shoulder ROM and to diagnose AC as an alternative to goniometer. PMID:26107943

Linking Observations of Dynamic Topography from Oceanic and Continental Realms around Australia

NASA Astrophysics Data System (ADS)

Czarnota, K.; Hoggard, M. J.; White, N.; Winterbourne, J.

2012-04-01

In the last decade, there has been growing interest in predicting the spatial and temporal evolution of dynamic topography (i.e. the surface manifestation of mantle convection). By directly measuring Neogene and Quaternary dynamic topography around Australia's passive margins we assess the veracity of these predictions and the interplay between mantle convection and plate motion. We mapped the present dynamic topography by carefully measuring residual topography of oceanic lithosphere adjacent to passive margins. This map provides a reference with respect to which the relative record of vertical motions, preserved within the stratigraphic architecture of the margins, can be interpreted. We carefully constrained the temporal record of vertical motions along Australia's Northwest Shelf by backstripping Neogene carbonate clinoform rollover trajectories in order to minimise paleobathymetric errors. Elsewhere, we compile temporal constraints from published literature. Three principal insights emerge from our analysis. First, the present-day drawn-down residual topography of Australia, cannot be approximated by a regional tilt down towards the northeast, as previously hypothesised. The south-western and south-eastern corners of Australia are at negligible to slightly positive residual topography which slopes down towards Australia's northern margin and the Great Australian Bight. Secondly, the record of passive margin subsidence suggests drawdown across northern Australia commenced synchronously at 8±2 Ma. The amplitude of this synchronous drawdown corresponds to the amplitude of oceanic residual topography, indicating northern Australia was at an unperturbed dynamic elevation until drawdown commenced. The synchronicity of this subsidence suggests that the Australian plate has not been affected by a southward propagating wave of drawdown, despite Australia's rapid northward motion towards the subduction realm in south-east Asia. In contrast, it appears the mantle anomaly responsible for this drawdown is a relatively young, long-wavelength feature. Thirdly, there is an apparent mismatch between the current drawdown of oceanic lithosphere observed along Australia's southern margin and the onshore record of Cenozoic uplift. This disparity we attribute to the region undergoing recent uplift from a position of dynamic drawdown.

Design and analysis of a shock absorber with variable moment of inertia for passive vehicle suspensions

NASA Astrophysics Data System (ADS)

Xu, Tongyi; Liang, Ming; Li, Chuan; Yang, Shuai

2015-10-01

A two-terminal mass (TTM) based vibration absorber with variable moment of inertia (VMI) for passive vehicle suspension is proposed. The VMI of the system is achieved by the motion of sliders embedded in a hydraulic driven flywheel. The moment of inertia increases in reaction to strong vertical vehicle oscillations and decreases for weak vertical oscillations. The hydraulic mechanism of the system converts the relative linear motion between the two terminals of the suspension into rotating motion of the flywheel. In the case of stronger vehicle vertical oscillation, the sliders inside the flywheel move away from the center of the flywheel because of the centrifugal force, hence yielding higher moment of inertia. The opposite is true in the case of weaker vehicle oscillation. As such, the moment of inertia adjusts itself adaptively in response to the road conditions. The performance of the proposed TTM-VMI absorber has been analyzed via dynamics modeling and simulation and further examined by experiments. In comparison to its counterpart with constant moment of inertia, the proposed VMI system offers faster response, better road handling and safety, improved ride comfort, and reduced suspension deflection except in the case of sinusoidal excitations.

Enhancement of vortex induced forces and motion through surface roughness control

DOEpatents

Bernitsas, Michael M [Saline, MI; Raghavan, Kamaldev [Houston, TX

2011-11-01

Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to increase Vortex Induced Forces and Motion. Enhancement is needed in such applications as harnessing of clean and renewable energy from ocean/river currents using the ocean energy converter VIVACE (Vortex Induced Vibration for Aquatic Clean Energy).

Periodic motion planning and control for underactuated mechanical systems

NASA Astrophysics Data System (ADS)

Wang, Zeguo; Freidovich, Leonid B.; Zhang, Honghua

2018-06-01

We consider the problem of periodic motion planning and of designing stabilising feedback control laws for such motions in underactuated mechanical systems. A novel periodic motion planning method is proposed. Each state is parametrised by a truncated Fourier series. Then we use numerical optimisation to search for the parameters of the trigonometric polynomial exploiting the measure of discrepancy in satisfying the passive dynamics equations as a performance index. Thus an almost feasible periodic motion is found. Then a linear controller is designed and stability analysis is given to verify that solutions of the closed-loop system stay inside a tube around the planned approximately feasible periodic trajectory. Experimental results for a double rotary pendulum are shown, while numerical simulations are given for models of a spacecraft with liquid sloshing and of a chain of mass spring system.

Hydrodynamic effects on phase transition in active matter

NASA Astrophysics Data System (ADS)

Gidituri, Harinadha; Akella, V. S.; Panchagnula, Mahesh; Vedantam, Srikanth; Multiphase flow physics lab Team

2017-11-01

Organized motion of active (self-propelled) objects are ubiquitous in nature. The objective of this study to investigate the effect of hydrodynamics on the coherent structures in active and passive particle mixtures. We use a mesoscopic method Dissipative Particle Dynamics (DPD). The system shows three different states viz. meso-turbulent (disordered state), polar flock and vortical (ordered state) for different values of activity and volume fraction of active particles. From our numerical simulations we construct a phase diagram between activity co-efficient, volume fraction and viscosity of the passive fluid. Transition from vortical to polar is triggered by increasing the viscosity of passive fluid which causes strong short-range hydrodynamic interactions. However, as the viscosity of the fluid decreases, both vortical and meso-turbulent states transition to polar flock phase. We also calculated the diffusion co-efficients via mean square displacement (MSD) for passive and active particles. We observe ballistic and diffusive regimes in the present system.

Passive motion reduces vestibular balance and perceptual responses

PubMed Central

Fitzpatrick, Richard C; Watson, Shaun R D

2015-01-01

With the hypothesis that vestibular sensitivity is regulated to deal with a range of environmental motion conditions, we explored the effects of passive whole-body motion on vestibular perceptual and balance responses. In 10 subjects, vestibular responses were measured before and after a period of imposed passive motion. Vestibulospinal balance reflexes during standing evoked by galvanic vestibular stimulation (GVS) were measured as shear reaction forces. Perceptual tests measured thresholds for detecting angular motion, perceptions of suprathreshold rotation and perceptions of GVS-evoked illusory rotation. The imposed conditioning motion was 10 min of stochastic yaw rotation (0.5–2.5 Hz ≤ 300 deg s−2) with subjects seated. This conditioning markedly reduced reflexive and perceptual responses. The medium latency galvanic reflex (300–350 ms) was halved in amplitude (48%; P = 0.011) but the short latency response was unaffected. Thresholds for detecting imposed rotation more than doubled (248%; P < 0.001) and remained elevated after 30 min. Over-estimation of whole-body rotation (30–180 deg every 5 s) before conditioning was significantly reduced (41.1 to 21.5%; P = 0.033). Conditioning reduced illusory vestibular sensations of rotation evoked by GVS (mean 113 deg for 10 s at 1 mA) by 44% (P < 0.01) and the effect persisted for at least 1 h (24% reduction; P < 0.05). We conclude that a system of vestibular sensory autoregulation exists and that this probably involves central and peripheral mechanisms, possibly through vestibular efferent regulation. We propose that failure of these regulatory mechanisms at different levels could lead to disorders of movement perception and balance control during standing. Key points Human activity exposes the vestibular organs to a wide dynamic range of motion. We aimed to discover whether the CNS regulates sensitivity to vestibular afference during exposure to ambient motion. Balance and perceptual responses to vestibular stimulation were measured before and after a 10 min period of imposed, moderate intensity, stochastic whole-body rotation. After this conditioning, vestibular balance reflexes evoked by galvanic vestibular stimulation were halved in amplitude. Conditioning doubled the thresholds for perceiving small rotations, and reduced perceptions of the amplitude of real rotations, and illusory rotation evoked by galvanic stimulation. We conclude that the CNS auto-regulates sensitivity to vestibular sensory afference and that this probably involves central and peripheral mechanisms, as might arise from vestibular efferent regulation. Failure of these regulatory mechanisms at different levels could lead to disorders of movement perception and balance control during standing. PMID:25809702

Zooplankton can actively adjust their motility to turbulent flow

PubMed Central

Michalec, François-Gaël; Fouxon, Itzhak

2017-01-01

Calanoid copepods are among the most abundant metazoans in the ocean and constitute a vital trophic link within marine food webs. They possess relatively narrow swimming capabilities, yet are capable of significant self-locomotion under strong hydrodynamic conditions. Here we provide evidence for an active adaptation that allows these small organisms to adjust their motility in response to background flow. We track simultaneously and in three dimensions the motion of flow tracers and planktonic copepods swimming freely at several intensities of quasi-homogeneous, isotropic turbulence. We show that copepods synchronize the frequency of their relocation jumps with the frequency of small-scale turbulence by performing frequent relocation jumps of low amplitude that seem unrelated to localized hydrodynamic signals. We develop a model of plankton motion in turbulence that shows excellent quantitative agreement with our measurements when turbulence is significant. We find that, compared with passive tracers, active motion enhances the diffusion of organisms at low turbulence intensity whereas it dampens diffusion at higher turbulence levels. The existence of frequent jumps in a motion that is otherwise dominated by turbulent transport allows for the possibility of active locomotion and hence to transition from being passively advected to being capable of controlling diffusion. This behavioral response provides zooplankton with the capability to retain the benefits of self-locomotion despite turbulence advection and may help these organisms to actively control their distribution in dynamic environments. Our study reveals an active adaptation that carries strong fitness advantages and provides a realistic model of plankton motion in turbulence. PMID:29229858

Visual Acuity Using Head-fixed Displays During Passive Self and Surround Motion

NASA Technical Reports Server (NTRS)

Wood, Scott J.; Black, F. Owen; Stallings, Valerie; Peters, Brian

2007-01-01

The ability to read head-fixed displays on various motion platforms requires the suppression of vestibulo-ocular reflexes. This study examined dynamic visual acuity while viewing a head-fixed display during different self and surround rotation conditions. Twelve healthy subjects were asked to report the orientation of Landolt C optotypes presented on a micro-display fixed to a rotating chair at 50 cm distance. Acuity thresholds were determined by the lowest size at which the subjects correctly identified 3 of 5 optotype orientations at peak velocity. Visual acuity was compared across four different conditions, each tested at 0.05 and 0.4 Hz (peak amplitude of 57 deg/s). The four conditions included: subject rotated in semi-darkness (i.e., limited to background illumination of the display), subject stationary while visual scene rotated, subject rotated around a stationary visual background, and both subject and visual scene rotated together. Visual acuity performance was greatest when the subject rotated around a stationary visual background; i.e., when both vestibular and visual inputs provided concordant information about the motion. Visual acuity performance was most reduced when the subject and visual scene rotated together; i.e., when the visual scene provided discordant information about the motion. Ranges of 4-5 logMAR step sizes across the conditions indicated the acuity task was sufficient to discriminate visual performance levels. The background visual scene can influence the ability to read head-fixed displays during passive motion disturbances. Dynamic visual acuity using head-fixed displays can provide an operationally relevant screening tool for visual performance during exposure to novel acceleration environments.

3D Tracking of Diatom Motion in Turbulent Flow

NASA Astrophysics Data System (ADS)

Variano, E. A.; Brandt, L.; Sardina, G.; Ardekani, M.; Pujara, N.; Ayers, S.; Du Clos, K.; Karp-Boss, L.; Jumars, P. A.

2016-02-01

We present laboratory measurements of single-celled and chain forming diatom motion in a stirred turbulence tank. The overarching goal is to explore whether diatoms track flow with fidelity (passive tracers) or whether interactions with cell density and shape result in biased trajectories that alter settling velocities. Diatom trajectories are recorded in 3D using a stereoscopic, calibrated tracking tool. Turbulence is created in a novel stirred tank, designed to create motions that match those found in the ocean surface mixed layer at scales less than 10 cm. The data are analyzed for evidence of enhanced particle clustering, an indicator of turbulently altered settling rates

Real-Time Observation of Internal Motion within Ultrafast Dissipative Optical Soliton Molecules

NASA Astrophysics Data System (ADS)

Krupa, Katarzyna; Nithyanandan, K.; Andral, Ugo; Tchofo-Dinda, Patrice; Grelu, Philippe

2017-06-01

Real-time access to the internal ultrafast dynamics of complex dissipative optical systems opens new explorations of pulse-pulse interactions and dynamic patterns. We present the first direct experimental evidence of the internal motion of a dissipative optical soliton molecule generated in a passively mode-locked erbium-doped fiber laser. We map the internal motion of a soliton pair molecule by using a dispersive Fourier-transform imaging technique, revealing different categories of internal pulsations, including vibrationlike and phase drifting dynamics. Our experiments agree well with numerical predictions and bring insights to the analogy between self-organized states of lights and states of the matter.

Reference frame access under the effects of great earthquakes: a least squares collocation approach for non-secular post-seismic evolution

NASA Astrophysics Data System (ADS)

Gómez, D. D.; Piñón, D. A.; Smalley, R.; Bevis, M.; Cimbaro, S. R.; Lenzano, L. E.; Barón, J.

2016-03-01

The 2010, (Mw 8.8) Maule, Chile, earthquake produced large co-seismic displacements and non-secular, post-seismic deformation, within latitudes 28°S-40°S extending from the Pacific to the Atlantic oceans. Although these effects are easily resolvable by fitting geodetic extended trajectory models (ETM) to continuous GPS (CGPS) time series, the co- and post-seismic deformation cannot be determined at locations without CGPS (e.g., on passive geodetic benchmarks). To estimate the trajectories of passive geodetic benchmarks, we used CGPS time series to fit an ETM that includes the secular South American plate motion and plate boundary deformation, the co-seismic discontinuity, and the non-secular, logarithmic post-seismic transient produced by the earthquake in the Posiciones Geodésicas Argentinas 2007 (POSGAR07) reference frame (RF). We then used least squares collocation (LSC) to model both the background secular inter-seismic and the non-secular post-seismic components of the ETM at the locations without CGPS. We tested the LSC modeled trajectories using campaign and CGPS data that was not used to generate the model and found standard deviations (95 % confidence level) for position estimates for the north and east components of 3.8 and 5.5 mm, respectively, indicating that the model predicts the post-seismic deformation field very well. Finally, we added the co-seismic displacement field, estimated using an elastic finite element model. The final, trajectory model allows accessing the POSGAR07 RF using post-Maule earthquake coordinates within 5 cm for ˜ 91 % of the passive test benchmarks.

A painless and constraint-free method to estimate viscoelastic passive dynamics of limbs' joints to support diagnosis of neuromuscular diseases.

PubMed

Venture, Gentiane; Nakamura, Yoshihiko; Yamane, Katsu; Hirashima, Masaya

2007-01-01

Though seldom identified, the human joints dynamics is important in the fields of medical robotics and medical research. We present a general solution to estimate in-vivo and simultaneously the passive dynamics of the human limbs' joints. It is based on the use of the multi-body description of the human body and its kinematics and dynamics computations. The linear passive joint dynamics of the shoulders and the elbows: stiffness, viscosity and friction, is estimated simultaneously using the linear least squares method. Acquisition of movements is achieved with an optical motion capture studio on one examinee during the clinical diagnosis of neuromuscular diseases. Experimental results are given and discussed.

Variation in detection among passive infrared triggered-cameras used in wildlife research

USGS Publications Warehouse

Damm, Philip E.; Grand, James B.; Barnett, Steven W.

2010-01-01

Precise and accurate estimates of demographics such as age structure, productivity, and density are necessary in determining habitat and harvest management strategies for wildlife populations. Surveys using automated cameras are becoming an increasingly popular tool for estimating these parameters. However, most camera studies fail to incorporate detection probabilities, leading to parameter underestimation. The objective of this study was to determine the sources of heterogeneity in detection for trail cameras that incorporate a passive infrared (PIR) triggering system sensitive to heat and motion. Images were collected at four baited sites within the Conecuh National Forest, Alabama, using three cameras at each site operating continuously over the same seven-day period. Detection was estimated for four groups of animals based on taxonomic group and body size. Our hypotheses of detection considered variation among bait sites and cameras. The best model (w=0.99) estimated different rates of detection for each camera in addition to different detection rates for four animal groupings. Factors that explain this variability might include poor manufacturing tolerances, variation in PIR sensitivity, animal behavior, and species-specific infrared radiation. Population surveys using trail cameras with PIR systems must incorporate detection rates for individual cameras. Incorporating time-lapse triggering systems into survey designs should eliminate issues associated with PIR systems.

Inertial navigation sensor integrated obstacle detection system

NASA Technical Reports Server (NTRS)

Bhanu, Bir (Inventor); Roberts, Barry A. (Inventor)

1992-01-01

A system that incorporates inertial sensor information into optical flow computations to detect obstacles and to provide alternative navigational paths free from obstacles. The system is a maximally passive obstacle detection system that makes selective use of an active sensor. The active detection typically utilizes a laser. Passive sensor suite includes binocular stereo, motion stereo and variable fields-of-view. Optical flow computations involve extraction, derotation and matching of interest points from sequential frames of imagery, for range interpolation of the sensed scene, which in turn provides obstacle information for purposes of safe navigation.

Evaluation of the TOPSAR performance by using passive and active calibrators

NASA Technical Reports Server (NTRS)

Alberti, G.; Moccia, A.; Ponte, S.; Vetrella, S.

1992-01-01

The preliminary analysis of the C-band cross-track interferometric data (XTI) acquired during the MAC Europe 1991 campaign over the Matera test site, in Southern Italy is presented. Twenty three passive calibrators (Corner Reflector, CR) and 3 active calibrators (Active Radar Calibrator, ARC) were deployed over an area characterized by homogeneous background. Contemporaneously to the flight, a ground truth data collection campaign was carried out. The research activity was focused on the development of motion compensation algorithms, in order to improve the height measurement accuracy of the TOPSAR system.

Feedback-controlled and programmed stretching of the ankle plantarflexors and dorsiflexors in stroke: effects of a 4-week intervention program.

PubMed

Selles, Ruud W; Li, Xiaoyan; Lin, Fang; Chung, Sun G; Roth, Elliot J; Zhang, Li-Qun

2005-12-01

To investigate the effect of repeated feedback-controlled and programmed "intelligent" stretching of the ankle plantar- and dorsiflexors to treat subjects with ankle spasticity and/or contracture in stroke. Noncontrolled trial. Institutional research center. Subjects with spasticity and/or contracture after stroke. Stretching of the plantar- and dorsiflexors of the ankle 3 times a week for 45 minutes during a 4-week period by using a feedback-controlled and programmed stretching device. Passive and active range of motion (ROM), muscle strength, joint stiffness, joint viscous damping, reflex excitability, comfortable walking speed, and subjective experiences of the subjects. Significant improvements were found in the passive ROM, maximum voluntary contraction, ankle stiffness, and comfortable walking speed. The visual analog scales indicated very positive subjective evaluation in terms of the comfort of stretching and the effect on their involved ankle. Repeated feedback-controlled or intelligent stretching had a positive influence on the joint properties of the ankle with spasticity and/or contracture after stroke. The stretching device may be an effective and safe alternative to manual passive motion treatment by a therapist and has potential to be used to repeatedly and regularly stretch the ankle of subjects with spasticity and/or contracture without daily involvement of clinicians or physical therapists.

Active and passive transport of cargo in a corrugated channel: A lattice model study

NASA Astrophysics Data System (ADS)

Dey, Supravat; Ching, Kevin; Das, Moumita

2018-04-01

Inside cells, cargos such as vesicles and organelles are transported by molecular motors to their correct locations via active motion on cytoskeletal tracks and passive, Brownian diffusion. During the transportation of cargos, motor-cargo complexes (MCCs) navigate the confining and crowded environment of the cytoskeletal network and other macromolecules. Motivated by this, we study a minimal two-state model of motor-driven cargo transport in confinement and predict transport properties that can be tested in experiments. We assume that the motion of the MCC is directly affected by the entropic barrier due to confinement if it is in the passive, unbound state but not in the active, bound state where it moves with a constant bound velocity. We construct a lattice model based on a Fokker Planck description of the two-state system, study it using a kinetic Monte Carlo method and compare our numerical results with analytical expressions for a mean field limit. We find that the effect of confinement strongly depends on the bound velocity and the binding kinetics of the MCC. Confinement effectively reduces the effective diffusivity and average velocity, except when it results in an enhanced average binding rate and thereby leads to a larger average velocity than when unconfined.

Sciatic nerve stiffness is not changed immediately after a slump neurodynamics technique.

PubMed

Neto, Tiago; Freitas, Sandro R; Andrade, Ricardo J; Gomes, João; Vaz, João; Mendes, Bruno; Firmino, Telmo; Nordez, Antoine; Oliveira, Raúl

2017-01-01

Neurodynamics techniques aim to assess and improve neural mechanosensitivity. However, there is no in vivo evidence regarding the mechanical effects of these techniques in the nerve stiffness. This study examined the immediate effects of a slump neurodynamics technique in the sciatic nerve shear wave velocity (SWV. i.e. an index of stiffness) using ultrasound-based elastography. Fourteen healthy participants were included in this experiment. Sciatic SWV and ankle passive torque were measured during a passive ankle dorsiflexion motion (2°/s), before and immediately after 3 minutes of slump neurodynamics technique, randomly applied to one lower limb. The contralateral limb served as control. The slump intervention did not change the sciatic SWV (P=0.78), nor the dorsiflexion passive torque (P=0.14), throughout the ankle dorsiflexion motion. Excellent values of intra-rater repeatability (ICC=0.88, 0.68-0.96), and low values of standard error of measurement (0.59 m/s, 0.35-1.15m/s), were observed for the SWV measurements. The sciatic nerve stiffness of healthy participants did not change immediately after a slump neurodynamics technique, suggesting a compliance of the neural tissue to tensile loads. However, these results ought to be confirmed using other neurodynamics techniques and in other populations (e.g. peripheral neuropathies). III.

Fault-tolerant feature-based estimation of space debris rotational motion during active removal missions

NASA Astrophysics Data System (ADS)

Biondi, Gabriele; Mauro, Stefano; Pastorelli, Stefano; Sorli, Massimo

2018-05-01

One of the key functionalities required by an Active Debris Removal mission is the assessment of the target kinematics and inertial properties. Passive sensors, such as stereo cameras, are often included in the onboard instrumentation of a chaser spacecraft for capturing sequential photographs and for tracking features of the target surface. A plenty of methods, based on Kalman filtering, are available for the estimation of the target's state from feature positions; however, to guarantee the filter convergence, they typically require continuity of measurements and the capability of tracking a fixed set of pre-defined features of the object. These requirements clash with the actual tracking conditions: failures in feature detection often occur and the assumption of having some a-priori knowledge about the shape of the target could be restrictive in certain cases. The aim of the presented work is to propose a fault-tolerant alternative method for estimating the angular velocity and the relative magnitudes of the principal moments of inertia of the target. Raw data regarding the positions of the tracked features are processed to evaluate corrupted values of a 3-dimentional parameter which entirely describes the finite screw motion of the debris and which primarily is invariant on the particular set of considered features of the object. Missing values of the parameter are completely restored exploiting the typical periodicity of the rotational motion of an uncontrolled satellite: compressed sensing techniques, typically adopted for recovering images or for prognostic applications, are herein used in a completely original fashion for retrieving a kinematic signal that appears sparse in the frequency domain. Due to its invariance about the features, no assumptions are needed about the target's shape and continuity of the tracking. The obtained signal is useful for the indirect evaluation of an attitude signal that feeds an unscented Kalman filter for the estimation of the global rotational state of the target. The results of the computer simulations showed a good robustness of the method and its potential applicability for general motion conditions of the target.

Rehabilitation after Rotator Cuff Repair.

PubMed

Nikolaidou, Ourania; Migkou, Stefania; Karampalis, Christos

2017-01-01

Rotator cuff tears are a very common condition that is often incapacitating. Whether non-surgical or surgical, successful management of rotator cuff disease is dependent on appropriate rehabilitation. If conservative management is insufficient, surgical repair is often indicated. Postsurgical outcomes for patients having had rotator cuff repair can be quite good. A successful outcome is much dependent on surgical technique as it is on rehabilitation. Numerous rehabilitation protocols for the management of rotator cuff disease are based primarily on clinical experience and expert opinion. This article describes the different rehabilitation protocols that aim to protect the repair in the immediate postoperative period, minimize postoperative stiffness and muscle atrophy. A review of currently available literature on rehabilitation after arthroscopic rotator cuff tear repair was performed to illustrate the available evidence behind various postoperative treatment modalities. There were no statistically significant differences between a conservative and an accelerated rehabilitation protocol . Early passive range of motion (ROM) following arthroscopic cuff repair is thought to decrease postoperative stiffness and improve functionality. However, early aggressive rehabilitation may compromise repair integrity. The currently available literature did not identify any significant differences in functional outcomes and relative risks of re-tears between delayed and early motion in patients undergoing arthroscopic rotator cuff repairs. A gentle rehabilitation protocol with limits in range of motion and exercise times after arthroscopic rotator cuff repair would be better for tendon healing without taking any substantial risks. A close communication between the surgeon, the patient and the physical therapy team is important and should continue throughout the whole recovery process.

Passive orientation apparatus

DOEpatents

Spletzer, Barry L.; Fischer, Gary J.; Martinez, Michael A.

2001-01-01

An apparatus that can return a payload to a known orientation after unknown motion, without requiring external power or complex mechanical systems. The apparatus comprises a faceted cage that causes the system to rest in a stable position and orientation after arbitrary motion. A gimbal is mounted with the faceted cage and holds the payload, allowing the payload to move relative to the stable faceted cage. The payload is thereby placed in a known orientation by the interaction of gravity with the geometry of the faceted cage, the mass of the system, and the motion of the payload and gimbal. No additional energy, control, or mechanical actuation is required. The apparatus is suitable for use in applications requiring positioning of a payload to a known orientation after arbitrary or uncontrolled motion, including remote sensing and mobile robot applications.

Measurement of passive ankle stiffness in subjects with chronic hemiparesis using a novel ankle robot

PubMed Central

Roy, Anindo; Bever, Christopher T.; Forrester, Larry W.; Macko, Richard F.; Hogan, Neville

2011-01-01

Our objective in this study was to assess passive mechanical stiffness in the ankle of chronic hemiparetic stroke survivors and to compare it with those of healthy young and older (age-matched) individuals. Given the importance of the ankle during locomotion, an accurate estimate of passive ankle stiffness would be valuable for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. Using a novel ankle robot, we characterized passive ankle stiffness both in sagittal and in frontal planes by applying perturbations to the ankle joint over the entire range of motion with subjects in a relaxed state. We found that passive stiffness of the affected ankle joint was significantly higher in chronic stroke survivors than in healthy adults of a similar cohort, both in the sagittal as well as frontal plane of movement, in three out of four directions tested with indistinguishable stiffness values in plantarflexion direction. Our findings are comparable to the literature, thus indicating its plausibility, and, to our knowledge, report for the first time passive stiffness in the frontal plane for persons with chronic stroke and older healthy adults. PMID:21346215

Commissioning of an integrated platform for time-resolved treatment delivery in scanned ion beam therapy by means of optical motion monitoring.

PubMed

Fattori, G; Saito, N; Seregni, M; Kaderka, R; Pella, A; Constantinescu, A; Riboldi, M; Steidl, P; Cerveri, P; Bert, C; Durante, M; Baroni, G

2014-12-01

The integrated use of optical technologies for patient monitoring is addressed in the framework of time-resolved treatment delivery for scanned ion beam therapy. A software application has been designed to provide the therapy control system (TCS) with a continuous geometrical feedback by processing the external surrogates tridimensional data, detected in real-time via optical tracking. Conventional procedures for phase-based respiratory phase detection were implemented, as well as the interface to patient specific correlation models, in order to estimate internal tumor motion from surface markers. In this paper, particular attention is dedicated to the quantification of time delays resulting from system integration and its compensation by means of polynomial interpolation in the time domain. Dedicated tests to assess the separate delay contributions due to optical signal processing, digital data transfer to the TCS and passive beam energy modulation actuation have been performed. We report the system technological commissioning activities reporting dose distribution errors in a phantom study, where the treatment of a lung lesion was simulated, with both lateral and range beam position compensation. The zero-delay systems integration with a specific active scanning delivery machine was achieved by tuning the amount of time prediction applied to lateral (14.61 ± 0.98 ms) and depth (34.1 ± 6.29 ms) beam position correction signals, featuring sub-millimeter accuracy in forward estimation. Direct optical target observation and motion phase (MPh) based tumor motion discretization strategies were tested, resulting in 20.3(2.3)% and 21.2(9.3)% median (IQR) percentual relative dose difference with respect to static irradiation, respectively. Results confirm the technical feasibility of the implemented strategy towards 4D treatment delivery, with negligible percentual dose deviations with respect to static irradiation.

Dynamic Spatial Hearing by Human and Robot Listeners

NASA Astrophysics Data System (ADS)

Zhong, Xuan

This study consisted of several related projects on dynamic spatial hearing by both human and robot listeners. The first experiment investigated the maximum number of sound sources that human listeners could localize at the same time. Speech stimuli were presented simultaneously from different loudspeakers at multiple time intervals. The maximum of perceived sound sources was close to four. The second experiment asked whether the amplitude modulation of multiple static sound sources could lead to the perception of auditory motion. On the horizontal and vertical planes, four independent noise sound sources with 60° spacing were amplitude modulated with consecutively larger phase delay. At lower modulation rates, motion could be perceived by human listeners in both cases. The third experiment asked whether several sources at static positions could serve as "acoustic landmarks" to improve the localization of other sources. Four continuous speech sound sources were placed on the horizontal plane with 90° spacing and served as the landmarks. The task was to localize a noise that was played for only three seconds when the listener was passively rotated in a chair in the middle of the loudspeaker array. The human listeners were better able to localize the sound sources with landmarks than without. The other experiments were with the aid of an acoustic manikin in an attempt to fuse binaural recording and motion data to localize sounds sources. A dummy head with recording devices was mounted on top of a rotating chair and motion data was collected. The fourth experiment showed that an Extended Kalman Filter could be used to localize sound sources in a recursive manner. The fifth experiment demonstrated the use of a fitting method for separating multiple sounds sources.

Asymmetric otolith function and increased susceptibility to motion sickness during exposure to variations in gravitoinertial acceleration level

NASA Technical Reports Server (NTRS)

Lackner, James R.; Graybiel, Ashton; Johnson, Walter H.; Money, Kenneth E.

1987-01-01

Von Baumgarten and coworkers (1979, 1981) have suggested that asymmetries in otolith function between the left and right labyrinths may result from differences in otoconial mass and could play a role in space motion sickness. Such asymmetries would be centrally compensated for under terrestrial conditions, but on exposure to weightlessness the persisting central compensation would produce a central imbalance that could lead to motion sickness. In this work ocular counterrolling was used as a way of measuring the relative 'efficiency' of the left and right otoliths; the ocular counterrolling scores of individuals were compared with their susceptibility to motion sickness during passive exposure to variations in Gz in parabolic flight maneuvers. The experimental findings indicate that large asymmetries in counterrolling for leftward and rightward body tilts are associated with greater susceptibility to motion sickness in parabolic flight.

Reduction of vortex induced forces and motion through surface roughness control

DOEpatents

Bernitsas, Michael M; Raghavan, Kamaldev

2014-04-01

Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to decrease/suppress Vortex Induced Forces and Motion. Suppression is required when fluid-structure interaction becomes destructive as in VIM of flexible cylinders or rigid cylinders on elastic support, such as underwater pipelines, marine risers, tubes in heat exchangers, nuclear fuel rods, cooling towers, SPAR offshore platforms.

Multisensory effects on somatosensation: a trimodal visuo-vestibular-tactile interaction

PubMed Central

Kaliuzhna, Mariia; Ferrè, Elisa Raffaella; Herbelin, Bruno; Blanke, Olaf; Haggard, Patrick

2016-01-01

Vestibular information about self-motion is combined with other sensory signals. Previous research described both visuo-vestibular and vestibular-tactile bilateral interactions, but the simultaneous interaction between all three sensory modalities has not been explored. Here we exploit a previously reported visuo-vestibular integration to investigate multisensory effects on tactile sensitivity in humans. Tactile sensitivity was measured during passive whole body rotations alone or in conjunction with optic flow, creating either purely vestibular or visuo-vestibular sensations of self-motion. Our results demonstrate that tactile sensitivity is modulated by perceived self-motion, as provided by a combined visuo-vestibular percept, and not by the visual and vestibular cues independently. We propose a hierarchical multisensory interaction that underpins somatosensory modulation: visual and vestibular cues are first combined to produce a multisensory self-motion percept. Somatosensory processing is then enhanced according to the degree of perceived self-motion. PMID:27198907

Window of visibility - A psychophysical theory of fidelity in time-sampled visual motion displays

NASA Technical Reports Server (NTRS)

Watson, A. B.; Ahumada, A. J., Jr.; Farrell, J. E.

1986-01-01

A film of an object in motion presents on the screen a sequence of static views, while the human observer sees the object moving smoothly across the screen. Questions related to the perceptual identity of continuous and stroboscopic displays are examined. Time-sampled moving images are considered along with the contrast distribution of continuous motion, the contrast distribution of stroboscopic motion, the frequency spectrum of continuous motion, the frequency spectrum of stroboscopic motion, the approximation of the limits of human visual sensitivity to spatial and temporal frequencies by a window of visibility, the critical sampling frequency, the contrast distribution of staircase motion and the frequency spectrum of this motion, and the spatial dependence of the critical sampling frequency. Attention is given to apparent motion, models of motion, image recording, and computer-generated imagery.

Passive stiffness of the gastrocnemius muscle in athletes with spastic hemiplegic cerebral palsy.

PubMed

Hussain, A W; Onambele, G L; Williams, A G; Morse, C I

2013-09-01

The passive properties of the muscle-tendon unit are regularly assessed in individuals with cerebral palsy (CP). However, no information is available on the passive properties of adult muscle, and whether any differences exist between the paretic and control muscles. Eleven ambulant male athletes with spastic hemiplegic CP (21.2 ± 3.0 years) and controls without neurological impairment (age = 21.8 ± 2.2 years) completed two and one passive stretch session, respectively. During each session, the ankle was passively dorsiflexed until end range of motion (ROM), whilst recording passive ankle angle, torque and gastrocnemius medialis (GM) myotendinous junction (MTJ) displacement. In addition, GM cross-sectional area (CSA) and length were measured. Subsequently, in vivo stress and strain were determined to calculate elastic modulus. Passive stiffness, MTJ displacement and ROM of the paretic GM were not different from the control muscles. However, the elastic modulus of the paretic GM was two times stiffer than the control GM muscles. In conclusion, athletes with CP exhibit absolute passive muscle stiffness similar to the controls; however, the elastic modulus of the CP muscle was significantly greater. Therefore, throughout the same ROM a smaller GM CSA in CP athletes has to dissipate larger relative torque compared to the control muscles, consequently causing the muscle to elongate to the same extent as the non-paretic muscle under stretch.

Active Flexion in Weight Bearing Better Correlates with Functional Outcomes of Total Knee Arthroplasty than Passive Flexion.

PubMed

Song, Young Dong; Jain, Nimash; Kang, Yeon Gwi; Kim, Tae Yune; Kim, Tae Kyun

2016-06-01

Correlations between maximum flexion and functional outcomes in total knee arthroplasty (TKA) patients are reportedly weak. We investigated whether there are differences between passive maximum flexion in nonweight bearing and other types of maximum flexion and whether the type of maximum flexion correlates with functional outcomes. A total of 210 patients (359 knees) underwent preoperative evaluation and postoperative follow-up evaluations (6, 12, and 24 months) for the assessment of clinical outcomes including maximum knee flexion. Maximum flexion was measured under five conditions: passive nonweight bearing, passive weight bearing, active nonweight bearing, and active weight bearing with or without arm support. Data were analyzed for relationships between passive maximum flexion in nonweight bearing by Pearson correlation analyses, and a variance comparison between measurement techniques via paired t test. We observed substantial differences between passive maximum flexion in nonweight bearing and the other four maximum flexion types. At all time points, passive maximum flexion in nonweight bearing correlated poorly with active maximum flexion in weight bearing with or without arm support. Active maximum flexion in weight bearing better correlated with functional outcomes than the other maximum flexion types. Our study suggests active maximum flexion in weight bearing should be reported together with passive maximum flexion in nonweight bearing in research on the knee motion arc after TKA.

Active Flexion in Weight Bearing Better Correlates with Functional Outcomes of Total Knee Arthroplasty than Passive Flexion

PubMed Central

Song, Young Dong; Jain, Nimash; Kang, Yeon Gwi; Kim, Tae Yune

2016-01-01

Purpose Correlations between maximum flexion and functional outcomes in total knee arthroplasty (TKA) patients are reportedly weak. We investigated whether there are differences between passive maximum flexion in nonweight bearing and other types of maximum flexion and whether the type of maximum flexion correlates with functional outcomes. Materials and Methods A total of 210 patients (359 knees) underwent preoperative evaluation and postoperative follow-up evaluations (6, 12, and 24 months) for the assessment of clinical outcomes including maximum knee flexion. Maximum flexion was measured under five conditions: passive nonweight bearing, passive weight bearing, active nonweight bearing, and active weight bearing with or without arm support. Data were analyzed for relationships between passive maximum flexion in nonweight bearing by Pearson correlation analyses, and a variance comparison between measurement techniques via paired t test. Results We observed substantial differences between passive maximum flexion in nonweight bearing and the other four maximum flexion types. At all time points, passive maximum flexion in nonweight bearing correlated poorly with active maximum flexion in weight bearing with or without arm support. Active maximum flexion in weight bearing better correlated with functional outcomes than the other maximum flexion types. Conclusions Our study suggests active maximum flexion in weight bearing should be reported together with passive maximum flexion in nonweight bearing in research on the knee motion arc after TKA. PMID:27274468

A COMPARATIVE STUDY OF PASSIVE SHOULDER ROTATION RANGE OF MOTION, ISOMETRIC ROTATION STRENGTH AND SERVE SPEED BETWEEN ELITE TENNIS PLAYERS WITH AND WITHOUT HISTORY OF SHOULDER PAIN

PubMed Central

Moreno-Pérez, V.; Elvira, JLL.; Fernandez-Fernandez, J.; Vera-Garcia, FJ.

2018-01-01

Background Glenohumeral internal rotation deficit and external rotation strength have been associated with the development of shoulder pain in overhead athletes. Objective To examine the bilateral passive shoulder rotational range of motion (ROM), the isometric rotational strength and unilateral serve speed in elite tennis players with and without shoulder pain history (PH and NPH, respectively) and compare between dominant and non-dominant limbs and between groups. Study Design Cohort study. Methods Fifty-eight elite tennis players were distributed into the PH group (n = 20) and the NPH group (n = 38). Serve velocity, dominant and non-dominant passive shoulder external and internal rotation (ER and IR) ROM, total arc of motion (TAM: the sum of IR and ER ROM), ER and IR isometric strength, bilateral deficits and ER/IR strength ratio were measured in both groups. Questionnaires were administered in order to classify characteristics of shoulder pain. Results The dominant shoulder showed significantly reduced IR ROM and TAM, and increased ER ROM compared to the non-dominant shoulder in both groups. Isometric ER strength and ER/IR strength ratio were significantly lower in the dominant shoulder in the PH group when compared with the NPH group. No significant differences between groups were found for serve speed. Conclusion These data show specific adaptations in the IR, TAM and ER ROM in the dominant shoulder in both groups. Isometric ER muscle weakness and ER/IR strength ratio deficit appear to be associated with history of shoulder injuries in elite tennis players. It would be advisable for clinicians to use the present information to design injury prevention programs. Level of evidence 2 PMID:29484240

A COMPARATIVE STUDY OF PASSIVE SHOULDER ROTATION RANGE OF MOTION, ISOMETRIC ROTATION STRENGTH AND SERVE SPEED BETWEEN ELITE TENNIS PLAYERS WITH AND WITHOUT HISTORY OF SHOULDER PAIN.

PubMed

Moreno-Pérez, V; Elvira, Jll; Fernandez-Fernandez, J; Vera-Garcia, F J

2018-02-01

Glenohumeral internal rotation deficit and external rotation strength have been associated with the development of shoulder pain in overhead athletes. To examine the bilateral passive shoulder rotational range of motion (ROM), the isometric rotational strength and unilateral serve speed in elite tennis players with and without shoulder pain history (PH and NPH, respectively) and compare between dominant and non-dominant limbs and between groups. Cohort study. Fifty-eight elite tennis players were distributed into the PH group (n = 20) and the NPH group (n = 38). Serve velocity, dominant and non-dominant passive shoulder external and internal rotation (ER and IR) ROM, total arc of motion (TAM: the sum of IR and ER ROM), ER and IR isometric strength, bilateral deficits and ER/IR strength ratio were measured in both groups. Questionnaires were administered in order to classify characteristics of shoulder pain. The dominant shoulder showed significantly reduced IR ROM and TAM, and increased ER ROM compared to the non-dominant shoulder in both groups. Isometric ER strength and ER/IR strength ratio were significantly lower in the dominant shoulder in the PH group when compared with the NPH group. No significant differences between groups were found for serve speed. These data show specific adaptations in the IR, TAM and ER ROM in the dominant shoulder in both groups. Isometric ER muscle weakness and ER/IR strength ratio deficit appear to be associated with history of shoulder injuries in elite tennis players. It would be advisable for clinicians to use the present information to design injury prevention programs. 2.

Clinical assessment of external rotation for the diagnosis of anterior shoulder hyperlaxity.

PubMed

Ropars, M; Fournier, A; Campillo, B; Bonan, I; Delamarche, P; Crétual, A; Thomazeau, H

2010-12-01

The aim of this study was to evaluate two methods of clinical assessment for external rotation of the shoulder to optimise the diagnosis of hyperlaxity in patients being selected for surgery for stabilisation of chronic anterior instability. External rotation was evaluated in 70 healthy student volunteers by two examiners (intertester study) using two methods of assessment at 15-day intervals (intratester study). The first method used was the protocol described for the Instability Severity Index Score (ISIS). In this case, the subject was evaluated in the sitting position, bilaterally with passive range of motion movements. The shoulder was considered hyperlax if ER1 was greater than 85°. With the second, so-called "elbow on the table" (EOT) method, the subject was evaluated in the decubitus dorsal position, unilaterally with passive range of motion. The subject was considered to be hyperlax if ER1 was greater than 90°. Kappa values for intra- and intertester agreement with the ISIS method were average, while they were satisfactory with the intraclass coefficient (ICC). Kappa values for inter- and intratester agreement with the EOT method were average and good, respectively. This tendency was confirmed by the ICC which went from good to excellent for the two examiners in both series of measurements using the EOT method, showing better reproducibility with this method. Our study confirms that the most reproducible method for assessing external rotation is obtained by unilateral assessment of the patient in the decubitus dorsal position, with passive range of motion. An ER1 of 90° is the necessary threshold for hyperlaxity because of elbow retropulsion with this method, which provides immediate and visual evaluation and eliminates the necessity of goniometry. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Passive tendon prosthesis. 888.3025 Section 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Passive tendon prosthesis. 888.3025 Section 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Passive tendon prosthesis. 888.3025 Section 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a...

The effect of talocrural joint manipulation on range of motion at the ankle.

PubMed

Fryer, Gary A; Mudge, Jacob M; McLaughlin, Patrick A

2002-01-01

To determine whether a single high-velocity, low-amplitude thrust manipulation to the talocrural joint altered ankle range of motion. A randomized, controlled and blinded study. Asymptomatic male and female volunteers (N = 41). Subjects were randomly assigned into either an experimental group (n = 20) or a control group (n = 21). Both ankles of subjects in the experimental group were manipulated by using a single high-velocity, low-amplitude thrust to the talocrural joint. Pretest and posttest measurements of passive dorsiflexion range of motion were taken. No significant changes in dorsiflexion range of motion were detected between manipulated ankles and those of control subjects. A significantly greater pretest dorsiflexion range of motion existed in those ankles in which manipulation produced an audible cavitation. Manipulation of the ankle does not increase dorsiflexion range of motion in asymptomatic subjects. Ankles that displayed a greater pretest range of dorsiflexion were more likely to cavitate, raising the possibility that ligament laxity may be associated with the tendency for ankles to cavitate.

Passively Damped Laminated Piezoelectric Shell Structures with Integrated Electric Networks

NASA Technical Reports Server (NTRS)

Saravanos, Dimitris A.

1999-01-01

Multi-field mechanics are presented for curvilinear piezoelectric laminates interfaced with distributed passive electric components. The equations of motion for laminated piezoelectric shell structures with embedded passive electric networks are directly formulated and solved using a finite element methodology. The modal damping and frequencies of the piezoelectric shell are calculated from the poles of the system. Experimental and numerical results are presented for the modal damping and frequency of composite beams with a resistively shunted piezoceramic patch. The modal damping and frequency of plates, cylindrical shells and cylindrical composite blades with piezoelectric-resistor layers are predicted. Both analytical and experimental studies illustrate a unique dependence of modal damping and frequencies on the shunting resistance and show the effect of structural shape and curvature on piezoelectric damping.

Passive microrheology of soft materials with atomic force microscopy: A wavelet-based spectral analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez-Torres, C.; Streppa, L.; Arneodo, A.

2016-01-18

Compared to active microrheology where a known force or modulation is periodically imposed to a soft material, passive microrheology relies on the spectral analysis of the spontaneous motion of tracers inherent or external to the material. Passive microrheology studies of soft or living materials with atomic force microscopy (AFM) cantilever tips are rather rare because, in the spectral densities, the rheological response of the materials is hardly distinguishable from other sources of random or periodic perturbations. To circumvent this difficulty, we propose here a wavelet-based decomposition of AFM cantilever tip fluctuations and we show that when applying this multi-scale methodmore » to soft polymer layers and to living myoblasts, the structural damping exponents of these soft materials can be retrieved.« less

Shoulder range of motion measures as risk factors for shoulder and elbow injuries in high school softball and baseball players.

PubMed

Shanley, Ellen; Rauh, Mitchell J; Michener, Lori A; Ellenbecker, Todd S; Garrison, J Craig; Thigpen, Charles A

2011-09-01

Range of motion deficits in shoulder external rotation (ER), internal rotation (IR), total rotation range of motion (ER + IR), and horizontal adduction (HA) have been retrospectively associated with overhand athletes' arm injuries. The authors expected the incidence of upper extremity injury in high school softball and baseball players with side-to-side shoulder range of motion deficits to be greater than the incidence of upper extremity injury in players with normal shoulder range of motion. Cohort study (prognosis); Level of evidence, 2. High school softball and baseball players (N = 246) participated. Before the start of the season, passive shoulder ER, IR, and HA were assessed at 90° of abduction with the scapula stabilized. Relative risk (RR) was calculated to examine range of motion measure, by categorical criteria, and risk of upper extremity injury. Twenty-seven shoulder and elbow injuries (9 softball, 18 baseball) were observed during the season. The dominant shoulder of all injured players and baseball players displayed a significant decrease in HA (P = .05) and IR (P = .04). The dominant shoulder total rotation of injured baseball players displayed a significant decrease (mean difference = 8.0° ± 0.1°; P = .05) as compared with the dominant shoulder of uninjured baseball players. Players who displayed a decrease of ≥25° of IR in the dominant shoulder were at 4 times greater risk of upper extremity injury compared with players with a <25° decrease in IR, especially for baseball players. While we observed a 1.5 to 2 times increased risk of injury for the 10° to 20° loss in rotational range of motion for the overall sample and baseball, the risk estimates were not statistically significant (P > .05). There are large mean deficits in shoulder IR and HA between injured and noninjured players, but not in ER or total rotation. Passive shoulder IR loss ≥25° as compared bilaterally was predictive of arm injury. Shoulder range of motion deficits differed between sports and appeared more predictive of injury for baseball players.

Experiments and kinematics analysis of a hand rehabilitation exoskeleton with circuitous joints.

PubMed

Zhang, Fuhai; Fu, Yili; Zhang, Qinchao; Wang, Shuguo

2015-01-01

Aiming at the hand rehabilitation of stroke patients, a wearable hand exoskeleton with circuitous joint is proposed. The circuitous joint adopts the symmetric pinion and rack mechanism (SPRM) with the parallel mechanism. The exoskeleton finger is a serial mechanism composed of three closed-chain SPRM joints in series. The kinematic equations of the open chain of the finger and the closed chains of the SPRM joints were built to analyze the kinematics of the hand rehabilitation exoskeleton. The experimental setup of the hand rehabilitation exoskeleton was built and the continuous passive motion (CPM) rehabilitation experiment and the test of human-robot interaction force measurement were conducted. Experiment results show that the mechanical design of the hand rehabilitation robot is reasonable and that the kinematic analysis is correct, thus the exoskeleton can be used for the hand rehabilitation of stroke patients.

Terrain Adaptability Mechanism of Large Ruminants' Feet on the Kinematics View

PubMed Central

Zhang, Qun; Ding, Xilun; Xu, Kun

2015-01-01

Ruminants live in various parts of land. Similar cloven hooves assist ruminants in adapting to different ground environment during locomotion. This paper analyzes the general terrain adaptability of the feet of ruminants using kinematics of the equivalent mechanism model based on screw theory. Cloven hooves could adjust attitude by changing relative positions between two digits in swing phase. This function helps to choose better landing orientation. “Grasping” or “holding” a rock or other object on the ground passively provides extra adhesion force in stance phase. Ruminants could adjust the position of the metacarpophalangeal joint or metatarsophalangeal joint (MTP or MCP) with no relative motion between the tip of feet and the ground, which ensures the adhesion and dexterity in stance phase. These functions are derived from an example from chamois' feet and several assumptions, which are believed to demonstrate the foundation of adaptation of ruminants and ensure a stable and continuous movement. PMID:27019579

Design of rehabilitation robot hand for fingers CPM training

NASA Astrophysics Data System (ADS)

Zhou, Hongfu; Chan, T. W.; Tong, K. Y.; Kwong, K. K.; Yao, Xifan

2008-10-01

This paper presents a low-cost prototype for rehabilitation robot aide patient do hands CPM (continuous passive motion) training. The design of the prototype is based on the principle of Rutgers Master II glove, but it is better in performance for more improvement made. In the design, it uses linear motors to replace pneumatic actuators to make the product more portable and mobile. It increases finger training range to 180 degree for the full range training of hand finger holding and extension. Also the prototype can not only be wearing on palm and fore arm do training for face to face with finger move together, but also be put in the opposite hand glove wear direction for hand rehabilitation training. During the research, Solidworks is used as the tool for mechanical design and movement simulation. It proved through experiment that the prototype made in the research is appropriate for hand do CPM training.

Terrain Adaptability Mechanism of Large Ruminants' Feet on the Kinematics View.

PubMed

Zhang, Qun; Ding, Xilun; Xu, Kun

2015-01-01

Ruminants live in various parts of land. Similar cloven hooves assist ruminants in adapting to different ground environment during locomotion. This paper analyzes the general terrain adaptability of the feet of ruminants using kinematics of the equivalent mechanism model based on screw theory. Cloven hooves could adjust attitude by changing relative positions between two digits in swing phase. This function helps to choose better landing orientation. "Grasping" or "holding" a rock or other object on the ground passively provides extra adhesion force in stance phase. Ruminants could adjust the position of the metacarpophalangeal joint or metatarsophalangeal joint (MTP or MCP) with no relative motion between the tip of feet and the ground, which ensures the adhesion and dexterity in stance phase. These functions are derived from an example from chamois' feet and several assumptions, which are believed to demonstrate the foundation of adaptation of ruminants and ensure a stable and continuous movement.

Wearable Spiral Passive Electromagnetic Sensor (SPES) glove for sign language recognition of alphabet letters and numbers: a preliminary study

NASA Astrophysics Data System (ADS)

Iervolino, Onorio; Meo, Michele

2017-04-01

Sign language is a method of communication for deaf-mute people with articulated gestures and postures of hands and fingers to represent alphabet letters or complete words. Recognizing gestures is a difficult task, due to intrapersonal and interpersonal variations in performing them. This paper investigates the use of Spiral Passive Electromagnetic Sensor (SPES) as a motion recognition tool. An instrumented glove integrated with wearable multi-SPES sensors was developed to encode data and provide a unique response for each hand gesture. The device can be used for recognition of gestures; motion control and well-defined gesture sets such as sign languages. Each specific gesture was associated to a unique sensor response. The gloves encode data regarding the gesture directly in the frequency spectrum response of the SPES. The absence of chip or complex electronic circuit make the gloves light and comfortable to wear. Results showed encouraging data to use SPES in wearable applications.

Proprioception of foot and ankle complex in young regular practitioners of ice hockey, ballet dancing and running.

PubMed

Li, Jing Xian; Xu, Dong Qing; Hoshizaki, Blaine

2009-01-01

This study examined the proprioception of the foot and ankle complex in regular ice hockey practitioners, runners, and ballet dancers. A total of 45 young people with different exercise habits formed four groups: the ice hockey, ballet dancing, running, and sedentary groups. Kinesthesia of the foot and ankle complex was measured in plantarflexion (PF), dorsiflexion (DF), inversion (IV), and eversion (EV) at 0.4 degrees /s using a custom-made device. The results showed the following: (1) significantly better perceived passive motion sense in PF/DF was found as compared with the measurements in IV/EV within each group (P < .01); (2) ice hockey and ballet groups perceived significantly better passive motion sense in IV/EV than the running (P < .05) and the sedentary (P < .01) groups; and (3) no significant difference in the all measurements was found between running and sedentary groups. The benefits of ice hockey and ballet dancing on proprioception may be associated with their movement characteristics.

Passive range estimation for rotorcraft low-altitude flight

NASA Technical Reports Server (NTRS)

Sridhar, B.; Suorsa, R.; Hussien, B.

1991-01-01

The automation of rotorcraft low-altitude flight presents challenging problems in control, computer vision and image understanding. A critical element in this problem is the ability to detect and locate obstacles, using on-board sensors, and modify the nominal trajectory. This requirement is also necessary for the safe landing of an autonomous lander on Mars. This paper examines some of the issues in the location of objects using a sequence of images from a passive sensor, and describes a Kalman filter approach to estimate the range to obstacles. The Kalman filter is also used to track features in the images leading to a significant reduction of search effort in the feature extraction step of the algorithm. The method can compute range for both straight line and curvilinear motion of the sensor. A laboratory experiment was designed to acquire a sequence of images along with sensor motion parameters under conditions similar to helicopter flight. Range estimation results using this imagery are presented.

Effect of wrist and interphalangeal thumb movement on zone T2 flexor pollicis longus tendon tension in a human cadaver model.

PubMed

Rappaport, Patricia O; Thoreson, Andrew R; Yang, Tai-Hua; Reisdorf, Ramona L; Rappaport, Stephen M; An, Kai-Nan; Amadio, Peter C

2015-01-01

Therapy after flexor pollicis longus (FPL) repair typically mimics finger flexor management, but this ignores anatomic and biomechanical features unique to the FPL. We measured FPL tendon tension in zone T2 to identify biomechanically appropriate exercises for mobilizing the FPL. Eight human cadaver hands were studied to identify motions that generated enough force to achieve FPL movement without exceeding hypothetical suture strength. With the carpometacarpal and metacarpophalangeal joints blocked, appropriate forces were produced for both passive interphalangeal (IP) motion with 30° wrist extension and simulated active IP flexion from 0° to 35° with the wrist in the neutral position. This work provides a biomechanical basis for safely and effectively mobilizing the zone T2 FPL tendon. Our cadaver study suggests that it is safe and effective to perform early passive and active exercise to an isolated IP joint. NA. Copyright © 2015 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Active Motion Control of Tetrahymena pyriformis by Galvanotaxis and Geotaxis

NASA Astrophysics Data System (ADS)

Kim, Jihoon; Byun, Doyoung; Kim, Min Jun

2013-11-01

Recently, there has been increasing interest in the swimming behavior of microorganisms and biologically inspired micro-robots. These microorganisms naturally accompanied by complex motions. Therefore it is important to understand the flow characteristics as well as control mechanisms. One of eukaryotic cells, the protozoa are a diverse group of unicellular organisms, many of which are motile cilia. Motile cilia are cover on the surface of cell in large numbers and beat in oriented waves. Sequential beating motions of a single cilium form metachronal strokes, producing a propagation wave, and therefore the body is achieved propulsion force. So preliminary studies are achieved to understand the flow induced by swimming microorganisms. Based on hydrodynamic results, the follow study of a few micro-scale protozoa cell, such as the Tetrahymena pyriformis, has provided active or passive control into several external stimuli. In typical control methods, the galvanotaxis and geotaxis were adopted active and passive control, respectively. The validation of galvanotaxis is used DC and AC voltage. In terms of geotaxis, corrugated microstructures were used to control in the microchannel. This research was supported by the Ministry of Education, Science and Technology (MEST, 2011-0016461), National Science Foundation (NSF) CMMI Control Systems Program (#1000255) and Army Research Office (W911NF-11-1-0490).

ACUTE CHANGES IN PASSIVE GLENOHUMERAL ROTATION FOLLOWING TENNIS PLAY EXPOSURE IN ELITE FEMALE PLAYERS

PubMed Central

Kibler, W. Ben; Myers, Natalie L.; Smith, Belinda J.

2016-01-01

Background Alterations in glenohumeral (GH) rotation especially internal rotation and total range of motion have been associated with altered GH kinematics and susceptibility to injury. Researchers have evaluated long-term change in baseball and tennis players, and short-term changes in baseball players. However, acute (short-term) changes in GH rotation have not been evaluated in tennis players. Hypotheses/Purpose The purpose of this study was to quantify short-term glenohumeral rotational changes within a group of professional women's tennis players following competitive play. It was hypothesized that there would be acute alterations in passive glenohumeral internal rotation and total range of motion following episodes of tennis play. Study Design Cohort Study Methods Passive glenohumeral external rotation (GER), glenohumeral internal rotation (GIR), and total range of motion (TROM) were evaluated in a cohort of 79 professional adult female tennis players. Measurements were taken at three different time points (TP): baseline before match play (TP1), immediately after match play (TP2), and 24-hours after baseline (TP3). Results There was a statistically significant decrease in the mean GIR from TP1 (43 ± 11 °) to TP2 (39 ± 9 °) (p=0.002) and from TP1 to TP3 (38 ± 10 °) (p=0.001). All measures were at the level of minimal detectable change (MDC) (4 °) indicating clinical significance. There was a decrease in mean TROM from TP1 (146 ± 11 °) to TP2 (142 ± 12 °) (p=0.04), which was not above MDC (7 °). Subgroup analysis showed that 47% of the players demonstrated a decrease in GIR beyond MDC, and 37% demonstrated a decrease in TROM beyond MDC. GER remained unchanged across all time points (p>0.05). Conclusion Both GIR and TROM were reduced after acute exposure to tennis play. In a large subgroup of the cohort, the changes were clinically significant and approached values previously demonstrated to be associated with increased injury risk. Given the changes in glenohumeral motion following acute exposure to tennis, evaluation of players for significant motion alterations following overhead activity and intervention strategies to minimize such alterations in these players are recommended for high level tennis players. Level of evidence Level 3 PMID:27104056

Tobacco Use and Environmental Smoke Exposure among Taiwanese Pregnant Smokers and Recent Quitters: Risk Perception, Attitude, and Avoidance Behavior

PubMed Central

Lai, Ming-Cheng; Chou, Feng-Sha; Yang, Yann-Jy; Wang, Chih-Chien; Lee, Ming-Chang

2013-01-01

In this study, we conducted an empirical survey of the avoidance behaviors and risk perceptions of active and passive smoking pregnant smokers and recent quitters. We employed an online questionnaire survey by recruiting 166 voluntary participants from an online parenting community in Taiwan. The results of the empirical survey revealed that three-fourths of smokers quit smoking during pregnancy and one-fourth continued smoking. All pregnant women who continued smoking had partners or lived with relatives who smoked. Current smokers and quitters differed significantly in their risk perceptions and attitudes toward smoking during pregnancy. Most pregnant smokers and quitters adopted passive smoking avoidance behaviors at home and in public. Nevertheless, one-fifth of pregnant women chose not to avoid passive smoking. We concluded that most women stop smoking during pregnancy; however, most women continue to be exposed to passive-smoking environments. Perceived fetal health risks and attitudes toward smoking during pregnancy are critical predictors of the anti-smoking behaviors of pregnant women. PMID:24005830

Individualistic weight perception from motion on a slope

PubMed Central

Zintus-art, K.; Shin, D.; Kambara, H.; Yoshimura, N.; Koike, Y.

2016-01-01

Perception of an object’s weight is linked to its form and motion. Studies have shown the relationship between weight perception and motion in horizontal and vertical environments to be universally identical across subjects during passive observation. Here we show a contradicting finding in that not all humans share the same motion-weight pairing. A virtual environment where participants control the steepness of a slope was used to investigate the relationship between sliding motion and weight perception. Our findings showed that distinct, albeit subjective, motion-weight relationships in perception could be identified for slope environments. These individualistic perceptions were found when changes in environmental parameters governing motion were introduced, specifically inclination and surface texture. Differences in environmental parameters, combined with individual factors such as experience, affected participants’ weight perception. This phenomenon may offer evidence of the central nervous system’s ability to choose and combine internal models based on information from the sensory system. The results also point toward the possibility of controlling human perception by presenting strong sensory cues to manipulate the mechanisms managing internal models. PMID:27174036

Neural network-based motion control of an underactuated wheeled inverted pendulum model.

PubMed

Yang, Chenguang; Li, Zhijun; Cui, Rongxin; Xu, Bugong

2014-11-01

In this paper, automatic motion control is investigated for one of wheeled inverted pendulum (WIP) models, which have been widely applied for modeling of a large range of two wheeled modern vehicles. First, the underactuated WIP model is decomposed into a fully actuated second order subsystem Σa consisting of planar movement of vehicle forward and yaw angular motions, and a nonactuated first order subsystem Σb of pendulum motion. Due to the unknown dynamics of subsystem Σa and the universal approximation ability of neural network (NN), an adaptive NN scheme has been employed for motion control of subsystem Σa . The model reference approach has been used whereas the reference model is optimized by the finite time linear quadratic regulation technique. The pendulum motion in the passive subsystem Σb is indirectly controlled using the dynamic coupling with planar forward motion of subsystem Σa , such that satisfactory tracking of a set pendulum tilt angle can be guaranteed. Rigours theoretic analysis has been established, and simulation studies have been performed to demonstrate the developed method.

Instant axis of rotation of L4-5 motion segment--a biomechanical study on cadaver lumbar spine.

PubMed

Sengupta, Dilip K; Demetropoulos, Constantine K; Herkowitz, Harry N

2011-06-01

The instant axis of rotation (IAR) is an important kinematic property to characterise of lumbar spine motion. The goal of this biomechanical study on cadaver lumbar spine was to determine the excursion of the IAR for flexion (FE), lateral bending (LB) and axial rotation (AR) motion at L4-5 segment. Ten cadaver lumbar spine specimens were tested in a 6 degrees-of-freedom spine tester with continuous clyclical loading using pure moment and follower pre-load, to produce physiological motion. The specimens were x-rayed and CT scanned prior to testing to identify marker position. Continuous motion tracking was done by Optotrak motion capture device. A continuous tracking of the IAR excursion was calculated from the continuous motions capturedata using a computer programme. IAR translates forward in flexion and backwards in extension with mean excursion of 26.5 mm (+/- 5.6 SD). During LB motion, IAR translates laterally in the same direction, and the mean excursion was 15.35 mm (+/- 8.75 SD). During axial rotation the IAR translates in the horizontal plane in a semicircular arc, around the centre of the vertebral body, but the IAR translates in the opposite direction of rotation. The IAR excursion was faster and larger during neutral zone motion in FE and LB, but uniform for AR motion. This is the first published data on the continuous excursion of IAR of a lumbar motion segment. The methodology is accurate and precise, but not practicable for in vivo testing.

UCSD High Energy X-ray Timing Experiment magnetic shield design and test results

NASA Technical Reports Server (NTRS)

Rothschild, Richard E.; Pelling, Michael R.; Hink, Paul L.

1991-01-01

Results are reported from an effort to define a passive magnetic field concept for the High Energy X-ray Timing Experiment (HEXTE), in the interest of reducing the detector-gain variations due to 0.5-1.0-sec timescale magnetic field variations. This will allow a sensitivity of the order of 1 percent of the HEXTE background. While aperture modulation and automatic gain control will minimize effects on timescales of tens of seconds and longer, passive magnetic shielding of the photomultiplier tubes will address 1-sec timescale variations due to aperture motions.

Calcifying supracoracoid bursitis as a cause of chronic shoulder pain.

PubMed Central

Mens, J; van der Korst, J K

1984-01-01

A case of chronic shoulder pain is reported with marked limitation of both active and passive elevations and a normal range of motion of the glenohumeral joint. X-ray examination demonstrated cloudy calcification in the coracoclavicular region, presumably indicating calcifying supracoracoid bursitis. Images PMID:6497468

10 CFR 431.62 - Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... occupancy sensor means a device which uses passive infrared, ultrasonic, or other motion-sensing technology..., frozen, combination chilled and frozen, or variable temperature; (4) Displays or stores merchandise and... doors; (6) Is designed for pull-down temperature applications or holding temperature applications; and...

40 CFR 78.15 - Motions in evidentiary hearings.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Motions in evidentiary hearings. 78.15 Section 78.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPEAL PROCEDURES § 78.15 Motions in evidentiary hearings. (a) Any party may make a motion to the...

Effectiveness of Music Listening in Patients With Total Knee Replacement During CPM Rehabilitation.

PubMed

Hsu, Chih-Chung; Chen, Wei-Ming; Chen, Su-Ru; Tseng, Yen-Ting; Lin, Pi-Chu

2016-01-01

This study investigated the effects of music listening on the anxiety, heart rate variability (HRV), and joint range of motion (ROM) of patients undergoing continuous passive motion (CPM) after total knee replacement surgery. An experimental design was used. Participants in the experimental group (n = 49) listened to music from 10 min before receiving CPM until the end of the session (25 min in total) on the first and second day following surgery, whereas participants in the control group (n = 42) did not listen to music but rested quietly in bed starting 10 min before and throughout CPM. Compared with the control group, the experimental group exhibited significantly lower anxiety levels (p < .05) and increased CPM angles (p < .05) during treatment and increased active flexion ROM (p < .05) upon discharge. The low-frequency (LF)/high-frequency (HF) power ratio, normalized LF HRV, and normalized HF HRV of the two groups differed significantly, indicating that the patients in the experimental group had greater parasympathetic activity compared with those in the control group. Music listening can effectively reduce patient anxiety and enhance the ROM of their joints during postoperative rehabilitation. Health-care practitioners should consider including music listening as a routine practice for postoperative rehabilitation following orthopedic surgery. © The Author(s) 2015.

Blood, bugs, and motion - what do we really know in regard to total joint arthroplasty?

PubMed

Glassner, Philip J; Slover, James D; Bosco, Joseph A; Zuckerman, Joseph D

2011-01-01

In total joint arthroplasty, it is often necessary to formulate decisions that are not clearly evidence-based. This review presents some current controversial topics in total joint arthroplasty, including preoperative autologous blood donation versus erythropoietin (EPO) usage, preoperative screening and treatment for methicillin resistant Staphylococcus aureus (MRSA), and the use of continuous passive motion (CPM) following total knee arthroplasty, providing an evidence-based guide for the treating orthopaedic surgeon. Our review shows that preoperative autologous blood donation is over utilized, with EPO being under utilized. Surgeons are encouraged to develop patient-specific strategies, which have been shown to decrease transfusion rates, reduce wasted autologous blood, and increase EPO use. Definitive conclusions regarding MRSA screening for orthopaedic patients cannot be drawn; but due to the significant cost and morbidity associated with a postoperative MRSA infection, we believe a screen and treat protocol should be considered for all patients being admitted to the hospital for elective or emergent surgery. Short-term (3 to 5 days) inpatient use of CPM is recommended at this time. It is low-cost, has minimal risk, and may be a factor in decreasing the length of stay, potentially leading to significant cost savings. However, no long-term benefits of CPM use have been established.

Microwelding of various metallic materials under ultravacuum (AO 138-10)

NASA Technical Reports Server (NTRS)

Assie, Jean Pierre; Conde, Eric

1991-01-01

The first finding from the AO 138-10 is that cold welding never occurred, and that microwelds didn't even affect the reference (presumably microweld prone) pairs of metals consisting of gold, silver, and chromium. The scientific disappointment from these results must be tempered by the notion of a static AO 138-10 experiment, reflecting the passive character of the global Long Duration Exposure Facility (LDEF) flight. Thus far, it has been theorized that cold welding results from the peeling of the oxide layer, that is formed in an earth environment, by the space environment since such a layer no longer grows in space. In fact, such stripping of the oxide layer supposes relative motion of the contacting materials. In the absence of such motion, as in this experiment, oxidation will preserve its integrity and continue to prevent microwelding. More bewildering is that there was no microwelding of the reference pairs. Even though AO 138-10 failed scientific expectations, as did the LDEF structure with cold welding, the positive, functional aspect to keep in mind is the safe operation of single-shot (appendage releasing and/or latching) mechanisms, unhindered by microwelding in a space vacuum, as now demonstrated by the statically representative pairs of materials. Other aspects of the experiment are discussed.

Lunar Laser Ranging: Glorious Past And A Bright Future

NASA Astrophysics Data System (ADS)

Shelus, Peter J.

Lunar Laser Ranging (LLR), a part of the NASA Apollo program, has beenon-going for more than 30 years. It provides the grist for a multi-disciplinarydata analysis mill. Results exist for solid Earth sciences, geodesy and geodynamics,solar system ephemerides, terrestrial and celestial reference frames, lunar physics,general relativity and gravitational theory. Combined with other data, it treatsprecession of the Earth''s spin axis, lunar induced nutation, polar motion/Earthrotation, Earth orbit obliquity to the ecliptic, intersection of the celestial equatorwith the ecliptic, luni-solar solid body tides, lunar tidal deceleration, lunar physicaland free librations, structure of the moon and energy dissipation in the lunar interior.LLR provides input to lunar surface cartography and surveying, Earth station and lunar retroreflector location and motion, mass of the Earth-moon system, lunar and terrestrial gravity harmonics and Love numbers, relativistic geodesic precession, and the equivalence principle of general relativity. With the passive nature of the reflectors and steady improvement in observing equipment and data analysis, LLR continues to provide state-of-the-art results. Gains are steady as the data-base expands. After more than 30 years, LLR remains the only active Apollo experiment. It is important to recognize examples of efficient and cost effective progress of research. LLR is just such an example.

Ego-Motion and Tracking for Continuous Object Learning: A Brief Survey

DTIC Science & Technology

2017-09-01

ARL-TR-8167• SEP 2017 US Army Research Laboratory Ego-motion and Tracking for ContinuousObject Learning: A Brief Survey by Jason Owens and Philip...SEP 2017 US Army Research Laboratory Ego-motion and Tracking for ContinuousObject Learning: A Brief Survey by Jason Owens and Philip OsteenVehicle...

Innovative flow controller for time integrated passive sampling using SUMMA canisters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simon, P.; Farant, J.P.; Cole, H.

1996-12-31

To restrict the entry of gaseous contaminants inside evacuated vessels such as SUMMA canisters, mechanical flow controllers are used to collect integrated atmospheric samples. From the passive force generated by the pressure gradient, the motion of gas can be controlled to obtain a constant flow rate. Presently, devices based on the principle of critical orifices are used and they are all limited to an upper integrated sampling time. A novel flow controller which can be designed to achieve any desired sampling time when used on evacuated vessels was recently developed. It can extend the sampling time for hours, days, weeksmore » or even months for the benefits of environmental, engineering and toxicological professionals. The design of the controller is obtained from computer simulations done with an original set of equations derived from fluid mechanic and gas kinetic laws. To date, the experimental results have shown excellent agreement, with predictions obtained from the mathematical model. This new controller has already found numerous applications. Units able to deliver a constant sampling rate between vacuum and approximately -10 inches Hg during continuous long term duration have been used with SUMMA canisters of different volumes (500 ml, 1 litre and 61). Essentially, any combination of sampling time and sampler volume is possible. The innovative flow controller has contributed to an air quality assessment around a sanitary landfill (indoor/outdoor), and inside domestic wastewater and pulpmill sludge treatment facilities. It is presently being used as an alternative methodology for atmospheric sampling in the Russian orbital station Mir. This device affords true long term passive monitoring of selected gaseous air pollutants for environmental studies. 14 refs., 3 figs.« less

Swimming in an Unsteady World.

PubMed

Koehl, M A R; Cooper, T

2015-10-01

When animals swim in aquatic habitats, the water through which they move is usually flowing. Therefore, an important part of understanding the physics of how animals swim in nature is determining how they interact with the fluctuating turbulent water currents in their environment. We addressed this issue using microscopic larvae of invertebrates in "fouling communities" growing on docks and ships to ask how swimming affects the transport of larvae between moving water and surfaces from which they disperse and onto which they recruit. Field measurements of the motion of water over fouling communities were used to design realistic turbulent wavy flow in a laboratory wave-flume over early-stage fouling communities. Fine-scale measurements of rapidly-varying water-velocity fields were made using particle-image velocimetry, and of dye-concentration fields (analog for chemical cues from the substratum) were made using planar laser-induced fluorescence. We used individual-based models of larvae that were swimming, passively sinking, passively rising, or were passive and neutrally buoyant to determine how their trajectories were affected by their motion through the water, rotation by local shear, and transport by ambient flow. Swimmers moved up and down in the turbulent flow more than did neutrally buoyant larvae. Although more of the passive sinkers landed on substrata below them, and more passive risers on surfaces above, swimming was the best strategy for landing on surfaces if their location was not predictable (as is true for fouling communities). When larvae moved within 5 mm of surfaces below them, passive sinkers and neutrally-buoyant larvae landed on the substratum, whereas many of the swimmers were carried away, suggesting that settling larvae should stop swimming as they near a surface. Swimming and passively-rising larvae were best at escaping from a surface below them, as precompetent larvae must do to disperse away. Velocities, vorticities, and odor-concentrations encountered by larvae fluctuated rapidly, with peaks much higher than mean values. Encounters with concentrations of odor or with vorticities above threshold increased as larvae neared the substratum. Although microscopic organisms swim slowly, their locomotory behavior can affect where they are transported by the movement of ambient water as well as the signals they encounter when they move within a few centimeters of surfaces. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Semi Active Control of Civil Structures, Analytical and Numerical Studies

NASA Astrophysics Data System (ADS)

Kerboua, M.; Benguediab, M.; Megnounif, A.; Benrahou, K. H.; Kaoulala, F.

Structural control for civil structures was born out of a need to provide safer and more efficient designs with the reality of limited resources. The purpose of structural control is to absorb and to reflect the energy introduced by dynamic loads such as winds, waves, earthquakes, and traffic. Today, the protection of civil structures from severe dynamic loading is typically achieved by allowing the structures to be damaged. Semi-active control devices, also called "smart" control devices, assume the positive aspects of both the passive and active control devices. A semi-active control strategy is similar to the active control strategy. Only here, the control actuator does not directly apply force to the structure, but instead it is used to control the properties of a passive energy device, a controllable passive damper. Semi-active control strategies can be used in many of the same civil applications as passive and active control. One method of operating smart cable dampers is in a purely passive capacity, supplying the dampers with constant optimal voltage. The advantages to this strategy are the relative simplicity of implementing the control strategy as compared to a smart or active control strategy and that the dampers are more easily optimally tuned in- place, eliminating the need to have passive dampers with unique optimal damping coefficients. This research investigated semi-active control of civil structures for natural hazard mitigation. The research has two components, the seismic protection of buildings and the mitigation of wind-induced vibration in structures. An ideal semi-active motion equation of a composite beam that consists of a cantilever beam bonded with a PZT patch using Hamilton's principle and Galerkin's method was treated. A series R-L and a parallel R-L shunt circuits are coupled into the motion equation respectively by means of the constitutive relation of piezoelectric material and Kirchhoff's law to control the beam vibration. A numerical example of the parallel R-L piezoelectric vibration shunt control simulated with MATLAB® is presented. An analytical study of the resistor-inductor (R-L) passive piezoelectric vibration shunt control of a cantilever beam was undertaken. The modal and strain analyses were performed by varying the material properties and geometric configurations of the piezoelectric transducer in relation to the structure in order to maximize the mechanical strain produced in the piezoelectric transducer.

46 CFR 170.295 - Special consideration for free surface of passive roll stabilization tanks.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Special consideration for free surface of passive roll stabilization tanks. 170.295 Section 170.295 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... consideration for free surface of passive roll stabilization tanks. (a) The virtual increase in the vertical...

Guideline recommendations for post-acute postoperative physiotherapy in total hip and knee arthroplasty: are they used in daily clinical practice?

PubMed

Peter, W F; Nelissen, R G H H; Vlieland, T P M Vliet

2014-09-01

In a Dutch guideline on physiotherapy (PT) in hip and knee osteoarthritis, a number of recommendations on post-acute (i.e. after discharge from hospital) PT following total hip (THA) and total knee (TKA) arthroplasty were included. Little is known about the uptake of these recommendations in daily clinical practice. The aim of the present study was to determine the extent to which the guideline recommendations regarding post-acute PT after THA and TKA are followed in daily clinical practice. An online pilot survey on the delivery of post-acute, postoperative PT was sent to a random sample of 957 Dutch physiotherapists. The survey included questions on the application of recommended, neither recommended nor advised against, and advised against treatment modalities and various treatment modalities for which there were no formulated recommendations. A total of 219 physiotherapists completed the questionnaire, with a mean age of 40 years (standard deviation 12.6), 55% female and 95% working in primary care. The vast majority reported the use of the recommended exercise modalities (muscle strengthening exercises (96%), and functional exercises (99%). Continuous passive motion, which was neither recommended nor advised against, and electrical muscle stimulation, which was not recommended, were provided by 1%. Reported treatment modalities for which there were no formulated recommendations included patient education (99%), gait training (95%), active range of motion (ROM) exercises (93%), balance exercises (86%), passive ROM exercises (58%), aerobic exercises (50%), massage (18%) and cold therapy (11%). The vast majority of physiotherapists reported adhering to recommendations on post-acute postoperative PT in THA and TKA patients after discharge from hospital. Although yet to be confirmed in a larger nationwide survey, the relatively high frequency of use of many other treatment modalities, for which there were no formulated recommendations, suggests the need to extend the current set of recommendations to include evidence-based statements on additional treatment modalities. Copyright © 2014 John Wiley & Sons, Ltd.

Diode-pumped continuous wave and passively Q-switched Tm, Mg: LiTaO₃ lasers.

PubMed

Feng, T; Li, T; Zhao, S; Li, Q; Yang, K; Zhao, J; Qiao, W; Hang, Y; Zhang, P; Wang, Y; Xu, J

2014-02-24

We have demonstrated the continuous wave and passively Q-switched Tm, Mg: LiTaO3 lasers for the first time. In continuous wave (CW) regime, a maximum CW output power of 1.03 W at 1952 nm was obtained, giving a slope efficiency of 9.5% and a beam quality M2 = 2.2. In passive Q-switching regime, a single walled carbon nanotube (SWCNT) was employed as saturable absorber (SA). The Tm,Mg:LiTaO3 laser has yielded a pulse of 560 ns under repetition rate of 34.2 kHz at 1926 nm, corresponding to a single pulse energy of 10.1 μJ. The results indicate a promising potential of nonlinear crystals in the applications for laser host materials.

Passive damping concepts for free and forced member and grillage vibration

NASA Technical Reports Server (NTRS)

Razzaq, Zia; Najjar, Bassam

1988-01-01

The performance of potential passive damping concepts is investigted for a long tubular aluminum alloy member, and a two-bar grillage structure. The members are restrained partially at the ends and are of the type being considered by NASA for possible use in the construction of a future space station. Four different passive damping concepts are studied and include nylon brush, wool swab, copper brush, and silly putty in chamber dampers. Both free and forced vibration tests are conducted. It is found that the silly putty in chamber damper concept provides considerably greater passive damping as compared to that of the other three concepts. For the grillage natural vibration, a five wool swab damper configuration provides greater damping than the five silly putty dampers in chamber configuration. Due to the constrained motion imposed by the vibrator used in the tests, the effectiveness of the passive dampers could not be adequately evaluated for the individual member. However, it is found that for the grillage under forced vibration, the five silly putty dampers in chamber damper configuration provides very effective passive damping although only at and around the resonant frequency. At resonance, these dampers provide a 51 percent reduction in the dynamic magnification factor for this case.

Bone structure and quality preserved by active versus passive muscle exercise in 21 days tail-suspended rats

NASA Astrophysics Data System (ADS)

Luan, Huiqin; Sun, Lian-wen; Fan, Yu-bo

2012-07-01

Humans in Space suffer from microgravity-induced attenuated bone strength that needs to be addressed by on-orbit exercise countermeasures. However, exercise prescriptions so far did not adequately counteract the bone loss of astronauts in spaceflight because even active muscle contractions were converted to passive mode during voluntary bouts. We tested our hypothesis in unloaded rat hind limb following twenty-one days of tail-suspension (TS) combined with exercise using a hind limb stepper device designed by our group. Female Sprague Dawley rats (250g b.wt.) were divided into four groups (n=5, each): TS-only (hind limb unloading), TS plus passive mode exercise (TSP) induced by mechanically-forced passive hind limb lifting, TS plus active mode exercise (TSA) entrained by plantar electrostimulation, and control (CON) group. Standard measures of bone (e.g., mineral density, trabecular microstructure, biomechanics and ash weight) were monitored. Results provided that the attenuated properties of unloaded hind limb bone in TS-rats were more effectively supported by active mode than by passive mode motions. We here propose a modified exercise regimen combined with spontaneous muscle contractions thereby considering the biodynamic demands of both muscle and bone during resistive-load exercise in microgravity. Keywords: rat, BMD, DXA, passive exercise, active exercise, bone loss, tail suspension, spaceflight analogue, exercise countermeasure.

Electrophysiological Correlates of the Threshold to Detection of Passive Motion: An Investigation in Professional Volleyball Athletes with and without Atrophy of the Infraspinatus Muscle

PubMed Central

Salles, José Inácio; Cossich, Victor Rodrigues Amaral; Amaral, Marcus Vinicius; Monteiro, Martim T.; Cagy, Maurício; Motta, Geraldo; Velasques, Bruna; Piedade, Roberto; Ribeiro, Pedro

2013-01-01

The goal of the present study is to compare the electrophysiological correlates of the threshold to detection of passive motion (TTDPM) among three groups: healthy individuals (control group), professional volleyball athletes with atrophy of the infraspinatus muscle on the dominant side, and athletes with no shoulder pathologies. More specifically, the study aims at assessing the effects of infraspinatus muscle atrophy on the cortical representation of the TTDPM. A proprioception testing device (PTD) was used to measure the TTDPM. The device passively moved the shoulder and participants were instructed to respond as soon as movement was detected (TTDPM) by pressing a button switch. Response latency was established as the delay between the stimulus (movement) and the response (button press). Electroencephalographic (EEG) and electromyographic (EMG) activities were recorded simultaneously. An analysis of variance (ANOVA) and subsequent post hoc tests indicated a significant difference in latency between the group of athletes without the atrophy when compared both to the group of athletes with the atrophy and to the control group. Furthermore, distinct patterns of cortical activity were observed in the three experimental groups. The results suggest that systematically trained motor abilities, as well as the atrophy of the infraspinatus muscle, change the cortical representation of the different stages of proprioceptive information processing and, ultimately, the cortical representation of the TTDPM. PMID:23484136

Translational damping on high-frequency flapping wings

NASA Astrophysics Data System (ADS)

Parks, Perry A.

Flapping fliers such as insects and birds depend on passive translational and rotational damping to terminate quick maneuvers and to provide a source of partial stability in an otherwise unstable dynamic system. Additionally, passive translational and rotational damping reduce the amount of active kinematic changes that must be made to terminate maneuvers and maintain stability. The study of flapping-induced damping phenomena also improves the understanding of micro air vehicle (MAV) dynamics needed for the synthesis of effective flight control strategies. Aerodynamic processes which create passive translational and rotational damping as a direct result of symmetric flapping with no active changes in wing kinematics have been previously studied and were termed flapping counter-force (FCF) and flapping counter-torque (FCT), respectively. In this first study of FCF measurement in air, FCF generation is measured using a pendulum system designed to isolate and measure the relationship of translational flapping-induced damping with wingbeat frequency for a 2.86 gram mechanical flapper equipped with real cicada wings. Analysis reveals that FCF generation and wingbeat frequency are directly proportional, as expected from previous work. The quasi-steady FCF model using Blade-Element-Theory is used as an estimate for translational flapping-induced damping. In most cases, the model proves to be accurate in predicting the relationship between flapping-induced damping and wingbeat frequency. "Forward-backward" motion proves to have the strongest flapping-induced damping while "up-down" motion has the weakest.

Sciatic nerve stiffness is not changed immediately after a slump neurodynamics technique

PubMed Central

Neto, Tiago; Freitas, Sandro R; Andrade, Ricardo J; Gomes, João; Vaz, João; Mendes, Bruno; Firmino, Telmo; Nordez, Antoine; Oliveira, Raúl

2017-01-01

Summary Background Neurodynamics techniques aim to assess and improve neural mechanosensitivity. However, there is no in vivo evidence regarding the mechanical effects of these techniques in the nerve stiffness. This study examined the immediate effects of a slump neurodynamics technique in the sciatic nerve shear wave velocity (SWV. i.e. an index of stiffness) using ultrasound-based elastography. Methods Fourteen healthy participants were included in this experiment. Sciatic SWV and ankle passive torque were measured during a passive ankle dorsiflexion motion (2°/s), before and immediately after 3 minutes of slump neurodynamics technique, randomly applied to one lower limb. The contralateral limb served as control. Results The slump intervention did not change the sciatic SWV (P=0.78), nor the dorsiflexion passive torque (P=0.14), throughout the ankle dorsiflexion motion. Excellent values of intra-rater repeatability (ICC=0.88, 0.68–0.96), and low values of standard error of measurement (0.59 m/s, 0.35–1.15m/s), were observed for the SWV measurements. Conclusions The sciatic nerve stiffness of healthy participants did not change immediately after a slump neurodynamics technique, suggesting a compliance of the neural tissue to tensile loads. However, these results ought to be confirmed using other neurodynamics techniques and in other populations (e.g. peripheral neuropathies). Level of evidence III. PMID:29387655

A simultaneous spin/eject mechanism for aerospace payloads

NASA Technical Reports Server (NTRS)

Palmer, G. D.; Banks, T. N.

1976-01-01

A simultaneous spin/eject mechanism was developed for aerospace applications requiring a compact, passive device which would accommodate payload support and controlled-release functions, and which would provide a highly accurate spin-ejection motion to the payload. The mechanism satisfied the requirements and is adaptable to other deployment applications.

Mixing of a passive scalar in isotropic and sheared homogeneous turbulence

NASA Technical Reports Server (NTRS)

Shirani, E.; Ferziger, J. H.; Reynolds, W. C.

1981-01-01

In order to calculate the velocity and scalar fields, the three dimensional, time-dependent equations of motion and the diffusion equation were solved numerically. The following cases were treated: isotropic, homogeneous turbulence with decay of a passive scalar; and homogeneous turbulent shear flow with a passive scalar whose mean varies linearly in the spanwise direction. The solutions were obtained at relatively low Reynolds numbers so that all of the turbulent scales could be resolved without modeling. Turbulent statistics such as integral length scales, Taylor microscales, Kolmogorov length scale, one- and two-point correlations of velocity-velocity and velocity-scalar, turbulent Prandtl/Schmidt number, r.m.s. values of velocities, the scalar quantity and pressure, skewness, decay rates, and decay exponents were calculated. The results are compared with the available expermental results, and good agreement is obtained.

Passive appendages generate drift through symmetry breaking

PubMed Central

Lācis, U.; Brosse, N.; Ingremeau, F.; Mazzino, A.; Lundell, F.; Kellay, H.; Bagheri, S.

2014-01-01

Plants and animals use plumes, barbs, tails, feathers, hairs and fins to aid locomotion. Many of these appendages are not actively controlled, instead they have to interact passively with the surrounding fluid to generate motion. Here, we use theory, experiments and numerical simulations to show that an object with a protrusion in a separated flow drifts sideways by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in a fluid flow is unstable and how it stabilizes either to the left or right of the incoming flow direction. It is plausible that organisms with appendages in a separated flow use this newly discovered mechanism for locomotion; examples include the drift of plumed seeds without wind and the passive reorientation of motile animals. PMID:25354545

Passive damping concepts for tubular beams with partial rotational and translational end restraints

NASA Technical Reports Server (NTRS)

Razzaq, Zia; Muyundo, David K.

1991-01-01

The main objectives of the study are: (1) identification of potential passive damping concepts for slender tubular structural members with rotational and translational end springs under natural and forced-free vibrations; (2) evaluation of damping efficiencies of the various damping concepts; and (3) evaluation of the suitability of a theoretical finite difference analysis by comparison to the experimental results for the case of natural vibrations. Only member flexural an translation motion is considered. The natural vibration study is conducted on the seven damping concepts and for only one specific initial deflection. The most suitable of the seven dampers is further investigated under forced-free vibrations. In addition only one set of end springs is used for all of the experiments. The results show that passive damping provides a possible approach to structural vibration reduction.

The intertarsal joint of the ostrich (Struthio camelus): Anatomical examination and function of passive structures in locomotion

PubMed Central

Schaller, Nina U; Herkner, Bernd; Villa, Rikk; Aerts, Peter

2009-01-01

The ostrich (Struthio camelus) is the largest extant biped. Being flightless, it exhibits advanced cursorial abilities primarily evident in its characteristic speed and endurance. In addition to the active musculoskeletal complex, its powerful pelvic limbs incorporate passive structures wherein ligaments interact with joint surfaces, cartilage and other connective tissue in their course of motion. This arrangement may enable energy conservation by providing joint stabilisation, optimised limb segment orientation and automated positioning of ground contact elements independently of direct muscle control. The intertarsal joint is of particular interest considering its position near the mid-point of the extended limb and its exposure to high load during stance with significant inertial forces during swing phase. Functional-anatomical analysis of the dissected isolated joint describes the interaction of ligaments with intertarsal joint contours through the full motion cycle. Manual manipulation identified a passive engage-disengage mechanism (EDM) that establishes joint extension, provides bi-directional resistance prior to a transition point located at 115° and contributes to rapid intertarsal flexion at toe off and full extension prior to touch down. This effect was subsequently quantified by measurement of intertarsal joint moments in prepared anatomical specimens in a neutral horizontal position and axially-loaded vertical position. Correlation with kinematic analyses of walking and running ostriches confirms the contribution of the EDM in vivo. We hypothesise that the passive EDM operates in tandem with a stringently coupled multi-jointed muscle-tendon system to conserve the metabolic cost of locomotion in the ostrich, suggesting that a complete understanding of terrestrial locomotion across extinct and extant taxa must include functional consideration of the ligamentous system. PMID:19538629

Descriptive profile of hip range of motion in elite tennis players.

PubMed

Moreno-Pérez, Victor; Ayala, Francisco; Fernandez-Fernandez, Jaime; Vera-Garcia, Francisco J

2016-05-01

To describe the range of motion (ROM) profile (flexion, extension, abduction, internal and external rotation) of the hip in elite tennis players; and (b) to analyse if there are sex-related differences in the hip ROM. Cohort study. Controlled laboratory environment. 81 male and 28 female tennis players completed this study. Descriptive measures of passive hip flexion, extension and abduction, and internal and external active and passive hip rotation ROM were taken. Magnitude-based inferences on differences between sex (males vs. females) and hip (dominant vs. non-dominant) were made by standardising differences. No clinically meaningful bilateral and sex-related differences in any of the hip ROM measures. In addition, it was found that both males and females had restricted mobility measures on hip flexion (<80°), extension (<0°) and abduction (<40°). Furthermore, the 30% of males also presented restricted active and passive hip internal rotation ROM values (<25°). Finally, both males and females had normal mobility measures of hip external rotation ROM (active [>25°] and passive [35°]) Asymmetric hip joint ROM measures found during clinical examination and screening may indicate abnormalities and the need of rehabilitation (e.g., flexibility training). In addition, clinicians should include specific exercises (e.g., stretching) in their conditioning, prevention and rehabilitation programmes aiming to avoid restricted mobility of hip flexion (males = 74°; females = 78°), extension (males = -1.5; females = -0.4), abduction (males = 35°; females = 34°) and internal rotation (males = 30°; females = 35) that might be generated as a consequence of playing tennis. Copyright © 2015 Elsevier Ltd. All rights reserved.

77 FR 12906 - Notice of Release From Federal Grant Assurance Obligations at Fresno Yosemite International...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-02

... continue to use the land as passive wetlands, which will keep the property vacant and compatible with the... generating potential. The planned land use is for water recharge, ponding basin, and passive wetlands. The property will be kept mitigated to ensure that its passive use does not interfere with airport operations...

Multi-body dynamic coupling mechanism for generating throwing arm velocity during baseball pitching.

PubMed

Naito, Kozo; Takagi, Tokio; Kubota, Hideaki; Maruyama, Takeo

2017-08-01

The purpose of this study was to identify the detailed mechanism how the maximum throwing arm endpoint velocity is determined by the muscular torques and non-muscular interactive torques from the perspective of the dynamic coupling among the trunk, thorax and throwing and non-throwing arm segments. The pitching movements of ten male collegiate baseball pitchers were measured by a three-dimensional motion capture system. Using the induced-segmental velocity analysis (IVA) developed in this study, the maximum fingertip velocity of the throwing arm (MFV) was decomposed into each contribution of the muscular torques, passive motion-dependent torques due to gyroscopic moment, Coriolis force and centrifugal force, and other interactive torque components. The results showed that MFV (31.6±1.7m/s) was mainly attributed to two different mechanisms. The first is the passive motion-dependent effect on increasing the angular velocities of three joints (thorax rotation, elbow extension and wrist flexion). The second is the muscular torque effect of the shoulder internal rotation (IR) torque on generating IR angular velocity. In particular, the centrifugal force-induced elbow extension motion, which was the greatest contributor among individual joint contributions, was caused primarily by the angular velocity-dependent forces associated with the humerus, thorax, and trunk rotations. Our study also found that a compensatory mechanism was achieved by the negative and positive contributions of the muscular torque components. The current IVA is helpful to understand how the rapid throwing arm movement is determined by the dynamic coupling mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

iHandRehab: an interactive hand exoskeleton for active and passive rehabilitation.

PubMed

Li, Jiting; Zheng, Ruoyin; Zhang, Yuru; Yao, Jianchu

2011-01-01

This paper presents an interactive exoskeleton device for hand rehabilitation, iHandRehab, which aims to satisfy the essential requirements for both active and passive rehabilitation motions. iHandRehab is comprised of exoskeletons for the thumb and index finger. These exoskeletons are driven by distant actuation modules through a cable/sheath transmission mechanism. The exoskeleton for each finger has 4 degrees of freedom (DOF), providing independent control for all finger joints. The joint motion is accomplished by a parallelogram mechanism so that the joints of the device and their corresponding finger joints have the same angular displacement when they rotate. Thanks to this design, the joint angles can be measured by sensors real time and high level motion control is therefore made very simple without the need of complicated kinematics. The paper also discusses important issues when the device is used by different patients, including its adjustable joint range of motion (ROM) and adjustable range of phalanx length (ROPL). Experimentally collected data show that the achieved ROM is close to that of a healthy hand and the ROPL covers the size of a typical hand, satisfying the size need of regular hand rehabilitation. In order to evaluate the performance when it works as a haptic device in active mode, the equivalent moment of inertia (MOI) of the device is calculated. The results prove that the device has low inertia which is critical in order to obtain good backdrivability. Experimental analysis shows that the influence of friction accounts for a large portion of the driving torque and warrants future investigation. © 2011 IEEE

Time-resolved microrheology of actively remodeling actomyosin networks

NASA Astrophysics Data System (ADS)

Silva, Marina Soares e.; Stuhrmann, Björn; Betz, Timo; Koenderink, Gijsje H.

2014-07-01

Living cells constitute an extraordinary state of matter since they are inherently out of thermal equilibrium due to internal metabolic processes. Indeed, measurements of particle motion in the cytoplasm of animal cells have revealed clear signatures of nonthermal fluctuations superposed on passive thermal motion. However, it has been difficult to pinpoint the exact molecular origin of this activity. Here, we employ time-resolved microrheology based on particle tracking to measure nonequilibrium fluctuations produced by myosin motor proteins in a minimal model system composed of purified actin filaments and myosin motors. We show that the motors generate spatially heterogeneous contractile fluctuations, which become less frequent with time as a consequence of motor-driven network remodeling. We analyze the particle tracking data on different length scales, combining particle image velocimetry, an ensemble analysis of the particle trajectories, and finally a kymograph analysis of individual particle trajectories to quantify the length and time scales associated with active particle displacements. All analyses show clear signatures of nonequilibrium activity: the particles exhibit random motion with an enhanced amplitude compared to passive samples, and they exhibit sporadic contractile fluctuations with ballistic motion over large (up to 30 μm) distances. This nonequilibrium activity diminishes with sample age, even though the adenosine triphosphate level is held constant. We propose that network coarsening concentrates motors in large clusters and depletes them from the network, thus reducing the occurrence of contractile fluctuations. Our data provide valuable insight into the physical processes underlying stress generation within motor-driven actin networks and the analysis framework may prove useful for future microrheology studies in cells and model organisms.

Comparative Efficacy of Platelet Rich Plasma Injection, Corticosteroid Injection and Ultrasonic Therapy in the Treatment of Periarthritis Shoulder.

PubMed

Kothari, Shashank Yeshwant; Srikumar, Venkataraman; Singh, Neha

2017-05-01

Periarthritis (PA) shoulder characterised by pain and restricted range of motion has a plethora of treatment options with inconclusive evidence. Platelet Rich Plasma (PRP) is an emerging treatment option and its efficacy needs to be examined and compared with other routine interventions. To assess the efficacy of PRP injection and compare it with corticosteroid injection and ultrasonic therapy in the treatment of PA shoulder. Patients with PA shoulder (n=195) were randomised to receive single injection of PRP (2 ml) or corticosteroid (80 mg of methylprednisolone) or ultrasonic therapy (seven sittings in two weeks; 1.5 W/cm 2 , 1 MHz, continuous mode). All participants were also advised to perform a home based 10 minute exercise therapy. The primary outcome measure was active range of motion of the shoulder. Secondary outcome measures used were Visual Analogue Scale (VAS) for pain and a shortened version of Disabilities of the Arm, Shoulder and Hand (QuickDASH) for function. Participants were evaluated at 0, 3, 6 and 12 weeks. Chi-square test, one way and repeated measures of ANOVA tests were used to determine significant differences. PRP treatment resulted in statistically significant improvements over corticosteroid and ultrasonic therapy in active as well as passive range of motion of shoulder, VAS and QuickDASH at 12 weeks. At six weeks, PRP treatment resulted in statistically significant improvements over ultrasonic therapy in VAS and QuickDASH. No major adverse effects were observed. This study demonstrates that single injection of PRP is effective and better than corticosteroid injection or ultrasonic therapy in treatment of PA shoulder.

The ''self-stirred'' genome: Bulk and surface dynamics of the chromatin globule

NASA Astrophysics Data System (ADS)

Zidovska, Alexandra

Chromatin structure and dynamics control all aspects of DNA biology yet are poorly understood. In interphase, time between two cell divisions, chromatin fills the cell nucleus in its minimally condensed polymeric state. Chromatin serves as substrate to a number of biological processes, e.g. gene expression and DNA replication, which require it to become locally restructured. These are energy-consuming processes giving rise to non-equilibrium dynamics. Chromatin dynamics has been traditionally studied by imaging of fluorescently labeled nuclear proteins and single DNA-sites, thus focusing only on a small number of tracer particles. Recently, we developed an approach, displacement correlation spectroscopy (DCS) based on time-resolved image correlation analysis, to map chromatin dynamics simultaneously across the whole nucleus in cultured human cells. DCS revealed that chromatin movement was coherent across large regions (4-5 μm) for several seconds. Regions of coherent motion extended beyond the boundaries of single-chromosome territories, suggesting elastic coupling of motion over length scales much larger than those of genes. These large-scale, coupled motions were ATP-dependent and unidirectional for several seconds. Following these observations, we developed a hydrodynamic theory of active chromatin dynamics, using the two-fluid model and describing the content of cell nucleus as a chromatin solution, which is subject to both passive thermal fluctuations and active (ATP-consuming) scalar and vector events. In this work we continue in our efforts to elucidate the mechanism and function of the chromatin dynamics in interphase. We investigate the chromatin interactions with the nuclear envelope and compare the surface dynamics of the chromatin globule with its bulk dynamics.

Dynamic interactions of an integrated vehicle-electromagnetic energy harvester-tire system subject to uneven road excitations

NASA Astrophysics Data System (ADS)

Xing, Jing Tang; Sun, Zhe; Zhou, Sulian; Tan, Mingyi

2017-04-01

An investigation is undertaken of an integrated mechanical-electromagnetic coupling system consisting of a rigid vehicle with heave, roll, and pitch motions, four electromagnetic energy harvesters and four tires subject to uneven road excitations in order to improve the passengers' riding comfort and harvest the lost engine energy due to uneven roads. Following the derived mathematical formulations and the proposed solution approaches, the numerical simulations of this interaction system subject to a continuous sinusoidal road excitation and a single ramp impact are completed. The simulation results are presented as the dynamic response curves in the forms of the frequency spectrum and the time history, which reveals the complex interaction characteristics of the system for vibration reductions and energy harvesting performance. It has addressed the coupling effects on the dynamic characteristics of the integrated system caused by: (1) the natural modes and frequencies of the vehicle; (2) the vehicle rolling and pitching motions; (3) different road excitations on four wheels; (4) the time delay of a road ramp to impact both the front and rear wheels, etc., which cannot be tackled by an often used quarter vehicle model. The guidelines for engineering applications are given. The developed coupling model and the revealed concept provide a means with analysis idea to investigate the details of four energy harvester motions for electromagnetic suspension designs in order to replace the current passive vehicle isolators and to harvest the lost engine energy. Potential further research directions are suggested for readers to consider in the future.

Application of virtual reality graphics in assessment of concussion.

PubMed

Slobounov, Semyon; Slobounov, Elena; Newell, Karl

2006-04-01

Abnormal balance in individuals suffering from traumatic brain injury (TBI) has been documented in numerous recent studies. However, specific mechanisms causing balance deficits have not been systematically examined. This paper demonstrated the destabilizing effect of visual field motion, induced by virtual reality graphics in concussed individuals but not in normal controls. Fifty five student-athletes at risk for concussion participated in this study prior to injury and 10 of these subjects who suffered MTBI were tested again on day 3, day 10, and day 30 after the incident. Postural responses to visual field motion were recorded using a virtual reality (VR) environment in conjunction with balance (AMTI force plate) and motion tracking (Flock of Birds) technologies. Two experimental conditions were introduced where subjects passively viewed VR scenes or actively manipulated the visual field motion. Long-lasting destabilizing effects of visual field motion were revealed, although subjects were asymptomatic when standard balance tests were introduced. The findings demonstrate that advanced VR technology may detect residual symptoms of concussion at least 30 days post-injury.

Seismic passive earth resistance using modified pseudo-dynamic method

NASA Astrophysics Data System (ADS)

Pain, Anindya; Choudhury, Deepankar; Bhattacharyya, S. K.

2017-04-01

In earthquake prone areas, understanding of the seismic passive earth resistance is very important for the design of different geotechnical earth retaining structures. In this study, the limit equilibrium method is used for estimation of critical seismic passive earth resistance for an inclined wall supporting horizontal cohesionless backfill. A composite failure surface is considered in the present analysis. Seismic forces are computed assuming the backfill soil as a viscoelastic material overlying a rigid stratum and the rigid stratum is subjected to a harmonic shaking. The present method satisfies the boundary conditions. The amplification of acceleration depends on the properties of the backfill soil and on the characteristics of the input motion. The acceleration distribution along the depth of the backfill is found to be nonlinear in nature. The present study shows that the horizontal and vertical acceleration distribution in the backfill soil is not always in-phase for the critical value of the seismic passive earth pressure coefficient. The effect of different parameters on the seismic passive earth pressure is studied in detail. A comparison of the present method with other theories is also presented, which shows the merits of the present study.

A 6DOF passive vibration isolator using X-shape supporting structures

NASA Astrophysics Data System (ADS)

Wu, Zhijing; Jing, Xingjian; Sun, Bo; Li, Fengming

2016-10-01

A novel 6 degree of freedom (6-DOF) passive vibration isolator is studied theoretically and validated with experiments. Based on the Stewart platform configuration, the 6-DOF isolator is constructed by 6 X-shape structures as legs, which can realize very good and tunable vibration isolation performance in all 6 directions with a passive manner. The mechanic model is established for static analysis of the working range, static stiffness and loading capacity. Thereafter, the equation of motion of the isolator is derived with the Hamilton principle. The equivalent stiffness and the displacement transmissibility in the six decoupled DOFs direction are then discussed with experimental results for validation. The results reveal that (a) by designing the structure parameters, the system can possess flexible stiffness such as negative, quasi-zero and positive stiffness, (b) due to the combination of the Stewart platform and the X-shape structure, the system can have very good vibration isolation performance in all the 6 directions and in a passive manner, and (c) compared with the simplified linear-stiffness legs, the nonlinearity of the X-shape structures enhance the passive isolator to have much better vibration isolation performance.

Physiological motion modeling for organ-mounted robots.

PubMed

Wood, Nathan A; Schwartzman, David; Zenati, Marco A; Riviere, Cameron N

2017-12-01

Organ-mounted robots passively compensate heartbeat and respiratory motion. In model-guided procedures, this motion can be a significant source of information that can be used to aid in localization or to add dynamic information to static preoperative maps. Models for estimating periodic motion are proposed for both position and orientation. These models are then tested on animal data and optimal orders are identified. Finally, methods for online identification are demonstrated. Models using exponential coordinates and Euler-angle parameterizations are as accurate as models using quaternion representations, yet require a quarter fewer parameters. Models which incorporate more than four cardiac or three respiration harmonics are no more accurate. Finally, online methods estimate model parameters as accurately as offline methods within three respiration cycles. These methods provide a complete framework for accurately modelling the periodic deformation of points anywhere on the surface of the heart in a closed chest. Copyright © 2017 John Wiley & Sons, Ltd.

Energy transfer and motion synchronization between mechanical oscillators through microhydrodynamic coupling

NASA Astrophysics Data System (ADS)

Wan, Yu; Jin, Kai; Ahmad, Talha J.; Black, Michael J.; Xu, Zhiping

2017-03-01

Fluidic environment is encountered for mechanical components in many circumstances, which not only damps the oscillation but also modulates their dynamical behaviors through hydrodynamic interactions. In this study, we examine energy transfer and motion synchronization between two mechanical micro-oscillators by performing thermal lattice-Boltzmann simulations. The coefficient of inter-oscillator energy transfer is measured to quantify the strength of microhydrodynamic coupling, which depends on their distance and fluid properties such as density and viscosity. Synchronized motion of the oscillators is observed in the simulations for typical parameter sets in relevant applications, with the formation and loss of stable anti-phase synchronization controlled by the oscillating frequency, amplitude, and hydrodynamic coupling strength. The critical ranges of key parameters to assure efficient energy transfer or highly synchronized motion are predicted. These findings could be used to advise mechanical design of passive and active devices that operate in fluid.

The effect of attention loading on the inhibition of choice reaction time to visual motion by concurrent rotary motion

NASA Technical Reports Server (NTRS)

Looper, M.

1976-01-01

This study investigates the influence of attention loading on the established intersensory effects of passive bodily rotation on choice reaction time (RT) to visual motion. Subjects sat at the center of rotation in an enclosed rotating chamber and observed an oscilloscope on which were, in the center, a tracking display and, 10 deg left of center, a RT line. Three tracking tasks and a no-tracking control condition were presented to all subjects in combination with the RT task, which occurred with and without concurrent cab rotations. Choice RT to line motions was inhibited (probability less than .001) both when there was simultaneous vestibular stimulation and when there was a tracking task; response latencies lengthened progressively with increased similarity between the RT and tracking tasks. However, the attention conditions did not affect the intersensory effect; the significance of this for the nature of the sensory interaction is discussed.

Note: Development of a small maglev-type antirolling system.

PubMed

Park, Cheol Hoon; Park, Hee Chang; Cho, Han Wook; Moon, Seok Jun; Chung, Tae Young

2010-05-01

Various passive and/or active antirolling devices have been used for suppressing the rolling motion of ships in the ocean. In this study, a maglev-type active mass driver (AMD) is developed for controlling the rolling motion of a shiplike structure. No friction is generated during the motion of this maglev-type AMD, as the moving mass is floated by the magnetic levitation force and displaced by the propulsion force generated by the linear motor. For verifying the feasibility of the proposed method, a small AMD having a moving mass of approximately 4.0 kg is constructed and used in a small-scale model of a catamaran. This paper presents the detailed design procedures and obtained experimental results. Our results show that the developed maglev-type AMD has the potential for use in controlling the rolling motion of ships and other oceanographic vessels.

Motion sickness elicited by passive rotation in squirrel monkeys

NASA Technical Reports Server (NTRS)

Daunton, Nancy G.; Fox, Robert A.

1991-01-01

Current theory and recent evidence suggest that motion sickness occurs under conditions of sensory input in which the normal motor programs for producing eye, head, and body movements are not functionally effective, i.e. under conditions in which there are difficulties in maintaining posture and controlling eye movements. Conditions involving conflicting or inconsistent visual-vestibular (VV) stimulation should thus result in greater sickness rates since the existing motor programs do not produce effective control of eye-head-body movements under such conditions. It is felt that the relationship of postural control to motion sickness is an important one and one often overlooked. The results are reported which showed that when postural requirements were minimized by fully restraining squirrel monkeys during hypogravity parabolic flight, no animals became motion sick, but over 80 percent of the same 11 animals became sick if they were unrestrained and maintained control of their posture.

Beating-heart registration for organ-mounted robots.

PubMed

Wood, Nathan A; Schwartzman, David; Passineau, Michael J; Moraca, Robert J; Zenati, Marco A; Riviere, Cameron N

2018-03-06

Organ-mounted robots address the problem of beating-heart surgery by adhering to the heart, passively providing a platform that approaches zero relative motion. Because of the quasi-periodic deformation of the heart due to heartbeat and respiration, registration must address not only spatial registration but also temporal registration. Motion data were collected in the porcine model in vivo (N = 6). Fourier series models of heart motion were developed. By comparing registrations generated using an iterative closest-point approach at different phases of respiration, the phase corresponding to minimum registration distance is identified. The spatiotemporal registration technique presented here reduces registration error by an average of 4.2 mm over the 6 trials, in comparison with a more simplistic static registration that merely averages out the physiological motion. An empirical metric for spatiotemporal registration of organ-mounted robots is defined and demonstrated using data from animal models in vivo. Copyright © 2018 John Wiley & Sons, Ltd.

On the origin of the photocurrent of electrochemically passivated p-InP(100) photoelectrodes.

PubMed

Goryachev, Andrey; Gao, Lu; van Veldhoven, René P J; Haverkort, Jos E M; Hofmann, Jan P; Hensen, Emiel J M

2018-05-15

III-V semiconductors such as InP are highly efficient light absorbers for photoelectrochemical (PEC) water splitting devices. Yet, their cathodic stability is limited due to photocorrosion and the measured photocurrents do not necessarily originate from H2 evolution only. We evaluated the PEC stability and activation of model p-InP(100) photocathodes upon photoelectrochemical passivation (i.e. repeated surface oxidation/reduction). The electrode was subjected to a sequence of linear potential scans with or without intermittent passivation steps (repeated passivation and continuous reduction, respectively). The evolution of H2 and PH3 gases was monitored by online electrochemical mass spectrometry (OLEMS) and the Faradaic efficiencies of these processes were determined. Repeated passivation led to an increase of the photocurrent in 0.5 M H2SO4, while continuous reduction did not affect the photocurrent of p-InP(100). Neither H2 nor PH3 formation increased to the same extent as the photocurrent during the repeated passivation treatment. Surface analysis of the spent electrodes revealed substantial roughening of the electrode surface by repeated passivation, while continuous reduction left the surface unaltered. On the other hand, photocathodic conditioning performed in 0.5 M HCl led to the expected correlation between photocurrent increase and H2 formation. Ultimately, the H2 evolution rates of the photoelectrodes in H2SO4 and HCl are comparable. The much higher photocurrent in H2SO4 is due to competing side-reactions. The results emphasize the need for a detailed evaluation of the Faradaic efficiencies of all the involved processes using a chemical-specific technique like OLEMS. Photo-OLEMS can be beneficial in the study of photoelectrochemical reactions enabling the instantaneous detection of small amounts of reaction by-products.

Segmenting Continuous Motions with Hidden Semi-markov Models and Gaussian Processes

PubMed Central

Nakamura, Tomoaki; Nagai, Takayuki; Mochihashi, Daichi; Kobayashi, Ichiro; Asoh, Hideki; Kaneko, Masahide

2017-01-01

Humans divide perceived continuous information into segments to facilitate recognition. For example, humans can segment speech waves into recognizable morphemes. Analogously, continuous motions are segmented into recognizable unit actions. People can divide continuous information into segments without using explicit segment points. This capacity for unsupervised segmentation is also useful for robots, because it enables them to flexibly learn languages, gestures, and actions. In this paper, we propose a Gaussian process-hidden semi-Markov model (GP-HSMM) that can divide continuous time series data into segments in an unsupervised manner. Our proposed method consists of a generative model based on the hidden semi-Markov model (HSMM), the emission distributions of which are Gaussian processes (GPs). Continuous time series data is generated by connecting segments generated by the GP. Segmentation can be achieved by using forward filtering-backward sampling to estimate the model's parameters, including the lengths and classes of the segments. In an experiment using the CMU motion capture dataset, we tested GP-HSMM with motion capture data containing simple exercise motions; the results of this experiment showed that the proposed GP-HSMM was comparable with other methods. We also conducted an experiment using karate motion capture data, which is more complex than exercise motion capture data; in this experiment, the segmentation accuracy of GP-HSMM was 0.92, which outperformed other methods. PMID:29311889

FIELD METHOD COMPARISON BETWEEN PASSIVE AIR SAMPLERS AND CONTINUOUS MONITORS FOR VOLATILE ORGANIC COMPOUNDS AND NO2 IN EL PASO, TEXAS, USA

EPA Science Inventory

Passive sampling of gas-phase air toxics and criteria pollutants has become an attractive monitoring method in human exposure studies due to the relatively low sampling cost and ease of use. This study evaluates the performance of Model 3300 Ogawa(TM) Passive NO2 Samplers and 3...

Measurement of intervertebral motion using quantitative fluoroscopy: report of an international forum and proposal for use in the assessment of degenerative disc disease in the lumbar spine.

PubMed

Breen, Alan C; Teyhen, Deydre S; Mellor, Fiona E; Breen, Alexander C; Wong, Kris W N; Deitz, Adam

2012-01-01

Quantitative fluoroscopy (QF) is an emerging technology for measuring intervertebral motion patterns to investigate problem back pain and degenerative disc disease. This International Forum was a networking event of three research groups (UK, US, Hong Kong), over three days in San Francisco in August 2009. Its aim was to reach a consensus on how best to record, analyse, and communicate QF information for research and clinical purposes. The Forum recommended that images should be acquired during regular trunk motion that is controlled for velocity and range, in order to minimise externally imposed variability as well as to correlate intervertebral motion with trunk motion. This should be done in both the recumbent passive and weight bearing active patient configurations. The main recommended outputs from QF were the true ranges of intervertebral rotation and translation, neutral zone laxity and the consistency of shape of the motion patterns. The main clinical research priority should initially be to investigate the possibility of mechanical subgroups of patients with chronic, nonspecific low back pain by comparing their intervertebral motion patterns with those of matched healthy controls.

Design and Validation of Exoskeleton Actuated by Soft Modules toward Neurorehabilitation-Vision-Based Control for Precise Reaching Motion of Upper Limb.

PubMed

Oguntosin, Victoria W; Mori, Yoshiki; Kim, Hyejong; Nasuto, Slawomir J; Kawamura, Sadao; Hayashi, Yoshikatsu

2017-01-01

We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM). Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realized by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable, wearable, and portable systems are required to be customized for individuals with specific motor impairments.

Design and Validation of Exoskeleton Actuated by Soft Modules toward Neurorehabilitation—Vision-Based Control for Precise Reaching Motion of Upper Limb

PubMed Central

Oguntosin, Victoria W.; Mori, Yoshiki; Kim, Hyejong; Nasuto, Slawomir J.; Kawamura, Sadao; Hayashi, Yoshikatsu

2017-01-01

We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM). Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realized by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable, wearable, and portable systems are required to be customized for individuals with specific motor impairments. PMID:28736514

Space/Time Statistics of Polar Ice Motion

NASA Technical Reports Server (NTRS)

Emery, William J.; Fowler, Charles; Maslanik, James A.

2003-01-01

Ice motions have been computed from passive microwave imagery (SMMR and SSM/I) on a daily basis for both Polar Regions. In the Arctic these daily motions have been merged with daily motions from AVHRR imagery and the Arctic buoy program. In the Antarctic motion only from the AVHRR were available for merging with the passive microwave vectors. Long-term means, monthly means and weekly means have all been computed from the resulting 22-year time series of polar ice motion. Papers are in preparation that present the long term (22 year) means, their variability and show animations of the monthly means over this time period for both Polar Regions. These papers will have links to "enhanced objects" that allow the reader to view the animations as part of the paper. The first paper presents the ice motion results from each of the Polar Regions. The second paper looks only at ice motion in the Arctic in order to develop a time series of ice age in the Arctic. Starting with the first full SMMR year in 1979 we keep track of each individual "ice element" (resolution of the sensor) and track it in the subsequent monthly time series. After a year we "age" each "particle" and we thus can keep track of the age of the ice starting in 1979. We keep track of ice age classes between one and five years and thus we can see the evolution of the ice as it ages after the initial 5-year period. This calculation shows how we are losing the older ice through Fram Strait at a rather alarming rate particularly in the past 15 years. This loss of older ice has resulted in an overall decrease in the thickest, oldest ice, which is now limited to a region just north of the Canadian Archipelago with tongues extending out across the pole towards the Siberian Shelf. This loss of old ice is consistent with the effects of global warming which provides the heat needed to melt, move and disperse this oldest ice through Fram Strait. This is the first step in a progression that may eventually open the Arctic ice pack and lead to an ice-free Arctic Ocean.

Patellar fixation protected with a load-sharing cable: a mechanical and clinical study.

PubMed

Perry, C R; McCarthy, J A; Kain, C C; Pearson, R L

1988-01-01

The stability of patellar fracture fixation protected with a load-sharing cable was studied in cadavers. A transverse patellar osteotomy was produced and stabilized with standard patellar fixation with or without a figure-of-eight cable that extends from the proximal pole of the patella to the tibial tubercle. Standard fixation techniques (interfragmentary cancellous screws or modified tension-band wiring) alone failed after significantly fewer cycles of flexion and extension than did the same fixation when supplemented with a load-sharing cable. In the clinical evaluation of the load-sharing cable, 14 consecutive patients with displaced patellar fractures were treated. No immobilization was used and the patients were started on passive and active range of motion and weight-bearing ambulation in the early postoperative period. Thirteen fractures healed uneventfully. The increased stability of patellar fracture fixation protected with a load-sharing cable offers three advantages: (a) adjunctive casting is unnecessary, (b) comminuted fractures can be "pieced" together anatomically with less concern for loss of fixation, and (c) early postoperative passive and active range of motion can be achieved.

Classification of resistance to passive motion using minimum probability of error criterion.

PubMed

Chan, H C; Manry, M T; Kondraske, G V

1987-01-01

Neurologists diagnose many muscular and nerve disorders by classifying the resistance to passive motion of patients' limbs. Over the past several years, a computer-based instrument has been developed for automated measurement and parameterization of this resistance. In the device, a voluntarily relaxed lower extremity is moved at constant velocity by a motorized driver. The torque exerted on the extremity by the machine is sampled, along with the angle of the extremity. In this paper a computerized technique is described for classifying a patient's condition as 'Normal' or 'Parkinson disease' (rigidity), from the torque versus angle curve for the knee joint. A Legendre polynomial, fit to the curve, is used to calculate a set of eight normally distributed features of the curve. The minimum probability of error approach is used to classify the curve as being from a normal or Parkinson disease patient. Data collected from 44 different subjects was processes and the results were compared with an independent physician's subjective assessment of rigidity. There is agreement in better than 95% of the cases, when all of the features are used.

A habituation based approach for detection of visual changes in surveillance camera

NASA Astrophysics Data System (ADS)

Sha'abani, M. N. A. H.; Adan, N. F.; Sabani, M. S. M.; Abdullah, F.; Nadira, J. H. S.; Yasin, M. S. M.

2017-09-01

This paper investigates a habituation based approach in detecting visual changes using video surveillance systems in a passive environment. Various techniques have been introduced for dynamic environment such as motion detection, object classification and behaviour analysis. However, in a passive environment, most of the scenes recorded by the surveillance system are normal. Therefore, implementing a complex analysis all the time in the passive environment resulting on computationally expensive, especially when using a high video resolution. Thus, a mechanism of attention is required, where the system only responds to an abnormal event. This paper proposed a novelty detection mechanism in detecting visual changes and a habituation based approach to measure the level of novelty. The objective of the paper is to investigate the feasibility of the habituation based approach in detecting visual changes. Experiment results show that the approach are able to accurately detect the presence of novelty as deviations from the learned knowledge.

Kinematic Effects of Nickel-Titanium Instruments with Reciprocating or Continuous Rotation Motion: A Systematic Review of In Vitro Studies.

PubMed

Ahn, So-Yeon; Kim, Hyeon-Cheol; Kim, Euiseong

2016-07-01

This review aimed to compare the kinematic effect of nickel-titanium instruments with reciprocating and continuous rotation motion for cyclic fatigue resistance, shaping ability, apical debris extrusion, and dentinal defects or cracks. Articles were selected for inclusion in this review if they fulfilled all of the following criteria: described in vitro studies performed on either extracted human teeth or an artificial canal model, assessed both reciprocating and rotary instruments, compared reciprocating files and rotary files for the kinematics of files, and evaluated reciprocating and rotary files regarding the aim of this study. The electronic search was undertaken in MEDLINE, Cochrane database, and manual searches, including journals, reference lists, and other reviews. Twelve studies were chosen for cyclic fatigue, 19 studies for shaping ability, 14 studies for apical debris extrusion, and 13 studies for dentinal defects or cracks. Most of the studies showed that reciprocating motion had a higher resistance to cyclic fatigue. Nine studies from the shaping studies reported less canal transportation by using the reciprocating motion than the continuous rotation. The reciprocating instruments tended to extrude more dentin debris than the continuous rotating instruments, but many of the studies showed conflicting results. In addition, 2 studies from the defects or cracks studies claimed the reciprocating motion produced more dentinal defects than the continuous rotating motion. Instruments with reciprocating motion seemed to have better resistance to cyclic fatigue with less canal transportation tendency than the instruments with continuous rotating motion. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Folding in and out: passive morphing in flapping wings.

PubMed

Stowers, Amanda K; Lentink, David

2015-03-25

We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover within a beat.

Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

PubMed

Andrade, R J; Freitas, S R; Vaz, J R; Bruno, P M; Pezarat-Correia, P

2015-06-01

This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P < 0.05). Upper trunk positioning had an effect on the knee submaximal torque (P < 0.05), observed as an increase in the knee passive submaximal torque when the cervical and thoracic spines were flexed (P < 0.05). In conclusion, other apparently mechanical unrelated body segments influence torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Altered transfer of visual motion information to parietal association cortex in untreated first-episode psychosis: Implications for pursuit eye tracking

PubMed Central

Lencer, Rebekka; Keedy, Sarah K.; Reilly, James L.; McDonough, Bruce E.; Harris, Margret S. H.; Sprenger, Andreas; Sweeney, John A.

2011-01-01

Visual motion processing and its use for pursuit eye movement control represent a valuable model for studying the use of sensory input for action planning. In psychotic disorders, alterations of visual motion perception have been suggested to cause pursuit eye tracking deficits. We evaluated this system in functional neuroimaging studies of untreated first-episode schizophrenia (N=24), psychotic bipolar disorder patients (N=13) and healthy controls (N=20). During a passive visual motion processing task, both patient groups showed reduced activation in the posterior parietal projection fields of motion-sensitive extrastriate area V5, but not in V5 itself. This suggests reduced bottom-up transfer of visual motion information from extrastriate cortex to perceptual systems in parietal association cortex. During active pursuit, activation was enhanced in anterior intraparietal sulcus and insula in both patient groups, and in dorsolateral prefrontal cortex and dorsomedial thalamus in schizophrenia patients. This may result from increased demands on sensorimotor systems for pursuit control due to the limited availability of perceptual motion information about target speed and tracking error. Visual motion information transfer deficits to higher -level association cortex may contribute to well-established pursuit tracking abnormalities, and perhaps to a wider array of alterations in perception and action planning in psychotic disorders. PMID:21873035

Real-Time Motion Tracking for Mobile Augmented/Virtual Reality Using Adaptive Visual-Inertial Fusion

PubMed Central

Fang, Wei; Zheng, Lianyu; Deng, Huanjun; Zhang, Hongbo

2017-01-01

In mobile augmented/virtual reality (AR/VR), real-time 6-Degree of Freedom (DoF) motion tracking is essential for the registration between virtual scenes and the real world. However, due to the limited computational capacity of mobile terminals today, the latency between consecutive arriving poses would damage the user experience in mobile AR/VR. Thus, a visual-inertial based real-time motion tracking for mobile AR/VR is proposed in this paper. By means of high frequency and passive outputs from the inertial sensor, the real-time performance of arriving poses for mobile AR/VR is achieved. In addition, to alleviate the jitter phenomenon during the visual-inertial fusion, an adaptive filter framework is established to cope with different motion situations automatically, enabling the real-time 6-DoF motion tracking by balancing the jitter and latency. Besides, the robustness of the traditional visual-only based motion tracking is enhanced, giving rise to a better mobile AR/VR performance when motion blur is encountered. Finally, experiments are carried out to demonstrate the proposed method, and the results show that this work is capable of providing a smooth and robust 6-DoF motion tracking for mobile AR/VR in real-time. PMID:28475145

Use of cues in virtual reality depends on visual feedback.

PubMed

Fulvio, Jacqueline M; Rokers, Bas

2017-11-22

3D motion perception is of central importance to daily life. However, when tested in laboratory settings, sensitivity to 3D motion signals is found to be poor, leading to the view that heuristics and prior assumptions are critical for 3D motion perception. Here we explore an alternative: sensitivity to 3D motion signals is context-dependent and must be learned based on explicit visual feedback in novel environments. The need for action-contingent visual feedback is well-established in the developmental literature. For example, young kittens that are passively moved through an environment, but unable to move through it themselves, fail to develop accurate depth perception. We find that these principles also obtain in adult human perception. Observers that do not experience visual consequences of their actions fail to develop accurate 3D motion perception in a virtual reality environment, even after prolonged exposure. By contrast, observers that experience the consequences of their actions improve performance based on available sensory cues to 3D motion. Specifically, we find that observers learn to exploit the small motion parallax cues provided by head jitter. Our findings advance understanding of human 3D motion processing and form a foundation for future study of perception in virtual and natural 3D environments.

Real-Time Motion Tracking for Mobile Augmented/Virtual Reality Using Adaptive Visual-Inertial Fusion.

PubMed

Fang, Wei; Zheng, Lianyu; Deng, Huanjun; Zhang, Hongbo

2017-05-05

In mobile augmented/virtual reality (AR/VR), real-time 6-Degree of Freedom (DoF) motion tracking is essential for the registration between virtual scenes and the real world. However, due to the limited computational capacity of mobile terminals today, the latency between consecutive arriving poses would damage the user experience in mobile AR/VR. Thus, a visual-inertial based real-time motion tracking for mobile AR/VR is proposed in this paper. By means of high frequency and passive outputs from the inertial sensor, the real-time performance of arriving poses for mobile AR/VR is achieved. In addition, to alleviate the jitter phenomenon during the visual-inertial fusion, an adaptive filter framework is established to cope with different motion situations automatically, enabling the real-time 6-DoF motion tracking by balancing the jitter and latency. Besides, the robustness of the traditional visual-only based motion tracking is enhanced, giving rise to a better mobile AR/VR performance when motion blur is encountered. Finally, experiments are carried out to demonstrate the proposed method, and the results show that this work is capable of providing a smooth and robust 6-DoF motion tracking for mobile AR/VR in real-time.

Biomechanical performance of baseball pitchers with a history of ulnar collateral ligament reconstruction.

PubMed

Fleisig, Glenn S; Leddon, Charles E; Laughlin, Walter A; Ciccotti, Michael G; Mandelbaum, Bert R; Aune, Kyle T; Escamilla, Rafael F; MacLeod, Toran D; Andrews, James R

2015-05-01

A relatively high number of active professional baseball pitchers have a history of ulnar collateral ligament reconstruction (UCLr) on their throwing elbow. Controversy exists in the literature about whether professional baseball pitchers regain optimal performance after return from UCLr. It has been suggested that pitchers may have different biomechanics after UCLr, but this has not been previously tested. It was hypothesized that, compared with a control group without a history of UCLr, professional pitchers with a history of UCLr would have (1) significantly different throwing elbow and shoulder biomechanics; (2) a shortened stride, insufficient trunk forward tilt, and excessive shoulder horizontal adduction, characteristics associated with "holding back" or being tentative; (3) late shoulder rotation; and (4) improper shoulder abduction and trunk lateral tilt. Controlled laboratory study. A total of 80 active minor league baseball pitchers (and their 8 Major League Baseball organizations) agreed to participate in this study. Participants included 40 pitchers with a history of UCLr and a matched control group of 40 pitchers with no history of elbow or shoulder surgery. Passive ranges of motion were measured for each pitcher's elbows and shoulders, and then 23 reflective markers were attached to his body. The pitcher took as many warm-up pitches as desired and then threw 10 full-effort fastballs for data collection. Ball speed was recorded with a radar gun. The reflective markers were tracked with a 10-camera, 240-Hz automated motion analysis system. Eleven biomechanical parameters were computed for each pitch and then averaged for each participant. Demographic, range of motion, and biomechanical parameters were compared between the UCLr group and the control group by use of Student t tests (significance set at P<.05). All hypotheses were rejected, as there were no differences in pitching biomechanics between the UCLr group and the control group. There were also no differences in passive range of motion between the 2 groups. Compared with a control group, active professional pitchers with a history of UCLr displayed no significant differences in shoulder and elbow passive range of motion and no significant differences in elbow and shoulder biomechanics. Clinical studies have previously shown that 10% to 33% of professional pitchers do not return to their preinjury level; however, the current study showed that those pitchers who successfully return to professional baseball after UCLr pitch with biomechanics similar to that of noninjured professionals. © 2015 The Author(s).

CFD simulation of a 2 bladed multi megawatt wind turbine with flexible rotor connection

NASA Astrophysics Data System (ADS)

Klein, L.; Luhmann, B.; Rösch, K.-N.; Lutz, T.; Cheng, P.-W.; Krämer, E.

2016-09-01

An innovative passive load reduction concept for a two bladed 3.4 MW wind turbine is investigated by a conjoint CFD and MBS - BEM methodology. The concept consists of a flexible hub mount which allows a tumbling motion of the rotor. First, the system is simulated with a MBS tool coupled to a BEM code. Then, the resulting motion of the rotor is extracted from the simulation and applied on the CFD simulation as prescribed motion. The aerodynamic results show a significant load reduction on the support structure. Hub pitching and yawing moment amplitudes are reduced by more than 50% in a vertically sheared inflow. Furthermore, the suitability of the MBS - BEM approach for the simulation of the load reduction system is shown.

Cooling the center-of-mass motion of a diamond nanocrystal in a magneto-gravitational trap

NASA Astrophysics Data System (ADS)

Hsu, Jen-Feng

A magneto-gravitational trap for micro/nanometer sized diamagnetic particles, such as diamond nanocrystals, is tested and characterized. After exploring various other systems, such as a suspended graphene beam and an optical trap, this magneto-gravitational nanomechanical trapping system for diamond with nitrogen-vacancy (NV) centers presents unique advantages for experiments in fundamental quantum mechanics. Those include, for example, the generation of large quantum superposition states and tests of quantum gravity. Features are demonstrated for this system, such as stable and passive levitation from atmospheric pressure to high vacuum, low resonant frequencies and damping rates, and cooling of the center-of-mass motions to below 1 K. The construction of the trap, vacuum system, optics, and motion detection electronics are described in detail.

Motion onset does not capture attention when subsequent motion is "smooth".

PubMed

Sunny, Meera Mary; von Mühlenen, Adrian

2011-12-01

Previous research on the attentional effects of moving objects has shown that motion per se does not capture attention. However, in later studies it was argued that the onset of motion does capture attention. Here, we show that this motion-onset effect critically depends on motion jerkiness--that is, the rate at which the moving stimulus is refreshed. Experiment 1 used search displays with a static, a motion-onset, and an abrupt-onset stimulus, while systematically varying the refresh rate of the moving stimulus. The results showed that motion onset only captures attention when subsequent motion is jerky (8 and 17 Hz), not when it is smooth (33 and 100 Hz). Experiment 2 replaced motion onset with continuous motion, showing that motion jerkiness does not affect how continuous motion is processed. These findings do not support accounts that assume a special role for motion onset, but they are in line with the more general unique-event account.

Biomechanical analysis of INFINITY rehabilitation method for treatment of low back pain

PubMed Central

Daniel, Matej; Tomanová, Michaela; Hornová, Jana; Novotná, Iva; Lhotská, Lenka

2017-01-01

[Purpose] Low back pain is a pervasive problem in modern societies. Physical rehabilitation in treatment of low back pain should reduce pain, muscle tension and restore spine stability and balance. The INFINITY® rehabilitation method that is based on a figure of eight movement pattern was proved to be effective in low back pain treatment. The aim of the paper is to estimate the effect of a figure of eight motion on the L5/S1 load and lumbar spine muscle activation in comparison to other motion patterns. [Subjects and Methods] Three-dimensional model of lumbar spine musculoskeletal system is used to simulate effect of various load motion pattern induced by displacement of the center of gravity of the upper body. Four motion patterns were examined: lateral and oblique pendulum-like motion, elliptical motion and figure of eight motion. [Results] The simple pendulum-like and elliptical-like patterns induce harmonic muscle activation and harmonic spinal load. The figure of eight motion pattern creates high-frequency spinal loading that activates remodeling of bones and tendons. The figure of eight pattern also requires muscle activity that differs from harmonic frequency and is more demanding on muscle control and could also improve muscle coordination. [Conclusion] The results of the study indicate that complex motion pattern during INFINITY® rehabilitation might enhance the spine stability by influencing its passive, active and neural components. PMID:28603355

Local collective motion analysis for multi-probe dynamic imaging and microrheology

NASA Astrophysics Data System (ADS)

Khan, Manas; Mason, Thomas G.

2016-08-01

Dynamical artifacts, such as mechanical drift, advection, and hydrodynamic flow, can adversely affect multi-probe dynamic imaging and passive particle-tracking microrheology experiments. Alternatively, active driving by molecular motors can cause interesting non-Brownian motion of probes in local regions. Existing drift-correction techniques, which require large ensembles of probes or fast temporal sampling, are inadequate for handling complex spatio-temporal drifts and non-Brownian motion of localized domains containing relatively few probes. Here, we report an analytical method based on local collective motion (LCM) analysis of as few as two probes for detecting the presence of non-Brownian motion and for accurately eliminating it to reveal the underlying Brownian motion. By calculating an ensemble-average, time-dependent, LCM mean square displacement (MSD) of two or more localized probes and comparing this MSD to constituent single-probe MSDs, we can identify temporal regimes during which either thermal or athermal motion dominates. Single-probe motion, when referenced relative to the moving frame attached to the multi-probe LCM trajectory, provides a true Brownian MSD after scaling by an appropriate correction factor that depends on the number of probes used in LCM analysis. We show that LCM analysis can be used to correct many different dynamical artifacts, including spatially varying drifts, gradient flows, cell motion, time-dependent drift, and temporally varying oscillatory advection, thereby offering a significant improvement over existing approaches.

Passive monitoring using traffic noise recordings - case study on the Steinachtal Bridge

NASA Astrophysics Data System (ADS)

Salvermoser, Johannes; Stähler, Simon; Hadziioannou, Céline

2015-04-01

Civil structures age continuously. The early recognition of potentially critical damages is an important economical issue, but also one of public safety. Continuous tracking of small changes in the medium by using passive methods would offer an extension to established active non-destructive testing procedures at relatively low cost. Here we present a case study of structural monitoring using continuous recordings of traffic noise on a 200 meter long reinforced concrete highway bridge in Germany. Over two months of continuos geophone records are used in the frequency range of 2-8 Hz. Using passive image interferometry, evaluation of hourly cross-correlations between recordings at pairs of receivers yield velocity variations in the range of -1.5% to +2.1%. We were able to correlate our outcomes with temperature measurements of the same two month period. The measured velocity changes scale with the temperature variations with on average a dv/v of 0.064% per degree Celsius. This value is in accordance with other studies of concrete response to temperature, confirming that we are able to observe subtle changes with physical origin. It is shown that traffic noise is temporally homogenenous enough to fulfill the requirements of passive image interferometry.

Effect of gradual weight-bearing on regenerated articular cartilage after joint distraction and motion in a rabbit model.

PubMed

Nishino, Tomofumi; Ishii, Tomoo; Chang, Fei; Yanai, Takaji; Watanabe, Arata; Ogawa, Takeshi; Mishima, Hajime; Nakai, Kenjiro; Ochiai, Naoyuki

2010-05-01

The purpose of this study was to clarify the effect of gradual weight bearing (GWB) on regenerating cartilage. We developed a novel external fixation device (EFD) with a controllable weight-bearing system and continuous passive motion (CPM). A full-thickness defect was created by resection of the entire articular surface of the tibial plateau after the EFD was fixed in the rabbit's left knee. In the GWB group (n=6), GWB was started 6 weeks after surgery. In the CPM group (n=6), CPM with EFD was applied in the same manner without GWB. The control group (n=5) received only joint distraction. All rabbits were sacrificed 9 weeks after surgery. The central one-third of the regenerated tissue was assessed and scored blindly using a grading scale modified from the International Cartilage Repair Society visual histological assessment scale. The areas stained by Safranin-O and type II collagen antibody were measured, and the percentage of each area was calculated. There was no significant difference in the histological assessment scale among the groups. The percentage of the type II collagen-positive area was significantly larger in the GWB group than in the CPM group. The present study suggests that optimal mechanical stress, such as GWB, may affect regeneration of cartilage, in vivo. Copyright (c) 2009 Orthopaedic Research Society.

Polymer optics for the passive infrared

NASA Astrophysics Data System (ADS)

Claytor, Richard N.

2016-10-01

An important, but largely invisible, area of polymer optics involves sensing the motion of warm objects. It can be further subdivided into optics for security, for energy conservation, and for convenience; the area has become known as optics for the passive infrared. The passive infrared is generally known as the 8 to 14 μm region of the optical spectrum. The region's roots are in the traditional infrared technology of many decades ago; there is a coincident atmospheric window, although that has little relevance to many short-range applications relevant to polymer optics. Regrettably, there is no polymer material ideally suited to the passive infrared, but one material is generally superior to other candidates. The inadequacy of this material makes the Fresnel lens important. Polymer optics for the passive infrared were first introduced in the 1970s. Patents from that period will be shown, as well as early examples. The unfamiliar names of the pioneering companies and their technical leaders will be mentioned. The 1980s and 90s brought a new and improved lens type, and rapid growth. Pigments for visible-light appearance and other reasons were introduced; one was a spectacular failure. Recent advances include faster lenses, a new groove structure, additional pigments, and lens-mirror combinations. New sensor types are also being introduced. Finally, some unique and inventive applications will be discussed.

Anticipatory eye movements evoked after active following versus passive observation of a predictable motion stimulus.

PubMed

Burke, M R; Barnes, G R

2008-12-15

We used passive and active following of a predictable smooth pursuit stimulus in order to establish if predictive eye movement responses are equivalent under both passive and active conditions. The smooth pursuit stimulus was presented in pairs that were either 'predictable' in which both presentations were matched in timing and velocity, or 'randomized' in which each presentation in the pair was varied in both timing and velocity. A visual cue signaled the type of response required from the subject; a green cue indicated the subject should follow both the target presentations (Go-Go), a pink cue indicated that the subject should passively observe the 1st target and follow the 2nd target (NoGo-Go), and finally a green cue with a black cross revealed a randomized (Rnd) trial in which the subject should follow both presentations. The results revealed better prediction in the Go-Go trials than in the NoGo-Go trials, as indicated by higher anticipatory velocity and earlier eye movement onset (latency). We conclude that velocity and timing information stored from passive observation of a moving target is diminished when compared to active following of the target. This study has significant consequences for understanding how visuomotor memory is generated, stored and subsequently released from short-term memory.

The effect of glenosphere diameter in reverse shoulder arthroplasty on muscle force, joint load, and range of motion.

PubMed

Langohr, G Daniel G; Giles, Joshua W; Athwal, George S; Johnson, James A

2015-06-01

Little is known about the effects of glenosphere diameter on shoulder joint loads. The purpose of this biomechanical study was to investigate the effects of glenosphere diameter on joint load, load angle, and total deltoid force required for active abduction and range of motion in internal/external rotation and abduction. A custom, instrumented reverse shoulder arthroplasty implant system capable of measuring joint load and varying glenosphere diameter (38 and 42 mm) and glenoid offset (neutral and lateral) was implanted in 6 cadaveric shoulders to provide at least 80% power for all variables. A shoulder motion simulator was used to produce active glenohumeral and scapulothoracic motion. All implant configurations were tested with active and passive motion with joint kinematics, loads, and moments recorded. At neutral and lateralized glenosphere positions, increasing diameter significantly increased joint load (+12 ± 21 N and +6 ± 9 N; P < .01) and deltoid load required for active abduction (+9 ± 22 N and +11 ± 15 N; P < .02), whereas joint load angle was unaffected (P > .8). Passive internal rotation was reduced with increased diameter at both neutral and lateralized glenosphere positions (-6° ± 6° and -12° ± 6°; P < .002); however, external rotation was not affected (P > .05). At neutral glenosphere position, increasing diameter increased the maximum angles of both adduction (+1° ± 1°; P = .03) and abduction (+8° ± 9°; P < .05). Lateralization also increased abduction range of motion compared with neutral (P < .01). Although increasing glenosphere diameter significantly increased joint load and deltoid force, the clinical impact of these changes is presently unclear. Internal rotation, however, was reduced, which contradicts previous bone modeling studies, which we postulate is due to increased posterior capsular tension as it is forced to wrap around a larger 42 mm implant assembly. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Instrumentation techniques for monitoring shock and detonation waves

NASA Astrophysics Data System (ADS)

Dick, R. D.; Parrish, R. L.

1985-09-01

CORRTEX (Continuous Reflectometry for Radius Versus Time Experiments), SLIFER (Shorted Location Indication by Frequency of Electrical Resonance), and pin probes were used to monitor several conditions of blasting such as the detonation velocity of the explosive, the functioning of the stemming column confining the explosive, and rock mass motion. CORRTEX is a passive device that employs time-domain reflectometry to interrogate the two-way transit time of a coaxial cable. SLIFER is an active device that monitors the changing frequency resulting from a change in length of a coaxial cable forming an element of an oscillator circuit. Pin probes in this application consist of RG-174 coaxial cables, each with an open circuit, placed at several known locations within the material. Each cable is connected to a pulse-forming network and a voltage source. When the cables are shorted by the advancing wave, time-distance data are produced from which a velocity can be computed. Each technique, installation of the gauge, examples of the signals, and interpretation of the records are described.

Expanding research capabilities with sea ice climate records for analysis of long-term climate change and short-term variability

NASA Astrophysics Data System (ADS)

Scott, D. J.; Meier, W. N.

2008-12-01

Recent sea ice analysis is leading to predictions of a sea ice-free summertime in the Arctic within 20 years, or even sooner. Sea ice topics, such as concentration, extent, motion, and age, are predominately studied using satellite data. At the National Snow and Ice Data Center (NSIDC), passive microwave sea ice data sets provide timely assessments of seasonal-scale variability as well as consistent long-term climate data records. Such data sets are crucial to understanding changes and assessing their impacts. Noticeable impacts of changing sea ice conditions on native cultures and wildlife in the Arctic region are now being documented. With continued deterioration in Arctic sea ice, global economic impacts will be seen as new shipping routes open. NSIDC is at the forefront of making climate data records available to address the changes in sea ice and its global impacts. By focusing on integrated data sets, NSIDC leads the way by broadening the studies of sea ice beyond the traditional cryospheric community.

Controlled in-situ dissolution of an alkali metal

DOEpatents

Jones, Jeffrey Donald; Dooley, Kirk John; Tolman, David Donald

2012-09-11

A method for the controllable dissolution of one or more alkali metals from a vessel containing a one or more alkali metals and/or one or more partially passivated alkali metals. The vessel preferably comprising a sodium, NaK or other alkali metal-cooled nuclear reactor that has been used. The alkali metal, preferably sodium, potassium or a combination thereof, in the vessel is exposed to a treatment liquid, preferably an acidic liquid, more preferably citric acid. Preferably, the treatment liquid is maintained in continuous motion relative to any surface of unreacted alkali metal with which the treatment liquid is in contact. The treatment liquid is preferably pumped into the vessel containing the one or more alkali metals and the resulting fluid is extracted and optionally further processed. Preferably, the resulting off-gases are processed by an off-gas treatment system and the resulting liquids are processed by a liquid disposal system. In one preferred embodiment, an inert gas is pumped into the vessel along with the treatment liquid.

Forward flight of swallowtail butterfly with simple flapping motion.

PubMed

Tanaka, Hiroto; Shimoyama, Isao

2010-06-01

Unlike other flying insects, the wing motion of swallowtail butterflies is basically limited to flapping because their fore wings partly overlap their hind wings, structurally restricting the feathering needed for active control of aerodynamic force. Hence, it can be hypothesized that the flight of swallowtail butterflies is realized with simple flapping, requiring little feedback control of the feathering angle. To verify this hypothesis, we fabricated an artificial butterfly mimicking the wing motion and wing shape of a swallowtail butterfly and analyzed its flights using images taken with a high-speed video camera. The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion. During the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping, and the artificial butterfly followed an undulating flight trajectory like an actual swallowtail butterfly. Without feedback control of the wing motion, the body movement is directly affected by change of aerodynamic force due to the wing deformation; the degree of deformation was determined by the wing venation. Unlike a veinless wing, a mimic wing with veins generated a much higher lift coefficient during the flapping flight than in a steady flow due to the large body motion.

Sensing and Force-Feedback Exoskeleton (SAFE) Robotic Glove.

PubMed

Ben-Tzvi, Pinhas; Ma, Zhou

2015-11-01

This paper presents the design, implementation and experimental validation of a novel robotic haptic exoskeleton device to measure the user's hand motion and assist hand motion while remaining portable and lightweight. The device consists of a five-finger mechanism actuated with miniature DC motors through antagonistically routed cables at each finger, which act as both active and passive force actuators. The SAFE Glove is a wireless and self-contained mechatronic system that mounts over the dorsum of a bare hand and provides haptic force feedback to each finger. The glove is adaptable to a wide variety of finger sizes without constraining the range of motion. This makes it possible to accurately and comfortably track the complex motion of the finger and thumb joints associated with common movements of hand functions, including grip and release patterns. The glove can be wirelessly linked to a computer for displaying and recording the hand status through 3D Graphical User Interface (GUI) in real-time. The experimental results demonstrate that the SAFE Glove is capable of reliably modeling hand kinematics, measuring finger motion and assisting hand grasping motion. Simulation and experimental results show the potential of the proposed system in rehabilitation therapy and virtual reality applications.

Reynolds number scaling of straining motions in turbulence

NASA Astrophysics Data System (ADS)

Elsinga, Gerrit; Ishihara, T.; Goudar, M. V.; da Silva, C. B.; Hunt, J. C. R.

2017-11-01

Strain is an important fluid motion in turbulence as it is associated with the kinetic energy dissipation rate, vorticity stretching, and the dispersion of passive scalars. The present study investigates the scaling of the turbulent straining motions by evaluating the flow in the eigenframe of the local strain-rate tensor. The analysis is based on DNS of homogeneous isotropic turbulence covering a Reynolds number range Reλ = 34.6 - 1131. The resulting flow pattern reveals a shear layer containing tube-like vortices and a dissipation sheet, which both scale on the Kolmogorov length scale, η. The vorticity stretching motions scale on the Taylor length scale, while the flow outside the shear layer scales on the integral length scale. These scaling results are consistent with those in wall-bounded flow, which suggests a quantitative universality between the different flows. The overall coherence length of the vorticity is 120 η in all directions, which is considerably larger than the typical size of individual vortices, and reflects the importance of spatial organization at the small scales. Transitions in flow structure are identified at Reλ 45 and 250. Below these respective Reynolds numbers, the small-scale motions and the vorticity stretching motions appear underdeveloped.

A Novel, Nonoperative Treatment Demonstrates Success for Stiff Total Knee Arthroplasty after Failure of Conventional Therapy.

PubMed

Chughtai, Morad; Mont, Michael A; Cherian, Chris; Cherian, Jeffrey Jai; Elmallah, Randa D K; Naziri, Qais; Harwin, Steven F; Bhave, Anil

2016-04-01

Certain patients continue to suffer from knee stiffness following total knee arthroplasty (TKA) despite undergoing conventional therapies. Astym therapy to these patients may offer an effective, safe, nonoperative treatment. This study evaluates the effects of Astym therapy upon (1) range of motion and (2) subjective functional improvements in post-TKA patients who suffered from stiffness recalcitrant to other nonoperative interventions. Twenty-three post-TKA patients (29 knees) who had recalcitrant knee stiffness were included in this study. Pre- and post-Astym improvements in range of motion and Knee Society scores were compared. We analyzed knees based on the presence of flexion deficit or contracture. Further stratification was made into knees that received Astym therapy before and after a 3-month period of standard rehabilitation. Differences in range of motion from pre- to post-Astym were evaluated by measuring (1) degree of flexion deficit or contracture and (2) total arc of passive motion. Improvements in subjective functional status were determined by evaluating Knee Society scores pre- and post-Astym therapy. A two-tailed Student t-test was used to compare weighted mean differences from pre- to post-Astym for the above parameters. The mean flexion deficit improved significantly (p < 0.001) in all patients after Astym therapy. The mean flexion contracture improved significantly in (p = 0.001) in 91% of patients after Astym therapy. Knees with flexion deficits or contractures both improved in total arc of motion when compared with pretherapy. Overall, patients who underwent treatment with Astym therapy reported significant mean improvements in both Knee Society objective (80 vs. 57 points; p < 0.0001) and functional scores (80 vs. 54 points; p = 0.0003) when compared with their pretherapy objective and functional scores. No harms were reported. Astym therapy is a novel, nonoperative treatment that may be an effective treatment option for post-TKA patients suffering from persistent knee stiffness. Further studies are needed to validate this intervention as a part of cost-effective, standard treatment after TKA. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Effect of passive polarizing three-dimensional displays on surgical performance for experienced laparoscopic surgeons.

PubMed

Smith, R; Schwab, K; Day, A; Rockall, T; Ballard, K; Bailey, M; Jourdan, I

2014-10-01

Although the potential benefits of stereoscopic laparoscopy have been recognized for years, the technology has not been adopted because of poor operator tolerance. Passive polarizing projection systems, which have revolutionized three-dimensional (3D) cinema, are now being trialled in surgery. This study was designed to see whether this technology resulted in significant performance benefits for skilled laparoscopists. Four validated laparoscopic skills tasks, each with ten repetitions, were performed by 20 experienced laparoscopic surgeons, in both two-dimensional (2D) and 3D conditions. The primary outcome measure was the performance error rate; secondary outcome measures were time for task completion, 3D motion tracking (path length, motion smoothness and grasping frequency) and workload dimension ratings of the National Aeronautics and Space Administration (NASA) Task Load Index. Surgeons demonstrated a 62 per cent reduction in the median number of errors and a 35 per cent reduction in median performance time when using the passive polarizing 3D display compared with the 2D display. There was a significant 15 per cent reduction in median instrument path length, an enhancement of median motion smoothness, and a 15 per cent decrease in grasper frequency with the 3D display. Participants reported significant reductions in subjective workload dimension ratings of the NASA Task Load Index following use of the 3D displays. Passive polarizing 3D displays improved both the performance of experienced surgeons in a simulated setting and surgeon perception of the operative field. Although it has been argued that the experience of skilled laparoscopic surgeons compensates fully for the loss of stereopsis, this study indicates that this is not the case. Surgical relevance The potential benefits of stereoscopic laparoscopy have been known for years, but the technology has not been adopted because of poor operator tolerance. The first laparoscopic operation was carried out using a prototype passive polarizing laparoscopic system in 2010. This is new three-dimensional (3D) technology offers a real option for 3D laparoscopic surgery where previous systems have failed. This study is the first to have been carried out using this technology. It is essential that new technologies are adopted only when there is robust evidence to support their use. Currently, there are concerns about the use of robotic technologies and whether advantages exist for patient care. If there are advantages, 3D must be playing a significant role. If so, perhaps the technology under investigation here offers potential to a greater spectrum of surgeons, as well as being a more affordable option. © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.

Deficits in glenohumeral passive range of motion increase risk of elbow injury in professional baseball pitchers: a prospective study.

PubMed

Wilk, Kevin E; Macrina, Leonard C; Fleisig, Glenn S; Aune, Kyle T; Porterfield, Ron A; Harker, Paul; Evans, Timothy J; Andrews, James R

2014-09-01

Injuries to the elbow joint in baseball pitchers appear common. There appears to be a correlation between shoulder range of motion and elbow injuries. To prospectively determine whether decreased ROM of the throwing shoulder is correlated with the onset of elbow injuries in professional baseball pitchers. Cohort study; Level of evidence, 2. For 8 consecutive years (2005-2012), passive range of motion of both the throwing and nonthrowing shoulders of all major and minor league pitchers within a single professional baseball organization were measured by using a bubble goniometer during spring training. In total, 505 examinations were conducted on 296 pitchers. Glenohumeral external rotation and internal rotation were assessed in the supine position with the arm at 90° of abduction and in the plane of the scapula. The scapula was stabilized per methods previously established. Total rotation was defined as the sum of external rotation and internal rotation. Passive shoulder flexion was assessed with the subject supine and the scapula stabilized per methods previously established. Elbow injuries and days missed because of elbow injuries were assessed and recorded by the medical staff of the team. Throwing and nonthrowing shoulder measurements were compared by using Student t tests; 1-tailed Fisher exact tests were performed to identify significant associations between shoulder motion and elbow injury. Nominal logistic regression was performed to determine the odds of elbow injury. Significant differences were noted during side-to-side comparisons within subjects. There were 49 elbow injuries and 8 surgeries in 38 players, accounting for a total of 2551 days missed. Neither glenohumeral internal rotation deficit nor external rotation insufficiency was correlated with elbow injuries. Pitchers with deficits of >5° in total rotation in their throwing shoulders had a 2.6 times greater risk for injury. Pitchers with deficit of ≥5° in flexion of the throwing shoulder had a 2.8 times greater risk for injury. Bilateral differences in shoulder total rotation and flexion had a significant effect on the risk for elbow injuries in pitchers. Clinicians need to be aware of these findings and plan preventive programs that address these issues in hopes of reducing elbow injuries. © 2014 The Author(s).

Implant preloading in extension reduces spring length change in dynamic intraligamentary stabilization: a biomechanical study on passive kinematics of the knee.

PubMed

Häberli, Janosch; Voumard, Benjamin; Kösters, Clemens; Delfosse, Daniel; Henle, Philipp; Eggli, Stefan; Zysset, Philippe

2018-06-01

Dynamic intraligamentary stabilization (DIS) is a primary repair technique for acute anterior cruciate ligament (ACL) tears. For internal bracing of the sutured ACL, a metal spring with 8 mm maximum length change is preloaded with 60-80 N and fixed to a high-strength polyethylene braid. The bulky tibial hardware results in bone loss and may cause local discomfort with the necessity of hardware removal. The technique has been previously investigated biomechanically; however, the amount of spring shortening during movement of the knee joint is unknown. Spring shortening is a crucial measure, because it defines the necessary dimensions of the spring and, therefore, the overall size of the implant. Seven Thiel-fixated human cadaveric knee joints were subjected to passive range of motion (flexion/extension, internal/external rotation in 90° flexion, and varus/valgus stress in 0° and 20° flexion) and stability tests (Lachman/KT-1000 testing in 0°, 15°, 30°, 60°, and 90° flexion) in the ACL-intact, ACL-transected, and DIS-repaired state. Kinematic data of femur, tibia, and implant spring were recorded with an optical measurement system (Optotrak) and the positions of the bone tunnels were assessed by computed tomography. Length change of bone tunnel distance as a surrogate for spring shortening was then computed from kinematic data. Tunnel positioning in a circular zone with r = 5 mm was simulated to account for surgical precision and its influence on length change was assessed. Over all range of motion and stability tests, spring shortening was highest (5.0 ± 0.2 mm) during varus stress in 0° knee flexion. During flexion/extension, spring shortening was always highest in full extension (3.8 ± 0.3 mm) for all specimens and all simulations of bone tunnels. Tunnel distance shortening was highest (0.15 mm/°) for posterior femoral and posterior tibial tunnel positioning and lowest (0.03 mm/°) for anterior femoral and anterior tibial tunnel positioning. During passive flexion/extension, the highest spring shortening was consistently measured in full extension with a continuous decrease towards flexion. If preloading of the spring is performed in extension, the spring can be downsized to incorporate a maximum length change of 5 mm resulting in a smaller implant with less bone sacrifice and, therefore, improved conditions in case of revision surgery.

A continuous-wave and passively Q-switched Nd:LaGGG laser at 937 nm

NASA Astrophysics Data System (ADS)

Li, Z.-Y.; Ying, H.-Y.; Yang, H.; He, J.-L.

2013-10-01

A diode-end-pumped continuous-wave (CW) and passively Q-switched Nd:LaGGG (GGG: gadolinium gallium garnet) laser at about 937 nm was demonstrated for the first time. The maximum CW output power of 540 mW was obtained with the optical-optical conversion efficiency of 3.2% and the slope efficiency of 4.4%. A V3+:YAG (yttrium aluminum garnet) saturable absorber with the initial transmission of 97% was used for the passive Q-switching regime. The shortest pulse width was achieved as 500 ns with the pulse repetition rate of 96 kHz. The corresponding single-pulse energy and pulse peak power were determined as 1.56 μJ and 3.12 W, respectively.

Techniques of ozone monitoring in a mountain forest region: passive and continuous sampling, vertical and canopy profiles.

PubMed

Gerosa, G; Mazzali, C; Ballarin-Denti, A

2001-10-31

Ozone is the most harmful air pollutant for plant ecosystems in the Mediterranean and Alpine areas due to its biological and economic damage to crops and forests. In order to evaluate the relation between ozone exposure and vegetation injury under on-field conditions, suitable ozone monitoring techniques were investigated. In the framework of a 5-year research project aimed at ozone risk assessment on forests, both continuous analysers and passive samplers were employed during the summer seasons (1994-1998) in different sites of a wide mountain region (80 x 40 km2) on the southern slope of the European Alps. Continuous analysers allowed the recording of ozone hourly concentration means necessary both to calculate specific exposure indexes (such as AOT, SUM, W126) and to record daily time-courses. Passive samplers, even though supplied only weekly mean concentration values, made it possible to estimate the altitude concentration gradient useful to correct the altitude dependence of ozone concentrations to be inserted into exposure indexes. In-canopy ozone profiles were also determined by placing passive samplers at different heights inside the forest canopy. Vertical ozone soundings by means of tethered balloons (kytoons) allowed the measurement of the vertical concentration gradient above the forest canopy. They also revealed ozone reservoirs aloft and were useful to explain the ozone advection dynamic in mountain slopes where ground measurement proved to be inadequate. An intercomparison between passive (PASSAM, CH) and continuous measurements highlighted the necessity to accurately standardize all the exposure operations, particularly the pre- and postexposure conservation at cold temperature to avoid dye (DPE) activity. Advantages and disadvantages from each mentioned technique are discussed.

Comparative Efficacy of Platelet Rich Plasma Injection, Corticosteroid Injection and Ultrasonic Therapy in the Treatment of Periarthritis Shoulder

PubMed Central

Srikumar, Venkataraman; Singh, Neha

2017-01-01

Introduction Periarthritis (PA) shoulder characterised by pain and restricted range of motion has a plethora of treatment options with inconclusive evidence. Platelet Rich Plasma (PRP) is an emerging treatment option and its efficacy needs to be examined and compared with other routine interventions. Aim To assess the efficacy of PRP injection and compare it with corticosteroid injection and ultrasonic therapy in the treatment of PA shoulder. Materials and Methods Patients with PA shoulder (n=195) were randomised to receive single injection of PRP (2 ml) or corticosteroid (80 mg of methylprednisolone) or ultrasonic therapy (seven sittings in two weeks; 1.5 W/cm2, 1 MHz, continuous mode). All participants were also advised to perform a home based 10 minute exercise therapy. The primary outcome measure was active range of motion of the shoulder. Secondary outcome measures used were Visual Analogue Scale (VAS) for pain and a shortened version of Disabilities of the Arm, Shoulder and Hand (QuickDASH) for function. Participants were evaluated at 0, 3, 6 and 12 weeks. Chi-square test, one way and repeated measures of ANOVA tests were used to determine significant differences. Results PRP treatment resulted in statistically significant improvements over corticosteroid and ultrasonic therapy in active as well as passive range of motion of shoulder, VAS and QuickDASH at 12 weeks. At six weeks, PRP treatment resulted in statistically significant improvements over ultrasonic therapy in VAS and QuickDASH. No major adverse effects were observed. Conclusion This study demonstrates that single injection of PRP is effective and better than corticosteroid injection or ultrasonic therapy in treatment of PA shoulder. PMID:28658861

Clinical application of the Panjabi neutral zone hypothesis: the Stabilimax NZ posterior lumbar dynamic stabilization system.

PubMed

Yue, James J; Timm, Jens P; Panjabi, Manohar M; Jaramillo-de la Torre, Jorge

2007-01-15

The neutral zone (NZ) is a region of intervertebral motion around the neutral posture where little resistance is offered by the passive spinal column. The NZ appears to be a clinically important measure of spinal stability function. Its size may increase with injury to the spinal column, which in turn may result in spinal instability or low-back pain. Dynamic stabilization systems are designed to support and stabilize the spine while maintaining range of motion (ROM). The Stabilimax NZ device has been designed to reduce the NZ after spinal injury to treat pain while preserving ROM.

Stage separation study of Nike-Black Brant V Sounding Rocket System

NASA Technical Reports Server (NTRS)

Ferragut, N. J.

1976-01-01

A new Sounding Rocket System has been developed. It consists of a Nike Booster and a Black Brant V Sustainer with slanted fins which extend beyond its nozzle exit plane. A cursory look was taken at different factors which must be considered when studying a passive separation system. That is, one separation system without mechanical constraints in the axial direction and which will allow separation due to drag differential accelerations between the Booster and the Sustainer. The equations of motion were derived for rigid body motions and exact solutions were obtained. The analysis developed could be applied to any other staging problem of a Sounding Rocket System.

Automating arm movement training following severe stroke: functional exercises with quantitative feedback in a gravity-reduced environment.

PubMed

Sanchez, Robert J; Liu, Jiayin; Rao, Sandhya; Shah, Punit; Smith, Robert; Rahman, Tariq; Cramer, Steven C; Bobrow, James E; Reinkensmeyer, David J

2006-09-01

An important goal in rehabilitation engineering is to develop technology that allows individuals with severe motor impairment to practice arm movement without continuous supervision from a rehabilitation therapist. This paper describes the development of such a system, called Therapy WREX or ("T-WREX"). The system consists of an orthosis that assists in arm movement across a large workspace, a grip sensor that detects hand grip pressure, and software that simulates functional activities. The arm orthosis is an instrumented, adult-sized version of the Wilmington Robotic Exoskeleton (WREX), which is a five degrees-of-freedom mechanism that passively counterbalances the weight of the arm using elastic bands. After providing a detailed design description of T-WREX, this paper describes two pilot studies of the system's capabilities. The first study demonstrated that individuals with chronic stroke whose arm function is compromised in a normal gravity environment can perform reaching and drawing movements while using T-WREX. The second study demonstrated that exercising the affected arm of five people with chronic stroke with T-WREX over an eight week period improved unassisted movement ability (mean change in Fugl-Meyer score was 5 points +/- 2 SD; mean change in range of motion of reaching was 10%, p < 0.001). These results demonstrate the feasibility of automating upper-extremity rehabilitation therapy for people with severe stroke using passive gravity assistance, a grip sensor, and simple virtual reality software.

The role and position of passive intervertebral motion assessment within clinical reasoning and decision-making in manual physical therapy: a qualitative interview study.

PubMed

van Trijffel, Emiel; Plochg, Thomas; van Hartingsveld, Frank; Lucas, Cees; Oostendorp, Rob A B

2010-06-01

Passive intervertebral motion (PIVM) assessment is a characterizing skill of manual physical therapists (MPTs) and is important for judgments about impairments in spinal joint function. It is unknown as to why and how MPTs use this mobility testing of spinal motion segments within their clinical reasoning and decision-making. This qualitative study aimed to explore and understand the role and position of PIVM assessment within the manual diagnostic process. Eight semistructured individual interviews with expert MPTs and three subsequent group interviews using manual physical therapy consultation platforms were conducted. Line-by-line coding was performed on the transcribed data, and final main themes were identified from subcategories. Three researchers were involved in the analysis process. Four themes emerged from the data: contextuality, consistency, impairment orientedness, and subjectivity. These themes were interrelated and linked to concepts of professionalism and clinical reasoning. MPTs used PIVM assessment within a multidimensional, biopsychosocial framework incorporating clinical data relating to mechanical dysfunction as well as to personal factors while applying various clinical reasoning strategies. Interpretation of PIVM assessment and subsequent decisions on manipulative treatment were strongly rooted within practitioners' practical knowledge. This study has identified the specific role and position of PIVM assessment as related to other clinical findings within clinical reasoning and decision-making in manual physical therapy in The Netherlands. We recommend future research in manual diagnostics to account for the multivariable character of physical examination of the spine.

Vertebral bending mechanics and xenarthrous morphology in the nine-banded armadillo (Dasypus novemcinctus).

PubMed

Oliver, Jillian D; Jones, Katrina E; Hautier, Lionel; Loughry, W J; Pierce, Stephanie E

2016-10-01

The vertebral column has evolved to accommodate the broad range of locomotor pressures found across vertebrate lineages. Xenarthran (armadillos, sloths and anteaters) vertebral columns are characterized by xenarthrous articulations, novel intervertebral articulations located in the posterior trunk that are hypothesized to stiffen the vertebral column to facilitate digging. To determine the degree to which xenarthrous articulations impact vertebral movement, we passively measured compliance and range of motion during ventroflexion, dorsiflexion and lateral bending across the thoracolumbar region of the nine-banded armadillo, Dasypus novemcinctus Patterns of bending were compared with changes in vertebral morphology along the column to determine which morphological features best predict intervertebral joint mechanics. We found that compliance was lower in post-diaphragmatic, xenarthrous vertebrae relative to pre-xenarthrous vertebrae in both sagittal and lateral planes of bending. However, we also found that range of motion was higher in this region. These changes in mechanics are correlated with the transition from pre-xenarthrous to xenarthrous vertebrae, as well as with the transition from thoracic to lumbar vertebrae. Our results thus substantiate the hypothesis that xenarthrous articulations stiffen the vertebral column. Additionally, our data suggest that xenarthrous articulations, and their associated enlarged metapophyses, also act to increase the range of motion of the post-diaphragmatic region. We propose that xenarthrous articulations perform the dual role of stiffening the vertebral column and increasing mobility, resulting in passively stable vertebrae that are capable of substantial bending under appropriate loads. © 2016. Published by The Company of Biologists Ltd.

The role and position of passive intervertebral motion assessment within clinical reasoning and decision-making in manual physical therapy: a qualitative interview study

PubMed Central

van Trijffel, Emiel; Plochg, Thomas; van Hartingsveld, Frank; Lucas, Cees; Oostendorp, Rob A B

2010-01-01

Passive intervertebral motion (PIVM) assessment is a characterizing skill of manual physical therapists (MPTs) and is important for judgments about impairments in spinal joint function. It is unknown as to why and how MPTs use this mobility testing of spinal motion segments within their clinical reasoning and decision-making. This qualitative study aimed to explore and understand the role and position of PIVM assessment within the manual diagnostic process. Eight semistructured individual interviews with expert MPTs and three subsequent group interviews using manual physical therapy consultation platforms were conducted. Line-by-line coding was performed on the transcribed data, and final main themes were identified from subcategories. Three researchers were involved in the analysis process. Four themes emerged from the data: contextuality, consistency, impairment orientedness, and subjectivity. These themes were interrelated and linked to concepts of professionalism and clinical reasoning. MPTs used PIVM assessment within a multidimensional, biopsychosocial framework incorporating clinical data relating to mechanical dysfunction as well as to personal factors while applying various clinical reasoning strategies. Interpretation of PIVM assessment and subsequent decisions on manipulative treatment were strongly rooted within practitioners’ practical knowledge. This study has identified the specific role and position of PIVM assessment as related to other clinical findings within clinical reasoning and decision-making in manual physical therapy in The Netherlands. We recommend future research in manual diagnostics to account for the multivariable character of physical examination of the spine. PMID:21655394

Comparison of massage based on the tensegrity principle and classic massage in treating chronic shoulder pain.

PubMed

Kassolik, Krzysztof; Andrzejewski, Waldemar; Brzozowski, Marcin; Wilk, Iwona; Górecka-Midura, Lucyna; Ostrowska, Bożena; Krzyżanowski, Dominik; Kurpas, Donata

2013-09-01

The purpose of this study was to compare the clinical outcomes of classic massage to massage based on the tensegrity principle for patients with chronic idiopathic shoulder pain. Thirty subjects with chronic shoulder pain symptoms were divided into 2 groups, 15 subjects received classic (Swedish) massage to tissues surrounding the glenohumeral joint and 15 subjects received the massage using techniques based on the tensegrity principle. The tensegrity principle is based on directing treatment to the painful area and the tissues (muscles, fascia, and ligaments) that structurally support the painful area, thus treating tissues that have direct and indirect influence on the motion segment. Both treatment groups received 10 sessions over 2 weeks, each session lasted 20 minutes. The McGill Pain Questionnaire and glenohumeral ranges of motion were measured immediately before the first massage session, on the day the therapy ended 2 weeks after therapy started, and 1 month after the last massage. Subjects receiving massage based on the tensegrity principle demonstrated statistically significance improvement in the passive and active ranges of flexion and abduction of the glenohumeral joint. Pain decreased in both massage groups. This study showed increases in passive and active ranges of motion for flexion and abduction in patients who had massage based on the tensegrity principle. For pain outcomes, both classic and tensegrity massage groups demonstrated improvement. Copyright © 2013 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

Transient cardio-respiratory responses to visually induced tilt illusions

NASA Technical Reports Server (NTRS)

Wood, S. J.; Ramsdell, C. D.; Mullen, T. J.; Oman, C. M.; Harm, D. L.; Paloski, W. H.

2000-01-01

Although the orthostatic cardio-respiratory response is primarily mediated by the baroreflex, studies have shown that vestibular cues also contribute in both humans and animals. We have demonstrated a visually mediated response to illusory tilt in some human subjects. Blood pressure, heart and respiration rate, and lung volume were monitored in 16 supine human subjects during two types of visual stimulation, and compared with responses to real passive whole body tilt from supine to head 80 degrees upright. Visual tilt stimuli consisted of either a static scene from an overhead mirror or constant velocity scene motion along different body axes generated by an ultra-wide dome projection system. Visual vertical cues were initially aligned with the longitudinal body axis. Subjective tilt and self-motion were reported verbally. Although significant changes in cardio-respiratory parameters to illusory tilts could not be demonstrated for the entire group, several subjects showed significant transient decreases in mean blood pressure resembling their initial response to passive head-up tilt. Changes in pulse pressure and a slight elevation in heart rate were noted. These transient responses are consistent with the hypothesis that visual-vestibular input contributes to the initial cardiovascular adjustment to a change in posture in humans. On average the static scene elicited perceived tilt without rotation. Dome scene pitch and yaw elicited perceived tilt and rotation, and dome roll motion elicited perceived rotation without tilt. A significant correlation between the magnitude of physiological and subjective reports could not be demonstrated.

Tissue Motion and Assembly During Early Cardiovascular Morphogenesis

NASA Astrophysics Data System (ADS)

Rongish, Brenda

2010-03-01

Conventional dogma in the field of cardiovascular developmental biology suggests that cardiac precursor cells migrate to the embryonic midline to form a tubular heart. These progenitors are believed to move relative to their extracellular matrix (ECM); responding to stimulatory and inhibitory cues in their environment. The tubular heart that is formed by 30 hours post fertilization is comprised of two concentric layers: the muscular myocardium and the endothelial-like endocardium, which are separated by a thick layer of ECM believed to be secreted predominantly by the myocardial cells. Here we describe the origin and motility of fluorescently tagged endocardial precursors in transgenic (Tie1-YFP) quail embryos (R. Lansford, Caltech) using epifluorescence time-lapse imaging. To visualize the environment of migrating endocardial progenitors, we labeled two ECM components, fibronectin and fibrillin-2, via in vivo microinjection of fluorochrome-conjugated monoclonal antibodies. Dynamic imaging was performed at stages encompassing tubular heart assembly and early looping. We established the motion of endocardial precursor cells and presumptive cardiac ECM fibrils using both object tracking and particle image velocimetry (image cross correlation). We determined the relative importance of directed cell autonomous motility versus passive tissue movements in endocardial morphogenesis. The data show presumptive endocardial cells and cardiac ECM fibrils are swept passively into the anterior and posterior poles of the elongating tubular heart. These quantitative data indicate the contribution of cell autonomous motility displayed by endocardial precursors is limited. Thus, tissue motion drives most of the cell displacements during endocardial morphogenesis.

Assessment of the role of cross section on fatigue resistance of rotary files when used in reciprocation.

PubMed

Sekar, Vadhana; Kumar, Ranjith; Nandini, Suresh; Ballal, Suma; Velmurugan, Natanasabapathy

2016-01-01

The purpose of this study was to assess the role of cross section on cyclic fatigue resistance of One Shape, Revo-S SU, and Mtwo rotary files in continuous rotation and reciprocating motion in dynamic testing model. A total of 90 new rotary One Shape, Revo-S SU, and Mtwo files (ISO size 25, taper 0.06, length 25 mm) were subjected to continuous rotation or reciprocating motion. A cyclic fatigue testing device was fabricated with 60° angle of curvature and 5 mm radius. The dynamic testing of these files was performed using an electric motor which permitted the reproduction of pecking motion. All instruments were rotated or reciprocated until fracture occurred. The time taken for each instrument to fracture was recorded. All the fractured files were analyzed under a scanning electron microscope (SEM) to detect the mode of fracture. Statistical analysis was performed using one-way ANOVA, followed by Tukey's honestly significant difference post hoc test. The time taken for instruments in reciprocating motion to fail under cyclic loading was significantly longer when compared with groups in continuous rotary motion. There was a statistically significant difference between Mtwo rotary and the other two groups in both continuous and reciprocating motion. One Shape rotary files recorded significantly longer duration to fracture resistance when compared with Revo-S SU files in both continuous and reciprocating motion. SEM observations showed that the instruments of all groups had undergone a ductile mode of fracture. Reciprocating motion improved the cyclic fatigue resistance of all tested groups.

Assessment of the role of cross section on fatigue resistance of rotary files when used in reciprocation

PubMed Central

Sekar, Vadhana; Kumar, Ranjith; Nandini, Suresh; Ballal, Suma; Velmurugan, Natanasabapathy

2016-01-01

Objective: The purpose of this study was to assess the role of cross section on cyclic fatigue resistance of One Shape, Revo-S SU, and Mtwo rotary files in continuous rotation and reciprocating motion in dynamic testing model. Materials and Methods: A total of 90 new rotary One Shape, Revo-S SU, and Mtwo files (ISO size 25, taper 0.06, length 25 mm) were subjected to continuous rotation or reciprocating motion. A cyclic fatigue testing device was fabricated with 60° angle of curvature and 5 mm radius. The dynamic testing of these files was performed using an electric motor which permitted the reproduction of pecking motion. All instruments were rotated or reciprocated until fracture occurred. The time taken for each instrument to fracture was recorded. All the fractured files were analyzed under a scanning electron microscope (SEM) to detect the mode of fracture. Statistical analysis was performed using one-way ANOVA, followed by Tukey's honestly significant difference post hoc test. Results: The time taken for instruments in reciprocating motion to fail under cyclic loading was significantly longer when compared with groups in continuous rotary motion. There was a statistically significant difference between Mtwo rotary and the other two groups in both continuous and reciprocating motion. One Shape rotary files recorded significantly longer duration to fracture resistance when compared with Revo-S SU files in both continuous and reciprocating motion. SEM observations showed that the instruments of all groups had undergone a ductile mode of fracture. Conclusion: Reciprocating motion improved the cyclic fatigue resistance of all tested groups. PMID:28042272

General features of the retinal connectome determine the computation of motion anticipation

PubMed Central

Johnston, Jamie; Lagnado, Leon

2015-01-01

Motion anticipation allows the visual system to compensate for the slow speed of phototransduction so that a moving object can be accurately located. This correction is already present in the signal that ganglion cells send from the retina but the biophysical mechanisms underlying this computation are not known. Here we demonstrate that motion anticipation is computed autonomously within the dendritic tree of each ganglion cell and relies on feedforward inhibition. The passive and non-linear interaction of excitatory and inhibitory synapses enables the somatic voltage to encode the actual position of a moving object instead of its delayed representation. General rather than specific features of the retinal connectome govern this computation: an excess of inhibitory inputs over excitatory, with both being randomly distributed, allows tracking of all directions of motion, while the average distance between inputs determines the object velocities that can be compensated for. DOI: http://dx.doi.org/10.7554/eLife.06250.001 PMID:25786068

Whole-Body Human Inverse Dynamics with Distributed Micro-Accelerometers, Gyros and Force Sensing †

PubMed Central

Latella, Claudia; Kuppuswamy, Naveen; Romano, Francesco; Traversaro, Silvio; Nori, Francesco

2016-01-01

Human motion tracking is a powerful tool used in a large range of applications that require human movement analysis. Although it is a well-established technique, its main limitation is the lack of estimation of real-time kinetics information such as forces and torques during the motion capture. In this paper, we present a novel approach for a human soft wearable force tracking for the simultaneous estimation of whole-body forces along with the motion. The early stage of our framework encompasses traditional passive marker based methods, inertial and contact force sensor modalities and harnesses a probabilistic computational technique for estimating dynamic quantities, originally proposed in the domain of humanoid robot control. We present experimental analysis on subjects performing a two degrees-of-freedom bowing task, and we estimate the motion and kinetics quantities. The results demonstrate the validity of the proposed method. We discuss the possible use of this technique in the design of a novel soft wearable force tracking device and its potential applications. PMID:27213394

Intracellular microrheology of motile Amoeba proteus.

PubMed

Rogers, Salman S; Waigh, Thomas A; Lu, Jian R

2008-04-15

The motility of Amoeba proteus was examined using the technique of passive particle tracking microrheology, with the aid of newly developed particle tracking software, a fast digital camera, and an optical microscope. We tracked large numbers of endogeneous particles in the amoebae, which displayed subdiffusive motion at short timescales, corresponding to thermal motion in a viscoelastic medium, and superdiffusive motion at long timescales due to the convection of the cytoplasm. Subdiffusive motion was characterized by a rheological scaling exponent of 3/4 in the cortex, indicative of the semiflexible dynamics of the actin fibers. We observed shear-thinning in the flowing endoplasm, where exponents increased with increasing flow rate; i.e., the endoplasm became more fluid-like. The rheology of the cortex is found to be isotropic, reflecting an isotropic actin gel. A clear difference was seen between cortical and endoplasmic layers in terms of both viscoelasticity and flow velocity, where the profile of the latter is close to a Poiseuille flow for a Newtonian fluid.

Intracellular Microrheology of Motile Amoeba proteus

PubMed Central

Rogers, Salman S.; Waigh, Thomas A.; Lu, Jian R.

2008-01-01

The motility of Amoeba proteus was examined using the technique of passive particle tracking microrheology, with the aid of newly developed particle tracking software, a fast digital camera, and an optical microscope. We tracked large numbers of endogeneous particles in the amoebae, which displayed subdiffusive motion at short timescales, corresponding to thermal motion in a viscoelastic medium, and superdiffusive motion at long timescales due to the convection of the cytoplasm. Subdiffusive motion was characterized by a rheological scaling exponent of 3/4 in the cortex, indicative of the semiflexible dynamics of the actin fibers. We observed shear-thinning in the flowing endoplasm, where exponents increased with increasing flow rate; i.e., the endoplasm became more fluid-like. The rheology of the cortex is found to be isotropic, reflecting an isotropic actin gel. A clear difference was seen between cortical and endoplasmic layers in terms of both viscoelasticity and flow velocity, where the profile of the latter is close to a Poiseuille flow for a Newtonian fluid. PMID:18192370

Intracellular Microrheology of Motile Amoeba proteus

NASA Astrophysics Data System (ADS)

Rogers, S.; Waigh, T.; Lu, J.

2008-04-01

The motility of motile Amoeba proteus was examined using the technique of passive particle tracking microrheology, with the aid of newly-developed particle tracking software, a fast digital camera and an optical microscope. We tracked large numbers of endogeneous particles in the amoebae, which displayed subdiffusive motion at short time scales, corresponding to thermal motion in a viscoelastic medium, and superdiffusive motion at long time scales due to the convection of the cytoplasm. Subdiffusive motion was characterised by a rheological scaling exponent of 3/4 in the cortex, indicative of the semiflexible dynamics of the actin fibres. We observed shear-thinning in the flowing endoplasm, where exponents increased with increasing flow rate; i.e. the endoplasm became more fluid-like. The rheology of the cortex is found to be isotropic, reflecting an isotropic actin gel. A clear difference was seen between cortical and endoplasmic layers in terms of both viscoelasticity and flow velocity, where the profile of the latter is close to a Poiseuille flow for a Newtonian fluid.

Methods and apparatus to produce stick-slip motion of logging tool attached to a wireline drawn upward by a continuously rotating wireline drum

DOEpatents

Vail, III, William Banning; Momii, Steven Thomas

1998-01-01

Methods and apparatus are described to produce stick-slip motion of a logging tool within a cased well attached to a wireline that is drawn upward by a continuously rotating wireline drum. The stick-slip motion results in the periodic upward movement of the tool in the cased well described in terms of a dwell time during which time the tool is stationary, the move time during which time the tool moves, and the stroke that is upward distance that the tool translates during the "slip" portion of the stick-slip motion. This method of measurement is used to log the well at different vertical positions of the tool. Therefore, any typical "station-to-station logging tool" may be modified to be a "continuous logging tool", where "continuous" means that the wireline drum continually rotates while the tool undergoes stick-slip motion downhole and measurements are performed during the dwell times when the tool is momentarily stationary. The stick-slip methods of operation and the related apparatus are particularly described in terms of making measurements of formation resistivity from within a cased well during the dwell times when the tool is momentarily stationary during the periodic stick-slip motion of the logging tool.

Methods and apparatus to produce stick-slip motion of logging tool attached to a wireline drawn upward by a continuously rotating wireline drum

DOEpatents

Vail, W.B. III; Momii, S.T.

1998-02-10

Methods and apparatus are described to produce stick-slip motion of a logging tool within a cased well attached to a wireline that is drawn upward by a continuously rotating wireline drum. The stick-slip motion results in the periodic upward movement of the tool in the cased well described in terms of a dwell time during which time the tool is stationary, the move time during which time the tool moves, and the stroke that is upward distance that the tool translates during the ``slip`` portion of the stick-slip motion. This method of measurement is used to log the well at different vertical positions of the tool. Therefore, any typical ``station-to-station logging tool`` may be modified to be a ``continuous logging tool,`` where ``continuous`` means that the wireline drum continually rotates while the tool undergoes stick-slip motion downhole and measurements are performed during the dwell times when the tool is momentarily stationary. The stick-slip methods of operation and the related apparatus are particularly described in terms of making measurements of formation resistivity from within a cased well during the dwell times when the tool is momentarily stationary during the periodic stick-slip motion of the logging tool. 12 figs.

Stability of Dynamical Systems with Discontinuous Motions:

NASA Astrophysics Data System (ADS)

Michel, Anthony N.; Hou, Ling

In this paper we present a stability theory for discontinuous dynamical systems (DDS): continuous-time systems whose motions are not necessarily continuous with respect to time. We show that this theory is not only applicable in the analysis of DDS, but also in the analysis of continuous dynamical systems (continuous-time systems whose motions are continuous with respect to time), discrete-time dynamical systems (systems whose motions are defined at discrete points in time) and hybrid dynamical systems (HDS) (systems whose descriptions involve simultaneously continuous-time and discrete-time). We show that the stability results for DDS are in general less conservative than the corresponding well-known classical Lyapunov results for continuous dynamical systems and discrete-time dynamical systems. Although the DDS stability results are applicable to general dynamical systems defined on metric spaces (divorced from any kind of description by differential equations, or any other kinds of equations), we confine ourselves to finite-dimensional dynamical systems defined by ordinary differential equations and difference equations, to make this paper as widely accessible as possible. We present only sample results, namely, results for uniform asymptotic stability in the large.

Exploratory factor analysis for differentiating sensory and mechanical variables related to muscle-tendon unit elongation

PubMed Central

Chagas, Mauro H.; Magalhães, Fabrício A.; Peixoto, Gustavo H. C.; Pereira, Beatriz M.; Andrade, André G. P.; Menzel, Hans-Joachim K.

2016-01-01

ABSTRACT Background Stretching exercises are able to promote adaptations in the muscle-tendon unit (MTU), which can be tested through physiological and biomechanical variables. Identifying the key variables in MTU adaptations is crucial to improvements in training. Objective To perform an exploratory factor analysis (EFA) involving the variables often used to evaluate the response of the MTU to stretching exercises. Method Maximum joint range of motion (ROMMAX), ROM at first sensation of stretching (FSTROM), peak torque (torqueMAX), passive stiffness, normalized stiffness, passive energy, and normalized energy were investigated in 36 participants during passive knee extension on an isokinetic dynamometer. Stiffness and energy values were normalized by the muscle cross-sectional area and their passive mode assured by monitoring the EMG activity. Results EFA revealed two major factors that explained 89.68% of the total variance: 53.13% was explained by the variables torqueMAX, passive stiffness, normalized stiffness, passive energy, and normalized energy, whereas the remaining 36.55% was explained by the variables ROMMAX and FSTROM. Conclusion This result supports the literature wherein two main hypotheses (mechanical and sensory theories) have been suggested to describe the adaptations of the MTU to stretching exercises. Contrary to some studies, in the present investigation torqueMAX was significantly correlated with the variables of the mechanical theory rather than those of the sensory theory. Therefore, a new approach was proposed to explain the behavior of the torqueMAX during stretching exercises. PMID:27437715

Using Ozone To Clean and Passivate Oxygen-Handling Hardware

NASA Technical Reports Server (NTRS)

Torrance, Paul; Biesinger, Paul

2009-01-01

A proposed method of cleaning, passivating, and verifying the cleanliness of oxygen-handling hardware would extend the established art of cleaning by use of ozone. As used here, "cleaning" signifies ridding all exposed surfaces of combustible (in particular, carbon-based) contaminants. The method calls for exposing the surfaces of the hardware to ozone while monitoring the ozone effluent for carbon dioxide. The ozone would passivate the hardware while oxidizing carbon-based residues, converting the carbon in them to carbon dioxide. The exposure to ozone would be continued until no more carbon dioxide was detected, signifying that cleaning and passivation were complete.

A Preclinical Assessment of Early Continuous Passive Motion and Treadmill Therapeutic Exercises for Generating Chondroprotective Effects After Anterior Cruciate Ligament Rupture.

PubMed

Chang, Nai-Jen; Lee, Kuan-Wei; Chu, Chih-Jou; Shie, Ming-You; Chou, Pei-Hsi; Lin, Chih-Chan; Liang, Peir-In

2017-08-01

Anterior cruciate ligament (ACL) injury is a well-known risk factor for the development of posttraumatic osteoarthritis (PTOA). However, whether using continuous passive motion (CPM) with or without additional treadmill exercise (TRE) in early ACL injury might provide chondroprotective effects and further decrease the risk of PTOA has yet to be determined. CPM may offer an enhanced chondroprotective effect, but TRE may attenuate that effect due to the mechanical stress on the joint and inflammatory cytokines in the joint. Controlled laboratory study. Thirty adult New Zealand White male rabbits were randomly allocated to sedentary (SED), CPM, TRE, or CPM+TRE groups. Each rabbit underwent an ACL transection (ACLT) on the right knee, with the contralateral knee used as an internal control (sham). The 4 joint surfaces (ie, medial and lateral femoral condyles and tibial plateaus) were evaluated 4 weeks after surgery for gross appearance, histological characteristics, and quantitative osteoarthritis (OA) scores. Overall, at the end of testing, the CPM group experienced the best protective therapeutic effects in all compartments. In gross appearance, CPM resulted in normal articular surfaces, while the TRE and SED groups exhibited surface abrasion. Histological analysis showed significant differences in articular cartilage status. The CPM group had significantly better histological OA scores ( P < .01), corresponding to the smoothest cartilage surface and sound chondrocyte and collagen arrangement. This group also showed abundant glycosaminoglycan (GAG) content and a sound growth microenvironment, with significantly lower expression levels of the inflammatory cytokine tumor necrosis factor α and the apoptotic marker caspase 3. In contrast, the TRE and SED groups showed several features of damage: distinct graded cartilage abrasion; damaged collagen fibers, corresponding to noticeable collagen type X (osteoarthritic cartilage); reduced cartilage thickness; fewer cartilaginous cells; and the appearance of chondrocyte clusters. These groups also showed loss of GAG, corresponding to higher levels of inflammatory cytokines and apoptosis of articular chondrocytes. Furthermore, the CPM+TRE group displayed visible pathological changes in the superficial cartilage, indicating that early loading exercise may contribute to osteoarthritis. The sham treatment showed no difference in the changes in all compartments between groups. Immediate CPM therapy produces a superior in situ microenvironment for reducing the occurrence of PTOA after ACL injury without reconstruction in rabbits. These data suggest that immediate application of CPM therapy may be necessary to create a sound microenvironment in joints and possibly to decrease the risk of PTOA without or while awaiting ACL reconstruction. In contrast, both early active loading exercise and inactivity lead to the development of PTOA.

At Home Photography-Based Method for Measuring Wrist Range of Motion.

PubMed

Trehan, Samir K; Rancy, Schneider K; Johnsen, Parker H; Hillstrom, Howard J; Lee, Steve K; Wolfe, Scott W

2017-11-01

Purpose  To determine the reliability of wrist range of motion (WROM) measurements based on digital photographs taken by patients at home compared with traditional measurements done in the office with a goniometer. Methods  Sixty-nine postoperative patients were enrolled in this study at least 3 months postoperatively. Active and passive wrist flexion/extension and radial/ulnar deviation were recorded by one of the two attending surgeons with a 1-degree resolution goniometer at the last postoperative office visit. Patients were provided an illustrated instruction sheet detailing how to take digital photographic images at home in six wrist positions (active and passive flexion/extension, and radial/ulnar deviation). Wrist position was measured from digital images by both the attending surgeons in a randomized, blinded fashion on two separate occasions greater than 2 weeks apart using the same goniometer. Reliability analysis was performed using the intraclass correlation coefficient to assess agreement between clinical and photography-based goniometry, as well as intra- and interobserver agreement. Results  Out of 69 enrolled patients, 30 (43%) patients sent digital images. Of the 180 digital photographs, only 9 (5%) were missing or deemed inadequate for WROM measurements. Agreement between clinical and photography-based measurements was "almost perfect" for passive wrist flexion/extension and "substantial" for active wrist flexion/extension and radial/ulnar deviation. Inter- and intraobserver agreement for the attending surgeons was "almost perfect" for all measurements. Discussion  This study validates a photography-based goniometry protocol allowing accurate and reliable WROM measurements without direct physician contact. Passive WROM was more accurately measured from photographs than active WROM. This study builds on previous photography-based goniometry literature by validating a protocol in which patients or their families take and submit their own photographs. Clinical Relevance  Patient-performed photography-based goniometry represents an alternative to traditional clinical goniometry that could enable longer-term follow-up, overcome travel-related impediments to office visits, improve convenience, and reduce costs for patients.

Does joint line elevation after revision knee arthroplasty affect tibio-femoral kinematics, contact pressure or collateral ligament lengths? An in vitro analysis

PubMed Central

Kowalczewski, Jacek B.; Chevalier, Yan; Okon, Tomasz; Innocenti, Bernardo; Bellemans, Johan

2015-01-01

Introduction Correct restoration of the joint line is generally considered as crucial when performing total knee arthroplasty (TKA). During revision knee arthroplasty however, elevation of the joint line occurs frequently. The general belief is that this negatively affects the clinical outcome, but the reasons are still not well understood. Material and methods In this cadaveric in vitro study the biomechanical consequences of joint line elevation were investigated using a previously validated cadaver model simulating active deep knee squats and passive flexion-extension cycles. Knee specimens were sequentially tested after total knee arthroplasty with joint line restoration and after 4 mm joint line elevation. Results The tibia rotated internally with increasing knee flexion during both passive and squatting motion (range: 17° and 7° respectively). Joint line elevation of 4 mm did not make a statistically significant difference. During passive motion, the tibia tended to become slightly more adducted with increasing knee flexion (range: 2°), while it went into slighlty less adduction during squatting (range: –2°). Neither of both trends was influenced by joint line elevation. Also anteroposterior translation of the femoral condyle centres was not affected by joint line elevation, although there was a tendency for a small posterior shift (of about 3 mm) during squatting after joint line elevation. In terms of kinetics, ligaments lengths and length changes, tibiofemoral contact pressures and quadriceps forces all showed the same patterns before and joint line elevation. No statistically significant changes could be detected. Conclusions Our study suggests that joint line elevation by 4 mm in revision total knee arthroplasty does not cause significant kinematic and kinetic differences during passive flexion/extension movement and squatting in the tibio-femoral joint, nor does it affect the elongation patterns of collateral ligaments. Therefore, clinical problems after joint line elevation are probably situated in the patello-femoral joint or caused by joint line elevation of more than 4 mm. PMID:25995746

Design of a simple, lightweight, passive-elastic ankle exoskeleton supporting ankle joint stiffness.

PubMed

Kim, Seyoung; Son, Youngsu; Choi, Sangkyu; Ham, Sangyong; Park, Cheolhoon

2015-09-01

In this study, a passive-elastic ankle exoskeleton (PEAX) with a one-way clutch mechanism was developed and then pilot-tested with vertical jumping to determine whether the PEAX is sufficiently lightweight and comfortable to be used in further biomechanical studies. The PEAX was designed to supplement the function of the Achilles tendon and ligaments as they passively support the ankle torque with their inherent stiffness. The main frame of the PEAX consists of upper and lower parts connected to each other by tension springs (N = 3) and lubricated hinge joints. The upper part has an offset angle of 5° with respect to the vertical line when the springs are in their resting state. Each spring has a slack length of 8 cm and connects the upper part to the tailrod of the lower part in the neutral position. The tailrod freely rotates with low friction but has a limited range of motion due to the stop pin working as a one-way clutch. Because of the one-way clutch system, the tension springs store the elastic energy only due to an ankle dorsiflexion when triggered by the stop pin. This clutch mechanism also has the advantage of preventing any inconvenience during ankle plantarflexion because it does not limit the ankle joint motion during the plantarflexion phase. In pilot jumping tests, all of the subjects reported that the PEAX was comfortable for jumping due to its lightweight (approximately 1 kg) and compact (firmly integrated with shoes) design, and subjects were able to nearly reach their maximum vertical jump heights while wearing the PEAX. During the countermovement jump, elastic energy was stored during dorsiflexion by spring extension and released during plantarflexion by spring restoration, indicating that the passive spring torque (i.e., supportive torque) generated by the ankle exoskeleton partially supported the ankle joint torque throughout the process.

Design of a simple, lightweight, passive-elastic ankle exoskeleton supporting ankle joint stiffness

NASA Astrophysics Data System (ADS)

Kim, Seyoung; Son, Youngsu; Choi, Sangkyu; Ham, Sangyong; Park, Cheolhoon

2015-09-01

In this study, a passive-elastic ankle exoskeleton (PEAX) with a one-way clutch mechanism was developed and then pilot-tested with vertical jumping to determine whether the PEAX is sufficiently lightweight and comfortable to be used in further biomechanical studies. The PEAX was designed to supplement the function of the Achilles tendon and ligaments as they passively support the ankle torque with their inherent stiffness. The main frame of the PEAX consists of upper and lower parts connected to each other by tension springs (N = 3) and lubricated hinge joints. The upper part has an offset angle of 5° with respect to the vertical line when the springs are in their resting state. Each spring has a slack length of 8 cm and connects the upper part to the tailrod of the lower part in the neutral position. The tailrod freely rotates with low friction but has a limited range of motion due to the stop pin working as a one-way clutch. Because of the one-way clutch system, the tension springs store the elastic energy only due to an ankle dorsiflexion when triggered by the stop pin. This clutch mechanism also has the advantage of preventing any inconvenience during ankle plantarflexion because it does not limit the ankle joint motion during the plantarflexion phase. In pilot jumping tests, all of the subjects reported that the PEAX was comfortable for jumping due to its lightweight (approximately 1 kg) and compact (firmly integrated with shoes) design, and subjects were able to nearly reach their maximum vertical jump heights while wearing the PEAX. During the countermovement jump, elastic energy was stored during dorsiflexion by spring extension and released during plantarflexion by spring restoration, indicating that the passive spring torque (i.e., supportive torque) generated by the ankle exoskeleton partially supported the ankle joint torque throughout the process.

Driver assistance system for passive multi-trailer vehicles with haptic steering limitations on the leading unit.

PubMed

Morales, Jesús; Mandow, Anthony; Martínez, Jorge L; Reina, Antonio J; García-Cerezo, Alfonso

2013-04-03

Driving vehicles with one or more passive trailers has difficulties in both forward and backward motion due to inter-unit collisions, jackknife, and lack of visibility. Consequently, advanced driver assistance systems (ADAS) for multi-trailer combinations can be beneficial to accident avoidance as well as to driver comfort. The ADAS proposed in this paper aims to prevent unsafe steering commands by means of a haptic handwheel. Furthermore, when driving in reverse, the steering-wheel and pedals can be used as if the vehicle was driven from the back of the last trailer with visual aid from a rear-view camera. This solution, which can be implemented in drive-by-wire vehicles with hitch angle sensors, profits from two methods previously developed by the authors: safe steering by applying a curvature limitation to the leading unit, and a virtual tractor concept for backward motion that includes the complex case of set-point propagation through on-axle hitches. The paper addresses system requirements and provides implementation details to tele-operate two different off- and on-axle combinations of a tracked mobile robot pulling and pushing two dissimilar trailers.

Driver Assistance System for Passive Multi-Trailer Vehicles with Haptic Steering Limitations on the Leading Unit

PubMed Central

Morales, Jesús; Mandow, Anthony; Martínez, Jorge L.; Reina, Antonio J.; García-Cerezo, Alfonso

2013-01-01

Driving vehicles with one or more passive trailers has difficulties in both forward and backward motion due to inter-unit collisions, jackknife, and lack of visibility. Consequently, advanced driver assistance systems (ADAS) for multi-trailer combinations can be beneficial to accident avoidance as well as to driver comfort. The ADAS proposed in this paper aims to prevent unsafe steering commands by means of a haptic handwheel. Furthermore, when driving in reverse, the steering-wheel and pedals can be used as if the vehicle was driven from the back of the last trailer with visual aid from a rear-view camera. This solution, which can be implemented in drive-by-wire vehicles with hitch angle sensors, profits from two methods previously developed by the authors: safe steering by applying a curvature limitation to the leading unit, and a virtual tractor concept for backward motion that includes the complex case of set-point propagation through on-axle hitches. The paper addresses system requirements and provides implementation details to tele-operate two different off- and on-axle combinations of a tracked mobile robot pulling and pushing two dissimilar trailers. PMID:23552102

Dynamical density functional theory for microswimmers

NASA Astrophysics Data System (ADS)

Menzel, Andreas M.; Saha, Arnab; Hoell, Christian; Löwen, Hartmut

2016-01-01

Dynamical density functional theory (DDFT) has been successfully derived and applied to describe on one hand passive colloidal suspensions, including hydrodynamic interactions between individual particles. On the other hand, active "dry" crowds of self-propelled particles have been characterized using DDFT. Here, we go one essential step further and combine these two approaches. We establish a DDFT for active microswimmer suspensions. For this purpose, simple minimal model microswimmers are introduced. These microswimmers self-propel by setting the surrounding fluid into motion. They hydrodynamically interact with each other through their actively self-induced fluid flows and via the common "passive" hydrodynamic interactions. An effective soft steric repulsion is also taken into account. We derive the DDFT starting from common statistical approaches. Our DDFT is then tested and applied by characterizing a suspension of microswimmers, the motion of which is restricted to a plane within a three-dimensional bulk fluid. Moreover, the swimmers are confined by a radially symmetric trapping potential. In certain parameter ranges, we find rotational symmetry breaking in combination with the formation of a "hydrodynamic pumping state," which has previously been observed in the literature as a result of particle-based simulations. An additional instability of this pumping state is revealed.

Impact of Active Control on Passive Safety Response Characteristics of Sodium-cooled Fast Reactors: I - Theoretical background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Passerini, Stefano; Ponciroli, Roberto; Vilim, Richard B.

Here, the interaction of the active control system with passive safety behavior is investigated for sodium-cooled fast reactors. A claim often made of advanced reactors is that they are passively safe against unprotected upset events. In practice, such upset events are not analyzed in the context of the plant control system, but rather the analyses are performed without considering the normally programmed response of the control system (open-loop approach). This represents an oversimplification of the safety case. The issue of passive safety override arises since the control system commands actuators whose motions have safety consequences. Depending on the upset involvingmore » the control system ( operator error, active control system failure, or inadvertent control system override), an actuator does not necessarily go in the same direction as needed for safety. So neglecting to account for control system action during an unprotected upset is nonconservative from a safety standpoint. It is important then, during the design of the plant, to consider the potential for the control system to work against the inherent and safe regulating effects of purposefully engineered temperature feedbacks.« less

Impact of Active Control on Passive Safety Response Characteristics of Sodium-cooled Fast Reactors: I - Theoretical background

DOE PAGES

Passerini, Stefano; Ponciroli, Roberto; Vilim, Richard B.

2017-06-21

Here, the interaction of the active control system with passive safety behavior is investigated for sodium-cooled fast reactors. A claim often made of advanced reactors is that they are passively safe against unprotected upset events. In practice, such upset events are not analyzed in the context of the plant control system, but rather the analyses are performed without considering the normally programmed response of the control system (open-loop approach). This represents an oversimplification of the safety case. The issue of passive safety override arises since the control system commands actuators whose motions have safety consequences. Depending on the upset involvingmore » the control system ( operator error, active control system failure, or inadvertent control system override), an actuator does not necessarily go in the same direction as needed for safety. So neglecting to account for control system action during an unprotected upset is nonconservative from a safety standpoint. It is important then, during the design of the plant, to consider the potential for the control system to work against the inherent and safe regulating effects of purposefully engineered temperature feedbacks.« less

Flow over a traveling wavy foil with a passively flapping flat plate

NASA Astrophysics Data System (ADS)

Liu, Nansheng; Peng, Yan; Liang, Youwen; Lu, Xiyun

2012-05-01

Flow over a traveling wavy foil with a passively flapping flat plate has been investigated using a multiblock lattice Boltzmann equation and the immersed boundary method. The foil undergoes prescribed undulations in the lateral direction and the rigid flat plate has passive motion determined by the fluid structure interaction. This simplified model is used to study the effect of the fish caudal fin and its flexibility on the locomotion of swimming animals. The flexibility of the caudal fin is modeled by a torsion spring acting about the pivot at the conjuncture of the wavy foil and the flat plate. The study reveals that the passively oscillating flat plate contributes half of the propulsive force. The flexibility, represented by the nondimensional natural frequency F, plays a very important role in the movement and propulsive force generation of the whole body. When the plate is too flexible, the drag force is observed. As the flat plate becomes more rigid, the propulsive force that is generated when the undulation is confined to last part of the wavy foil becomes larger. The steady movement occurs at F=5. These results are consistent with the observations of some swimming animals in nature.

Mechanism for rapid passive-dynamic prey capture in a pitcher plant.

PubMed

Bauer, Ulrike; Paulin, Marion; Robert, Daniel; Sutton, Gregory P

2015-10-27

Plants use rapid movements to disperse seed, spores, or pollen and catch animal prey. Most rapid-release mechanisms only work once and, if repeatable, regaining the prerelease state is a slow and costly process. We present an encompassing mechanism for a rapid, repeatable, passive-dynamic motion used by a carnivorous pitcher plant to catch prey. Nepenthes gracilis uses the impact of rain drops to catapult insects from the underside of the canopy-like pitcher lid into the fluid-filled trap below. High-speed video and laser vibrometry revealed that the lid acts as a torsional spring system, driven by rain drops. During the initial downstroke, the tip of the lid reached peak velocities similar to fast animal motions and an order of magnitude faster than the snap traps of Venus flytraps and catapulting tentacles of the sundew Drosera glanduligera. In contrast to these active movements, the N. gracilis lid oscillation requires neither mechanical preloading nor metabolic energy, and its repeatability is only limited by the intensity and duration of rainfall. The underside of the lid is coated with friction-reducing wax crystals, making insects more vulnerable to perturbations. We show that the trapping success of N. gracilis relies on the combination of material stiffness adapted for momentum transfer and the antiadhesive properties of the wax crystal surface. The impact-driven oscillation of the N. gracilis lid represents a new kind of rapid plant movement with adaptive function. Our findings establish the existence of a continuum between active and passive trapping mechanisms in carnivorous plants.

Mechanism for rapid passive-dynamic prey capture in a pitcher plant

PubMed Central

Bauer, Ulrike; Paulin, Marion; Robert, Daniel; Sutton, Gregory P.

2015-01-01

Plants use rapid movements to disperse seed, spores, or pollen and catch animal prey. Most rapid-release mechanisms only work once and, if repeatable, regaining the prerelease state is a slow and costly process. We present an encompassing mechanism for a rapid, repeatable, passive-dynamic motion used by a carnivorous pitcher plant to catch prey. Nepenthes gracilis uses the impact of rain drops to catapult insects from the underside of the canopy-like pitcher lid into the fluid-filled trap below. High-speed video and laser vibrometry revealed that the lid acts as a torsional spring system, driven by rain drops. During the initial downstroke, the tip of the lid reached peak velocities similar to fast animal motions and an order of magnitude faster than the snap traps of Venus flytraps and catapulting tentacles of the sundew Drosera glanduligera. In contrast to these active movements, the N. gracilis lid oscillation requires neither mechanical preloading nor metabolic energy, and its repeatability is only limited by the intensity and duration of rainfall. The underside of the lid is coated with friction-reducing wax crystals, making insects more vulnerable to perturbations. We show that the trapping success of N. gracilis relies on the combination of material stiffness adapted for momentum transfer and the antiadhesive properties of the wax crystal surface. The impact-driven oscillation of the N. gracilis lid represents a new kind of rapid plant movement with adaptive function. Our findings establish the existence of a continuum between active and passive trapping mechanisms in carnivorous plants. PMID:26438874

A reliability study on brain activation during active and passive arm movements supported by an MRI-compatible robot.

PubMed

Estévez, Natalia; Yu, Ningbo; Brügger, Mike; Villiger, Michael; Hepp-Reymond, Marie-Claude; Riener, Robert; Kollias, Spyros

2014-11-01

In neurorehabilitation, longitudinal assessment of arm movement related brain function in patients with motor disability is challenging due to variability in task performance. MRI-compatible robots monitor and control task performance, yielding more reliable evaluation of brain function over time. The main goals of the present study were first to define the brain network activated while performing active and passive elbow movements with an MRI-compatible arm robot (MaRIA) in healthy subjects, and second to test the reproducibility of this activation over time. For the fMRI analysis two models were compared. In model 1 movement onset and duration were included, whereas in model 2 force and range of motion were added to the analysis. Reliability of brain activation was tested with several statistical approaches applied on individual and group activation maps and on summary statistics. The activated network included mainly the primary motor cortex, primary and secondary somatosensory cortex, superior and inferior parietal cortex, medial and lateral premotor regions, and subcortical structures. Reliability analyses revealed robust activation for active movements with both fMRI models and all the statistical methods used. Imposed passive movements also elicited mainly robust brain activation for individual and group activation maps, and reliability was improved by including additional force and range of motion using model 2. These findings demonstrate that the use of robotic devices, such as MaRIA, can be useful to reliably assess arm movement related brain activation in longitudinal studies and may contribute in studies evaluating therapies and brain plasticity following injury in the nervous system.

Between-Day Reliability of Pre-Participation Screening Components in Pre-Professional Ballet and Contemporary Dancers.

PubMed

Kenny, Sarah J; Palacios-Derflingher, Luz; Owoeye, Oluwatoyosi B A; Whittaker, Jackie L; Emery, Carolyn A

2018-03-15

Critical appraisal of research investigating risk factors for musculoskeletal injury in dancers suggests high quality reliability studies are lacking. The purpose of this study was to determine between-day reliability of pre-participation screening (PPS) components in pre-professional ballet and contemporary dancers. Thirty-eight dancers (35 female, 3 male; median age; 18 years; range: 11 to 30 years) participated. Screening components (Athletic Coping Skills Inventory-28, body mass index, percent total body fat, total bone mineral density, Foot Posture Index-6, hip and ankle range of motion, three lumbopelvic control tasks, unipedal dynamic balance, and the Y-Balance Test) were conducted one week apart. Intra-class correlation coefficients (ICCs: 95% confidence intervals), standard error of measurement, minimal detectable change (MDC), Bland-Altman methods of agreement [95% limits of agreement (LOA)], Cohen's kappa coefficients, standard error, and percent agreements were calculated. Depending on the screening component, ICC estimates ranged from 0.51 to 0.98, kappa coefficients varied between -0.09 and 0.47, and percent agreement spanned 71% to 95%. Wide 95% LOA were demonstrated by Foot Posture Index-6 (right: -6.06, 7.31), passive hip external rotation (right: -9.89, 16.54), and passive supine turnout (left: -15.36, 17.58). The PPS components examined demonstrated moderate to excellent relative reliability with mean between-day differences less than MDC, or sufficient percent agreement, across all assessments. However, due to wide 95% limits of agreement, the Foot Posture Index-6 and passive hip range of motion are not recommended for screening injury risk in pre-professional dancers.

Ankle Joint Angle and Lower Leg Musculotendinous Unit Responses to Cryotherapy.

PubMed

Akehi, Kazuma; Long, Blaine C; Warren, Aric J; Goad, Carla L

2016-09-01

Akehi, K, Long, BC, Warren, AJ, and Goad, CL. Ankle joint angle and lower leg musculotendinous unit responses to cryotherapy. J Strength Cond Res 30(9): 2482-2492, 2016-The use of cold application has been debated for its influence on joint range of motion (ROM) and stiffness. The purpose of this study was to determine whether a 30-minute ice bag application to the plantarflexor muscles or ankle influences passive ankle dorsiflexion ROM and lower leg musculotendinous stiffness (MTS). Thirty-five recreationally active college-aged individuals with no history of lower leg injury 6 months before data collection volunteered. On each testing day, we measured maximum passive ankle dorsiflexion ROM (°) and plantarflexor torque (N·m) on an isokinetic dynamometer to calculate the passive plantarflexor MTS (N·m per degree) at 4 joint angles before, during, and after a treatment. Surface electromyography amplitudes (μV), and skin surface and ambient air temperature (°C) were also measured. Subjects received an ice bag to the posterior lower leg, ankle joint, or nothing for 30 minutes in different days. Ice bag application to the lower leg and ankle did not influence passive ROM (F(12,396) = 0.67, p = 0.78). Passive torque increased after ice bag application to the lower leg (F(12,396) = 2.21, p = 0.011). Passive MTS at the initial joint angle increased after ice bag application to the lower leg (F(12,396) = 2.14, p = 0.014) but not at the other joint angles (p > 0.05). Surface electromyography amplitudes for gastrocnemius and soleus muscles increased after ice application to the lower leg (F(2,66) = 5.61, p = 0.006; F(12,396) = 3.60, p < 0.001). Ice bag application to the lower leg and ankle joint does not alter passive dorsiflexion ROM but increases passive ankle plantarflexor torque in addition to passive ankle plantarflexor MTS at the initial joint angle.

Concept verification of three dimensional free motion simulator for space robot

NASA Technical Reports Server (NTRS)

Okamoto, Osamu; Nakaya, Teruomi; Pokines, Brett

1994-01-01

In the development of automatic assembling technologies for space structures, it is an indispensable matter to investigate and simulate the movements of robot satellites concerned with mission operation. The movement investigation and simulation on the ground will be effectively realized by a free motion simulator. Various types of ground systems for simulating free motion have been proposed and utilized. Some of these methods are a neutral buoyancy system, an air or magnetic suspension system, a passive suspension balance system, and a free flying aircraft or drop tower system. In addition, systems can be simulated by computers using an analytical model. Each free motion simulation method has limitations and well known problems, specifically, disturbance by water viscosity, limited number of degrees-of-freedom, complex dynamics induced by the attachment of the simulation system, short experiment time, and the lack of high speed super-computer simulation systems, respectively. The basic idea presented here is to realize 3-dimensional free motion. This is achieved by combining a spherical air bearing, a cylindrical air bearing, and a flat air bearing. A conventional air bearing system has difficulty realizing free vertical motion suspension. The idea of free vertical suspension is that a cylindrical air bearing and counter balance weight realize vertical free motion. This paper presents a design concept, configuration, and basic performance characteristics of an innovative free motion simulator. A prototype simulator verifies the feasibility of 3-dimensional free motion simulation.

Evaluation of a combination of continuum and truss finite elements in a model of passive and active muscle tissue.

PubMed

Hedenstierna, S; Halldin, P; Brolin, K

2008-12-01

The numerical method of finite elements (FE) is a powerful tool for analysing stresses and strains in the human body. One area of increasing interest is the skeletal musculature. This study evaluated modelling of skeletal muscle tissue using a combination of passive non-linear, viscoelastic solid elements and active Hill-type truss elements, the super-positioned muscle finite element (SMFE). The performance of the combined materials and elements was evaluated for eccentric motions by simulating a tensile experiment from a published study on a stimulated rabbit muscle including three different strain rates. It was also evaluated for isometric and concentric contractions. The resulting stress-strain curves had the same overall pattern as the experiments, with the main limitation being sensitivity to the active force-length relation. It was concluded that the SMFE could model active and passive muscle tissue at constant rate elongations for strains below failure, as well as isometric and concentric contractions.

The Effects of Rapid Sedimentation upon Continental Breakup: Kinematic and Thermal Modeling of the Salton Trough, Southern California, Based upon Recent Seismic Images

NASA Astrophysics Data System (ADS)

Han, L.; Hole, J. A.; Lowell, R. P.; Stock, J. M.; Fuis, G. S.

2016-12-01

The Salton Seismic Imaging Project (SSIP) illuminated crustal and upper mantle structure of the Salton Trough, the northern-most rift segment of the Gulf of California plate boundary. The crust is 17-18 km thick and homogeneous for 100 km in the plate motion direction. New crust is being created by distributed rift magmatism, Colorado River sedimentation, and metamorphism of the sediment. A 5 km thick pre-existing crustal layer may still exist. The crust has not broken apart to enable initiation of seafloor spreading. A one-dimensional time-dependent kinematic and thermal model was developed to simulate these observations. We assume that all crustal layers are stretched uniformly during extension. Distributed mafic magmatism and sedimentation are added simultaneously to compensate for the crustal thinning. The ratio of magmatism to sedimentation is constrained by the seismic observations. Heat is transported by thermal conduction and by advection due to stretching of the crust. A constant temperature boundary at the Moho is used to represent partial melting in the upper mantle. Assuming a constant plate motion rate, the zone of active rifting extends linearly with time. The crustal thickness and internal structure also evolve with time. The model constraints are the observed seismic structure and heat flow. The model rapidly reaches quasi-steady state, and could continue for many millions of years. The observed seismic structure and heat flow are reproduced after 3 Myr. The yield strength profile calculated from lithology and model temperature indicates that ductile deformation in the middle and lower crust dominates the crustal rheology. Rapid sedimentation delays crustal breakup and the initiation of seafloor spreading by maintaining the thickness of the crust and keeping it predominantly ductile. This process probably occurs wherever a large river flows into an active rift driven by far-field extension. It may have built passive margins in many locations globally, such as the Gulf of Mexico. This type of passive margin consists of mostly new crust created by magmatism and metamorphism of sediment. Along such margins, metamorphosed sediment could be misinterpreted as stretched pre-existing continental crust.

Intercomparison of active, passive and continuous instruments for radon and radon progeny measurements in the EML chamber and test facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, A.C.; Knutson, E.O.; Tu, K.W.

1995-12-01

The results from the May 1995 Intercomparison of Active, Passive and Continuous Instruments for Radon and Radon Progeny Measurement conducted in the EML radon exposure and test facility are presented. Represented were 13 participants that measure radon with open faced and diffusion barrier activated carbon collectors, 10 with nuclear alpha track detectors, 9 with short-term and long-term electret/ionization chambers, and 13 with active and passive commercial electronic continuous monitors. For radon progeny, there were four participants that came in person to take part in the grab sampling methodology for measuring individual radon progeny and the potential alpha energy concentration (PAEC).more » There were 11 participants with continuous and integrating commercial electronic instruments that are used for measuring the PAEC. The results indicate that all the tested instruments that measure radon fulfill their intended purpose. All instruments and methods used for grab sampling for radon progeny did very well. However, most of the continuous and integrating electronic instruments used for measuring the PAEC or working level appear to underestimate the potential risk from radon progeny when the concentration of particles onto which the radon progeny are attached is <5,000 cm{sup -3}.« less

Disappearance of the inversion effect during memory-guided tracking of scrambled biological motion.

PubMed

Jiang, Changhao; Yue, Guang H; Chen, Tingting; Ding, Jinhong

2016-08-01

The human visual system is highly sensitive to biological motion. Even when a point-light walker is temporarily occluded from view by other objects, our eyes are still able to maintain tracking continuity. To investigate how the visual system establishes a correspondence between the biological-motion stimuli visible before and after the disruption, we used the occlusion paradigm with biological-motion stimuli that were intact or scrambled. The results showed that during visually guided tracking, both the observers' predicted times and predictive smooth pursuit were more accurate for upright biological motion (intact and scrambled) than for inverted biological motion. During memory-guided tracking, however, the processing advantage for upright as compared with inverted biological motion was not found in the scrambled condition, but in the intact condition only. This suggests that spatial location information alone is not sufficient to build and maintain the representational continuity of the biological motion across the occlusion, and that the object identity may act as an important information source in visual tracking. The inversion effect disappeared when the scrambled biological motion was occluded, which indicates that when biological motion is temporarily occluded and there is a complete absence of visual feedback signals, an oculomotor prediction is executed to maintain the tracking continuity, which is established not only by updating the target's spatial location, but also by the retrieval of identity information stored in long-term memory.

Active-passive vibration absorber of beam-cart-seesaw system with piezoelectric transducers

NASA Astrophysics Data System (ADS)

Lin, J.; Huang, C. J.; Chang, Julian; Wang, S.-W.

2010-09-01

In contrast with fully controllable systems, a super articulated mechanical system (SAMS) is a controlled underactuated mechanical system in which the dimensions of the configuration space exceed the dimensions of the control input space. The objectives of the research are to develop a novel SAMS model which is called beam-cart-seesaw system, and renovate a novel approach for achieving a high performance active-passive piezoelectric vibration absorber for such system. The system consists of two mobile carts, which are coupled via rack and pinion mechanics to two parallel tracks mounted on pneumatic rodless cylinders. One cart carries an elastic beam, and the other cart acts as a counterbalance. One adjustable counterweight mass is also installed underneath the seesaw to serve as a passive damping mechanism to absorb impact and shock energy. The motion and control of a Bernoulli-Euler beam subjected to the modified cart/seesaw system are analyzed first. Moreover, gray relational grade is utilized to investigate the sensitivity of tuning the active proportional-integral-derivative (PID) controller to achieve desired vibration suppression performance. Consequently, it is shown that the active-passive vibration absorber can not only provide passive damping, but can also enhance the active action authority. The proposed software/hardware platform can also be profitable for the standardization of laboratory equipment, as well as for the development of entertainment tools.

Assessment of passive knee stiffness and viscosity in individuals with spinal cord injury using pendulum test.

PubMed

Joghtaei, Mahmoud; Arab, Amir Massoud; Hashemi-Nasl, Hamed; Joghataei, Mohammad Taghi; Tokhi, Mohammad Osman

2015-03-01

Stiffness and viscosity represent passive resistances to joint motion related with the structural properties of the joint tissue and of the musculotendinous complex. Both parameters can be affected in patients with spinal cord injury (SCI). The purpose of this study was to measure passive knee stiffness and viscosity in patients with SCI with paraplegia and healthy subjects using Wartenberg pendulum test. Non-experimental, cross-sectional, case-control design. An outpatient physical therapy clinic, University of social welfare and Rehabilitation Science, Iran. A sample of convenience sample of 30 subjects participated in the study. Subjects were categorized into two groups: individuals with paraplegic SCI (n = 15, age: 34.60 ± 9.18 years) and 15 able-bodied individuals as control group (n = 15, age: 30.66 ± 11.13 years). Not applicable. Passive pendulum test of Wartenberg was used to measure passive viscous-elastic parameters of the knee (stiffness, viscosity) in all subjects. Statistical analysis (independent t-test) revealed significant difference in the joint stiffness between healthy subjects and those with paraplegic SCI (P = 0.01). However, no significant difference was found in the viscosity between two groups (P = 0.17). Except for first peak flexion angle, all other displacement kinematic parameters exhibited no statistically significant difference between normal subjects and subjects with SCI. Patients with SCI have significantly greater joint stiffness compared to able-bodied subjects.

Effects of muscle activation on shear between human soleus and gastrocnemius muscles.

PubMed

Finni, T; Cronin, N J; Mayfield, D; Lichtwark, G A; Cresswell, A G

2017-01-01

Lateral connections between muscles provide pathways for myofascial force transmission. To elucidate whether these pathways have functional roles in vivo, we examined whether activation could alter the shear between the soleus (SOL) and lateral gastrocnemius (LG) muscles. We hypothesized that selective activation of LG would decrease the stretch-induced shear between LG and SOL. Eleven volunteers underwent a series of knee joint manipulations where plantar flexion force, LG, and SOL muscle fascicle lengths and relative displacement of aponeuroses between the muscles were obtained. Data during a passive full range of motion were recorded, followed by 20° knee extension stretches in both passive conditions and with selective electrical stimulation of LG. During active stretch, plantar flexion force was 22% greater (P < 0.05) and relative displacement of aponeuroses was smaller than during passive stretch (P < 0.05). Soleus fascicle length changes did not differ between passive and active stretches but LG fascicles stretched less in the active than passive condition when the stretch began at angles of 70° and 90° of knee flexion (P < 0.05). The activity-induced decrease in the relative displacement of SOL and LG suggests stronger (stiffer) connectivity between the two muscles, at least at flexed knee joint angles, which may serve to facilitate myofascial force transmission. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Structural evolution of tunneling oxide passivating contact upon thermal annealing.

PubMed

Choi, Sungjin; Min, Kwan Hong; Jeong, Myeong Sang; Lee, Jeong In; Kang, Min Gu; Song, Hee-Eun; Kang, Yoonmook; Lee, Hae-Seok; Kim, Donghwan; Kim, Ka-Hyun

2017-10-16

We report on the structural evolution of tunneling oxide passivating contact (TOPCon) for high efficient solar cells upon thermal annealing. The evolution of doped hydrogenated amorphous silicon (a-Si:H) into polycrystalline-silicon (poly-Si) by thermal annealing was accompanied with significant structural changes. Annealing at 600 °C for one minute introduced an increase in the implied open circuit voltage (V oc ) due to the hydrogen motion, but the implied V oc decreased again at 600 °C for five minutes. At annealing temperature above 800 °C, a-Si:H crystallized and formed poly-Si and thickness of tunneling oxide slightly decreased. The thickness of the interface tunneling oxide gradually decreased and the pinholes are formed through the tunneling oxide at a higher annealing temperature up to 1000 °C, which introduced the deteriorated carrier selectivity of the TOPCon structure. Our results indicate a correlation between the structural evolution of the TOPCon passivating contact and its passivation property at different stages of structural transition from the a-Si:H to the poly-Si as well as changes in the thickness profile of the tunneling oxide upon thermal annealing. Our result suggests that there is an optimum thickness of the tunneling oxide for passivating electron contact, in a range between 1.2 to 1.5 nm.

31 CFR 800.223 - Solely for the purpose of passive investment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (Continued) OFFICE OF INVESTMENT SECURITY, DEPARTMENT OF THE TREASURY REGULATIONS PERTAINING TO MERGERS, ACQUISITIONS, AND TAKEOVERS BY FOREIGN PERSONS Definitions § 800.223 Solely for the purpose of passive... Board of Directors. The acquisition by Corporation A of a voting interest in Corporation B is not solely...

Damping in flapping flight and its implications for manoeuvring, scaling and evolution.

PubMed

Hedrick, Tyson L

2011-12-15

Flying animals exhibit remarkable degrees of both stability and manoeuvrability. Our understanding of these capabilities has recently been improved by the identification of a source of passive damping specific to flapping flight. Examining how this damping effect scales among different species and how it affects active manoeuvres as well as recovery from perturbations provides general insights into the flight of insects, birds and bats. These new damping models offer a means to predict manoeuvrability and stability for a wide variety of flying animals using prior reports of the morphology and flapping motions of these species. Furthermore, the presence of passive damping is likely to have facilitated the evolution of powered flight in animals by providing a stability benefit associated with flapping.

Design and preliminary accuracy studies of an MRI-guided transrectal prostate intervention system.

PubMed

Krieger, Axel; Csoma, Csaba; Iordachital, Iulian I; Guion, Peter; Singh, Anurag K; Fichtinger, Gabor; Whitcomb, Louis L

2007-01-01

This paper reports a novel system for magnetic resonance imaging (MRI) guided transrectal prostate interventions, such as needle biopsy, fiducial marker placement, and therapy delivery. The system utilizes a hybrid tracking method, comprised of passive fiducial tracking for initial registration and subsequent incremental motion measurement along the degrees of freedom using fiber-optical encoders and mechanical scales. Targeting accuracy of the system is evaluated in prostate phantom experiments. Achieved targeting accuracy and procedure times were found to compare favorably with existing systems using passive and active tracking methods. Moreover, the portable design of the system using only standard MRI image sequences and minimal custom scanner interfacing allows the system to be easily used on different MRI scanners.

Intercomparison of active, passive and continuous instruments for radon and radon progeny measurements in the EML chamber and test facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarpitta, S.C.; Tu, K.W.; Fisenne, I.M.

1996-10-01

Results are presented from the Fifth Intercomparison of Active, Passive and Continuous Instruments for Radon and Radon Progeny Measurements conducted in the EML radon exposure and test facility in May 1996. In total, thirty-four government, private and academic facilities participated in the exercise with over 170 passive and electronic devices exposed in the EML test chamber. During the first week of the exercise, passive and continuous measuring devices were exposed (usually in quadruplicate) to about 1,280 Bq m{sup {minus}3} {sup 222}Rn for 1--7 days. Radon progeny measurements were made during the second week of the exercise. The results indicate thatmore » all of the tested devices that measure radon gas performed well and fulfill their intended purpose. The grand mean (GM) ratio of the participants` reported values to the EML values, for all four radon device categories, was 0.99 {plus_minus} 0.08. Eighty-five percent of all the radon measuring devices that were exposed in the EML radon test chamber were within {plus_minus}1 standard deviation (SD) of the EML reference values. For the most part, radon progeny measurements were also quite good as compared to the EML values. The GM ratio for the 10 continuous PAEC instruments was 0.90 {plus_minus} 0.12 with 75% of the devices within 1 SD of the EML reference values. Most of the continuous and integrating electronic instruments used for measuring the PAEC underestimated the EML values by about 10--15% probably because the concentration of particles onto which the radon progeny were attached was low (1,200--3,800 particles cm{sup {minus}3}). The equilibrium factor at that particle concentration level was 0.10--0.22.« less

Supporting Stroke Motor Recovery Through a Mobile Application: A Pilot Study.

PubMed

Lawson, Sonia; Tang, Ziying; Feng, Jinjuan

Neuroplasticity and motor learning are promoted with repetitive movement, appropriate challenge, and performance feedback. ARMStrokes, a smartphone application, incorporates these qualities to support motor recovery. Engaging exercises are easily accessible for improved compliance. In a multiple-case, mixed-methods pilot study, the potential of this technology for stroke motor recovery was examined. Exercises calibrated to the participant's skill level targeted forearm, elbow, and shoulder motions for a 6-wk protocol. Visual, auditory, and vibration feedback promoted self-assessment. Pre- and posttest data from 6 chronic stroke survivors who used the app in different ways (i.e., to measure active or passive motion, to track endurance) demonstrated improvements in accuracy of movements, fatigue, range of motion, and performance of daily activities. Statistically significant changes were not obtained with this pilot study. Further study on the efficacy of this technology is supported. Copyright © 2017 by the American Occupational Therapy Association, Inc.

Movement amplitude and tempo change in piano performance

NASA Astrophysics Data System (ADS)

Palmer, Caroline

2004-05-01

Music performance places stringent temporal and cognitive demands on individuals that should yield large speed/accuracy tradeoffs. Skilled piano performance, however, shows consistently high accuracy across a wide variety of rates. Movement amplitude may affect the speed/accuracy tradeoff, so that high accuracy can be obtained even at very fast tempi. The contribution of movement amplitude changes in rate (tempo) is investigated with motion capture. Cameras recorded pianists with passive markers on hands and fingers, who performed on an electronic (MIDI) keyboard. Pianists performed short melodies at faster and faster tempi until they made errors (altering the speed/accuracy function). Variability of finger movements in the three motion planes indicated most change in the plane perpendicular to the keyboard across tempi. Surprisingly, peak amplitudes of motion before striking the keys increased as tempo increased. Increased movement amplitudes at faster rates may reduce or compensate for speed/accuracy tradeoffs. [Work supported by Canada Research Chairs program, HIMH R01 45764.

Spatial Transformation of the Vestibulo-Ocular Reflex during Spaceflight

NASA Technical Reports Server (NTRS)

Clement, Gilles; Wood, Scott J.; Reschke, Millard F.

1996-01-01

It was hypothesized that the absence of the gravitational reference cues may be responsible for adaptive changes in the vestibulo-ocular reflex (VOR). These changes result in the alteration of the direction of the compensatory slow phase (SP) eye movements in microgravity. In order to test this hypothesis, the direction of the VOR SP relative to head motion was investigated in three astronauts during and after an eight-day orbital flight by passive sinusoidal pitch or yaw angular motion at two frequencies. The results of the inflight and postflight testing are considered. The observed deviation between VOR SP and head motion suggests that spatial transformation in the VOR occurred during adaptation to microgravity. It is considered that, although this spatial transformation might be due to a sensory bias, it may reflect central changes in the reference system used for spatial orientation in microgravity.

A passively controlled appendage deployment system for the San Marco D/L spacecraft

NASA Technical Reports Server (NTRS)

Lang, W. E.; Frisch, H. P.; Schwartz, D. A.

1984-01-01

The analytical simulation of deployment dynamics of these two axis concepts as well as the evolution of practical designs for the add on deployable inertia boom units is described. With the boom free to swing back in response to Coriolis forces as well as outwards in response to centrifugal forces, the kinematics of motion are complex but admit the possibility of absorbing deployment energy in frictional or other damping devices about the radial axis, where large amplitude motions can occur and where the design envelope allows more available volume. An acceptable range is defined for frictional damping for any given spin rate. Inadequate damping allows boom motions which strike the spacecraft; excessive damping causes the boom to swing out and latch with damaging violence. The acceptable range is a design parameter and must accommodate spin rate tolerance and also the tolerance and repeatability of the damping mechanisms.

Hypoalgesic effect of a passive accessory mobilisation technique in patients with lateral ankle pain.

PubMed

Yeo, Hwee Koon; Wright, Anthony

2011-08-01

A randomised, double blind, repeated measures study was conducted to investigate the initial effects of an accessory mobilisation technique applied to the ankle joint in 13 patients with a unilateral sub-acute ankle supination injury. Ankle dorsiflexion range of motion, pressure pain threshold, visual analogue scale rating of pain during functional activity and ankle functional scores were assessed before and after application of treatment, manual contact control and no contact control conditions. There were significant improvements in ankle dorsiflexion range of motion (p = 0.000) and pressure pain threshold (p = 0.000) during the treatment condition. However no significant effects were observed for the other measures. These findings demonstrate that mobilisation of the ankle joint can produce an initial hypoalgesic effect and an improvement in ankle dorsiflexion range of motion. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Motor characteristics determine the rheological behavior of a suspension of microswimmers

NASA Astrophysics Data System (ADS)

Karmakar, Richa; Gulvady, Ranjit; Tirumkudulu, Mahesh S.; Venkatesh, K. V.

2014-07-01

A suspension of motile cells exhibits complex rheological properties due to their collective motion. We measure the shear viscosity of a suspension of Escherichia coli strains varying in motor characteristics such as duration of run and tumble. At low cell densities, all strains irrespective of their motor characteristics exhibit a linear increase in viscosity with cell density suggesting that the cells behave as a suspension of passive rods with an effective aspect ratio set by the motor characteristics of the bacteria. As the cell density is increased beyond a critical value, the viscosity drops sharply signaling the presence of strongly coordinated motion among bacteria. The critical density depends not only on the magnitude of shear but also the motor characteristics of individual cells. High shear rate disrupts the coordinated motion reducing its behavior, once again, to a suspension of inactive particles.

Activity induced phase transition in mixtures of active and passive agents

NASA Astrophysics Data System (ADS)

Sinha Mahapatra, Pallab; Kulkarni, Ajinkya

2017-11-01

Collective behaviors of self-propelling agents are ubiquitous in nature that produces interesting patterns. The objective of this study is to investigate the phase transition in mixtures of active and inert agents suspended in a liquid. A modified version of the Vicsek Model has been used (see Ref.), where the particles are modeled as soft disks with finite mass, confined in a square domain. The particles are required to align their local motion to their immediate neighborhood, similar to the Vicsek model. We identified the transition from disorganized thermal-like motion to an organized vortical motion. We analyzed the nature of the transition by using different order parameters. Furthermore the switching between the phases has been investigated via artificial nucleation of randomly picked active agents spanning the entire domain. Finally the motivation for this phase transition has been explained via average dissipation and the mean square displacement (MSD) of the agents.

Coiled to diffuse: Brownian motion of a helical bacterium.

PubMed

Butenko, Alexander V; Mogilko, Emma; Amitai, Lee; Pokroy, Boaz; Sloutskin, Eli

2012-09-11

We employ real-time three-dimensional confocal microscopy to follow the Brownian motion of a fixed helically shaped Leptospira interrogans (LI) bacterium. We extract from our measurements the translational and the rotational diffusion coefficients of this bacterium. A simple theoretical model is suggested, perfectly reproducing the experimental diffusion coefficients, with no tunable parameters. An older theoretical model, where edge effects are neglected, dramatically underestimates the observed rates of translation. Interestingly, the coiling of LI increases its rotational diffusion coefficient by a factor of 5, compared to a (hypothetical) rectified bacterium of the same contour length. Moreover, the translational diffusion coefficients would have decreased by a factor of ~1.5, if LI were rectified. This suggests that the spiral shape of the spirochaete bacteria, in addition to being employed for their active twisting motion, may also increase the ability of these bacteria to explore the surrounding fluid by passive Brownian diffusion.

Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion.

PubMed

Lee, Dong-Jin; Lee, Sun-Kyu

2015-01-01

This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

Brief communication: Cineradiographic analysis of the chimpanzee (Pan troglodytes) talonavicular and calcaneocuboid joints.

PubMed

Thompson, Nathan E; Holowka, Nicholas B; O'Neill, Matthew C; Larson, Susan G

2014-08-01

During terrestrial locomotion, chimpanzees exhibit dorsiflexion of the midfoot between midstance and toe-off of stance phase, a phenomenon that has been called the "midtarsal break." This motion is generally absent during human bipedalism, and in chimpanzees is associated with more mobile foot joints than in humans. However, the contribution of individual foot joints to overall foot mobility in chimpanzees is poorly understood, particularly on the medial side of the foot. The talonavicular (TN) and calcaneocuboid (CC) joints have both been suggested to contribute significantly to midfoot mobility and to the midtarsal break in chimpanzees. To evaluate the relative magnitude of motion that can occur at these joints, we tracked skeletal motion of the hindfoot and midfoot during passive plantarflexion and dorsiflexion manipulations using cineradiography. The sagittal plane range of motion was 38 ± 10° at the TN joint and 14 ± 8° at the CC joint. This finding indicates that the TN joint is more mobile than the CC joint during ankle plantarflexion-dorsiflexion. We suggest that the larger range of motion at the TN joint during dorsiflexion is associated with a rotation (inversion-eversion) across the transverse tarsal joint, which may occur in addition to sagittal plane motion. © 2014 Wiley Periodicals, Inc.

Miniature DMFCs with passive thermal-fluids management system

NASA Astrophysics Data System (ADS)

Guo, Zhen; Faghri, Amir

A new miniature DMFC system that includes a fuel cell stack, a fuel tank and a passive ancillary system (termed "thermal-fluids management system" in this paper) is presented. The thermal-fluids management system utilizes passive approaches for fuel storage and delivery, air breathing, water management, CO 2 release and thermal management. With 5.1 g of neat methanol in the fuel cartridge, a prototype has successfully demonstrated 18 h of continuous operation with total power output of 1.56 Wh.

Diode-pumped passively mode-locked and passively stabilized Nd3+:BaY2F8 laser

NASA Astrophysics Data System (ADS)

Agnesi, Antonio; Guandalini, Annalisa; Tomaselli, Alessandra; Sani, Elisa; Toncelli, Alessandra; Tonelli, Mauro

2004-07-01

Continuous-wave mode locking (CW-ML) of a diode-pumped Nd3+:BaY2F8 laser is reported for the first time to our knowledge. Pulses as short as 4.8 ps were measured with a total output power of almost equal to 1 W at 1049 nm, corresponding to 3.4 W of absorbed power from the pump diode at 806 nm. A novel technique for passive stabilization of CW-ML has been demonstrated.

Techniques for detumbling a disabled space base

NASA Technical Reports Server (NTRS)

Kaplan, M. H.

1973-01-01

Techniques and conceptual devices for carrying out detumbling operations are examined, and progress in the development of these concepts is discussed. Devices which reduce tumble to simple spin through active linear motion of a small mass are described, together with a Module for Automatic Dock and Detumble (MADD) that could perform an orbital transfer from the shuttle in order to track and dock at a preselected point on the distressed craft. Once docked, MADD could apply torques by firing thrustors to detumble the passive vehicle. Optimum combinations of mass-motion and external devices for various situation should be developed. The need for completely formulating the automatic control logic of MADD is also emphasized.

24 CFR 1720.320 - Motions for extension of time.

Code of Federal Regulations, 2010 CFR

2010-04-01

... continuances in any proceeding may be ordered on a motion by the administrative law judge or on the motion of... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Motions for extension of time. 1720... PRACTICE Adjudicatory Proceedings Motions § 1720.320 Motions for extension of time. As a matter of...

24 CFR 1720.320 - Motions for extension of time.

Code of Federal Regulations, 2014 CFR

2014-04-01

... continuances in any proceeding may be ordered on a motion by the administrative law judge or on the motion of... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Motions for extension of time. 1720... PRACTICE Adjudicatory Proceedings Motions § 1720.320 Motions for extension of time. As a matter of...

24 CFR 1720.320 - Motions for extension of time.

Code of Federal Regulations, 2011 CFR

2011-04-01

... continuances in any proceeding may be ordered on a motion by the administrative law judge or on the motion of... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Motions for extension of time. 1720... PRACTICE Adjudicatory Proceedings Motions § 1720.320 Motions for extension of time. As a matter of...

24 CFR 1720.320 - Motions for extension of time.

Code of Federal Regulations, 2013 CFR

2013-04-01

... continuances in any proceeding may be ordered on a motion by the administrative law judge or on the motion of... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Motions for extension of time. 1720... PRACTICE Adjudicatory Proceedings Motions § 1720.320 Motions for extension of time. As a matter of...

24 CFR 1720.320 - Motions for extension of time.

Code of Federal Regulations, 2012 CFR

2012-04-01

... continuances in any proceeding may be ordered on a motion by the administrative law judge or on the motion of... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Motions for extension of time. 1720... PRACTICE Adjudicatory Proceedings Motions § 1720.320 Motions for extension of time. As a matter of...

The neural encoding of self-generated and externally applied movement: implications for the perception of self-motion and spatial memory

PubMed Central

Cullen, Kathleen E.

2014-01-01

The vestibular system is vital for maintaining an accurate representation of self-motion. As one moves (or is moved) toward a new place in the environment, signals from the vestibular sensors are relayed to higher-order centers. It is generally assumed the vestibular system provides a veridical representation of head motion to these centers for the perception of self-motion and spatial memory. In support of this idea, evidence from lesion studies suggests that vestibular inputs are required for the directional tuning of head direction cells in the limbic system as well as neurons in areas of multimodal association cortex. However, recent investigations in monkeys and mice challenge the notion that early vestibular pathways encode an absolute representation of head motion. Instead, processing at the first central stage is inherently multimodal. This minireview highlights recent progress that has been made towards understanding how the brain processes and interprets self-motion signals encoded by the vestibular otoliths and semicircular canals during everyday life. The following interrelated questions are considered. What information is available to the higher-order centers that contribute to self-motion perception? How do we distinguish between our own self-generated movements and those of the external world? And lastly, what are the implications of differences in the processing of these active vs. passive movements for spatial memory? PMID:24454282

Finite-element model of the active organ of Corti

PubMed Central

Elliott, Stephen J.; Baumgart, Johannes

2016-01-01

The cochlear amplifier that provides our hearing with its extraordinary sensitivity and selectivity is thought to be the result of an active biomechanical process within the sensory auditory organ, the organ of Corti. Although imaging techniques are developing rapidly, it is not currently possible, in a fully active cochlea, to obtain detailed measurements of the motion of individual elements within a cross section of the organ of Corti. This motion is predicted using a two-dimensional finite-element model. The various solid components are modelled using elastic elements, the outer hair cells (OHCs) as piezoelectric elements and the perilymph and endolymph as viscous and nearly incompressible fluid elements. The model is validated by comparison with existing measurements of the motions within the passive organ of Corti, calculated when it is driven either acoustically, by the fluid pressure or electrically, by excitation of the OHCs. The transverse basilar membrane (BM) motion and the shearing motion between the tectorial membrane and the reticular lamina are calculated for these two excitation modes. The fully active response of the BM to acoustic excitation is predicted using a linear superposition of the calculated responses and an assumed frequency response for the OHC feedback. PMID:26888950

Dynamics of Marine Zooplankton: Social Behavior, Ecological Interactions, and Physically-Induced Variability

DTIC Science & Technology

2008-02-01

97 3.3.2 Steady-state solutions ..... ........................ 100 3.4 Ecosystem dynamics ...... ............................. 102 3.4.1 Fast ...zooplankton motion is decoupled from biological ac- tivities, as calculated in Flier] et al. (1999). When the diffusion rate is fast compared to phytoplankton...homogenize the zooplankton distribution, which remains spatially more intermit - tent than a passive scalar field. The last panel shows the index for

Use of passive ambient ozone (O3) samplers in vegetation effects assessment

USGS Publications Warehouse

Krupa, S.; Nosal, M.; Peterson, D.L.

2001-01-01

A stochastistic, Weibull probability model was developed and verified to simulate the underlying frequency distributions of hourly ozone (O3) concentrations (exposure dynamics) using the single, weekly mean values obtained from a passive (sodium nitrite absorbent) sampler. The simulation was based on the data derived from a co-located continuous monitor. Although at the moment the model output may be considered as being specific to the elevation and location of the study site, the results were extremely good. This effort for the approximation of the O3 exposure dynamics can be extended to other sites with similar data sets and in developing a generalized understanding of the stochastic O3 exposure-plant response relationships, conferring measurable benefits to the future use of passive O3 samplers, in the absence of continuous monitoring. Copyright ?? 2000 Elsevier Science Ltd.

Nd:(Gd0.3Y0.7)2SiO5 crystal: A novel efficient dual-wavelength continuous-wave medium

NASA Astrophysics Data System (ADS)

Xu, Xiaodong; Di, Juqing; Zhang, Jian; Tang, Dingyuan; Xu, Jun

2016-05-01

Efficient dual-wavelength continuous-wave (CW) and passively Q-switched laser operation of Nd:(Gd0.3Y0.7)2SiO5 crystal were investigated for the first time to our knowledge. Maximum CW output power of 2.3 W was obtained under the absorbed pump power of 4.6 W, corresponding to the slope efficiency of 55%. Dual-wavelength CW laser with respective wavelengths around 1074 nm and 1078 nm were achieved. With Cr4+:YAG as the saturable absorber, passive Q-switched performance was obtained. The slope efficiency of passively Q-switched operation was 45%. The shortest pulse width, the corresponding pulse energy and peak power were calculated to be 13.1 ns, 50.2 μJ and 3.8 kW, respectively.

The science of spinal motion palpation: a review and update with implications for assessment and intervention

PubMed Central

Nyberg, Richard Edward; Russell Smith, A

2013-01-01

Spinal motion palpation (SMP) is a standard component of a manual therapy examination despite questionable reliability. The present research is inconclusive as to the relevance of the findings from SMP, with respect to the patient’s pain complaints. Differences in the testing methods and interpretation of spinal mobility testing are problematic. If SMP is to be a meaningful component of a spinal examination, the methods for testing and interpretation must be carefully scrutinized. The intent of this narrative review is to facilitate a better understanding of how SMP should provide the examiner with relevant information for assessment and treatment of patients with spinal pain disorders. The concept of just noticeable difference is presented and applied to SMP as a suggestion for determining the neutral zone behavior of a spinal segment. In addition, the use of a lighter, or more passive receptive palpation technique, is considered as a means for increasing tactile discrimination of spinal movement behavior. Further understanding of the scientific basis of testing SMP may improve intra- and inter-examiner reliability. The significance of the findings from SMP should be considered in context of the patient’s functional problem. Methodological changes may be indicated for the performance of SMP techniques, such as central posterior-anterior (PA) pressure and passive intervertebral motion tests, in order to improve reliability. Instructors of manual therapy involved in teaching SMP should be knowledgeable of the neurophysiological processes of touch sensation so as to best advise students in the application of the various testing techniques. PMID:24421627

Investigation of hexagonal boron nitride as an atomically thin corrosion passivation coating in aqueous solution.

PubMed

Zhang, Jing; Yang, Yingchao; Lou, Jun

2016-09-09

Hexagonal boron nitride (h-BN) atomic layers were utilized as a passivation coating in this study. A large-area continuous h-BN thin film was grown on nickel foil using a chemical vapor deposition method and then transferred onto sputtered copper as a corrosion passivation coating. The corrosion passivation performance in a Na2SO4 solution of bare and coated copper was investigated by electrochemical methods including cyclic voltammetry (CV), Tafel polarization and electrochemical impedance spectroscopy (EIS). CV and Tafel analysis indicate that the h-BN coating could effectively suppress the anodic dissolution of copper. The EIS fitting result suggests that defects are the dominant leakage source on h-BN films, and improved anti-corrosion performances could be achieved by further passivating these defects.

The long- and short-term variability of breathing induced tumor motion in lung and liver over the course of a radiotherapy treatment.

PubMed

Dhont, Jennifer; Vandemeulebroucke, Jef; Burghelea, Manuela; Poels, Kenneth; Depuydt, Tom; Van Den Begin, Robbe; Jaudet, Cyril; Collen, Christine; Engels, Benedikt; Reynders, Truus; Boussaer, Marlies; Gevaert, Thierry; De Ridder, Mark; Verellen, Dirk

2018-02-01

To evaluate the short and long-term variability of breathing induced tumor motion. 3D tumor motion of 19 lung and 18 liver lesions captured over the course of an SBRT treatment were evaluated and compared to the motion on 4D-CT. An implanted fiducial could be used for unambiguous motion information. Fast orthogonal fluoroscopy (FF) sequences, included in the treatment workflow, were used to evaluate motion during treatment. Several motion parameters were compared between different FF sequences from the same fraction to evaluate the intrafraction variability. To assess interfraction variability, amplitude and hysteresis were compared between fractions and with the 3D tumor motion registered by 4D-CT. Population based margins, necessary on top of the ITV to capture all motion variability, were calculated based on the motion captured during treatment. Baseline drift in the cranio-caudal (CC) or anterior-poster (AP) direction is significant (ie. >5 mm) for a large group of patients, in contrary to intrafraction amplitude and hysteresis variability. However, a correlation between intrafraction amplitude variability and mean motion amplitude was found (Pearson's correlation coefficient, r = 0.72, p < 10 -4 ). Interfraction variability in amplitude is significant for 46% of all lesions. As such, 4D-CT accurately captures the motion during treatment for some fractions but not for all. Accounting for motion variability during treatment increases the PTV margins in all directions, most significantly in CC from 5 mm to 13.7 mm for lung and 8.0 mm for liver. Both short-term and day-to-day tumor motion variability can be significant, especially for lesions moving with amplitudes above 7 mm. Abandoning passive motion management strategies in favor of more active ones is advised. Copyright © 2017 Elsevier B.V. All rights reserved.

Two-Dimensional Cochlear Micromechanics Measured In Vivo Demonstrate Radial Tuning within the Mouse Organ of Corti

PubMed Central

Lee, Hee Yoon; Raphael, Patrick D.; Xia, Anping; Kim, Jinkyung; Grillet, Nicolas; Applegate, Brian E.; Ellerbee Bowden, Audrey K.

2016-01-01

The exquisite sensitivity and frequency discrimination of mammalian hearing underlie the ability to understand complex speech in noise. This requires force generation by cochlear outer hair cells (OHCs) to amplify the basilar membrane traveling wave; however, it is unclear how amplification is achieved with sharp frequency tuning. Here we investigated the origin of tuning by measuring sound-induced 2-D vibrations within the mouse organ of Corti in vivo. Our goal was to determine the transfer function relating the radial shear between the structures that deflect the OHC bundle, the tectorial membrane and reticular lamina, to the transverse motion of the basilar membrane. We found that, after normalizing their responses to the vibration of the basilar membrane, the radial vibrations of the tectorial membrane and reticular lamina were tuned. The radial tuning peaked at a higher frequency than transverse basilar membrane tuning in the passive, postmortem condition. The radial tuning was similar in dead mice, indicating that this reflected passive, not active, mechanics. These findings were exaggerated in TectaC1509G/C1509G mice, where the tectorial membrane is detached from OHC stereocilia, arguing that the tuning of radial vibrations within the hair cell epithelium is distinct from tectorial membrane tuning. Together, these results reveal a passive, frequency-dependent contribution to cochlear filtering that is independent of basilar membrane filtering. These data argue that passive mechanics within the organ of Corti sharpen frequency selectivity by defining which OHCs enhance the vibration of the basilar membrane, thereby tuning the gain of cochlear amplification. SIGNIFICANCE STATEMENT Outer hair cells amplify the traveling wave within the mammalian cochlea. The resultant gain and frequency sharpening are necessary for speech discrimination, particularly in the presence of background noise. Here we measured the 2-D motion of the organ of Corti in mice and found that the structures that stimulate the outer hair cell stereocilia, the tectorial membrane and reticular lamina, were sharply tuned in the radial direction. Radial tuning was similar in dead mice and in mice lacking a tectorial membrane. This suggests that radial tuning comes from passive mechanics within the hair cell epithelium, and that these mechanics, at least in part, may tune the gain of cochlear amplification. PMID:27488636

Resistance to flexural fatigue of Reciproc R25 files under continuous rotation and reciprocating movement.

PubMed

Gavini, Giulio; Caldeira, Celso Luiz; Akisue, Eduardo; Candeiro, George Táccio de Miranda; Kawakami, Dirce Akemi Sacaguti

2012-05-01

The aim of the present work was to evaluate the resistance to flexural fatigue of Reciproc R25 nickel-titanium files, 25 mm, used in continuous rotation motion or reciprocation motion, in dynamic assays device. Thirty-six Reciproc R25 files were divided into 2 groups (n = 18) according to kinematics applied, continuous rotary (group CR) and reciprocation motion (group RM). The files were submitted to dynamic assays device moved by an electric engine with 300 rpm of speed that permitted the reproduction of pecking motion. The files run on a ring's groove of temperate steel, simulating instrumentation of a curved root canal with 40° and 5 mm of curvature radius. The fracture of file was detected by sensor of device, and the time was marked. The data were analyzed statistically by Student's t test, with level of significance of 95%. The instruments moved by reciprocating movement reached significantly higher numbers of cycles before fracture (mean, 1787.78 cycles) when compared with instruments moved by continuous rotary (mean, 816.39 cycles). The results showed that the reciprocation motion improves flexural fatigue resistance in nickel-titanium instrument Reciproc R25 when compared with continuous rotation movement. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Forces and energetics of intermittent swimming

NASA Astrophysics Data System (ADS)

Floryan, Daniel; Van Buren, Tyler; Smits, Alexander J.

2017-08-01

Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by particle image velocimetry (PIV) flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.

Acute Effects of the Different Intensity of Static Stretching on Flexibility and Isometric Muscle Force.

PubMed

Kataura, Satoshi; Suzuki, Shigeyuki; Matsuo, Shingo; Hatano, Genki; Iwata, Masahiro; Yokoi, Kazuaki; Tsuchida, Wakako; Banno, Yasuhiro; Asai, Yuji

2017-12-01

Kataura, S, Suzuki, S, Matsuo, S, Hatano, G, Iwata, M, Yokoi, K, Tsuchida, W, Banno, Y, and Asai, Y. Acute effects of the different intensity of static stretching on flexibility and isometric muscle force. J Strength Cond Res 31(12): 3403-3410, 2017-In various fields, static stretching is commonly performed to improve flexibility, whereas the acute effects of different stretch intensities are unclear. Therefore, we investigated the acute effects of different stretch intensities on flexibility and muscle force. Eighteen healthy participants (9 men and 9 women) performed 180-second static stretches of the right hamstrings at 80, 100, and 120% of maximum tolerable intensity without stretching pain, in random order. The following outcomes were assessed as markers of lower limb function and flexibility: static passive torque (SPT), range of motion (ROM), passive joint (muscle-tendon) stiffness, passive torque (PT) at onset of pain, and isometric muscle force. Static passive torque was significantly decreased after all stretching intensities (p ≤ 0.05). Compared with before stretching at 100 and 120% intensities, ROM and PT were significantly increased after stretching (p ≤ 0.05), and passive stiffness (p = 0.05) and isometric muscle force (p ≤ 0.05) were significantly decreased. In addition, ROM was significantly greater after stretching at 100 and 120% than at 80%, and passive stiffness was significantly lower after 120% than after 80% (p ≤ 0.05). However, all measurements except SPT were unchanged after 80% intensity. There was a weak positive correlation between the intensities of stretching and the relative change for SPT (p ≤ 0.05), a moderate positive correlation with ROM (p ≤ 0.05), and a moderate positive correlation with passive stiffness (p ≤ 0.05). These results indicate that static stretching at greater intensity is more effective for increasing ROM and decreasing passive muscle-tendon stiffness.

Assessment of Psychophysiological Responses During Motion Sickness Testing

NASA Technical Reports Server (NTRS)

Stoud, Cynthia S.; Toscano, William B.; Cowings, Patricia; Freidman, Gary

1994-01-01

The purpose of this investigation is to evaluate a methodology designed to accurately trace the temporal progression of motion sickness and space motion sickness symptoms. With this method, subjects continuously monitor their own motion sickness symptoms during exposure to a provocative stimulus as symptoms occur, in contrast to previous methods during which subjects report symptoms verbally at discrete time intervals. This method not only is comparable to previous methods in the type of symptoms that subjects report, but subjects report symptoms more frequently. Frequent reporting of motion sickness symptoms allows researchers to detail the waxing and waning of motion sickness symptoms for each individual. Previous research has shown that physiological responses to motion sickness stimuli are characterized by unique individual differences in response patterns. By improving our assessment of motion sickness symptoms with continuous monitoring of symptoms, the relationship between specific physiological responses and sickness levels can be more accurately determined for each individual. Results from this study show significant positive relationships between skin conductance levels and symptom levels for ten individuals; a significant positive relationship between temperature and symptom levels for 5 of 10 individuals; and both positive and negative relationships between respiration, heart rate, blood volume pulse and symptom levels. Continuous monitoring of motion sickness symptoms can be used to more accurately assess motion sickness to aid in the evaluation of countermeasures. In addition, recognition of the onset of symptoms that are strongly related to specific physiological responses could be used as cues to initiate procedures (e.g., Autogenic Feedback Training) to prevent the development of severe motion sickness symptoms.

Inertial acceleration as a measure of linear vection: An alternative to magnitude estimation. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Carpenter-Smith, Theodore R.; Futamura, Robert G.; Parker, Donald E.

1995-01-01

The present study focused on the development of a procedure to assess perceived self-motion induced by visual surround motion - vection. Using an apparatus that permitted independent control of visual and inertial stimuli, prone observers were translated along their head x-axis (fore/aft). The observers' task was to report the direction of self-motion during passive forward and backward translations of their bodies coupled with exposure to various visual surround conditions. The proportion of 'forward' responses was used to calculate each observer's point of subjective equality (PSE) for each surround condition. The results showed that the moving visual stimulus produced a significant shift in the PSE when data from the moving surround condition were compared with the stationary surround and no-vision condition. Further, the results indicated that vection increased monotonically with surround velocities between 4 and 40/s. It was concluded that linear vection can be measured in terms of changes in the amplitude of whole-body inertial acceleration required to elicit equivalent numbers of 'forward' and 'backward' self-motion reports.

Multimodal transport and dispersion of organelles in narrow tubular cells

NASA Astrophysics Data System (ADS)

Mogre, Saurabh S.; Koslover, Elena F.

2018-04-01

Intracellular components explore the cytoplasm via active motor-driven transport in conjunction with passive diffusion. We model the motion of organelles in narrow tubular cells using analytical techniques and numerical simulations to study the efficiency of different transport modes in achieving various cellular objectives. Our model describes length and time scales over which each transport mode dominates organelle motion, along with various metrics to quantify exploration of intracellular space. For organelles that search for a specific target, we obtain the average capture time for given transport parameters and show that diffusion and active motion contribute to target capture in the biologically relevant regime. Because many organelles have been found to tether to microtubules when not engaged in active motion, we study the interplay between immobilization due to tethering and increased probability of active transport. We derive parameter-dependent conditions under which tethering enhances long-range transport and improves the target capture time. These results shed light on the optimization of intracellular transport machinery and provide experimentally testable predictions for the effects of transport regulation mechanisms such as tethering.

Physiological asymmetry of trunk ranging and pelvis motility: an anatomo-functional study in 80 healthy subjects.

PubMed

Macchi, Claudio; Biricolti, Claudia; Cappelli, Lorenza; Galli, Francesca; Molino-Lova, Raffaele; Cecchi, Francesca; Corigliano, Alvaro; Miniati, Benedetta; Conti, Andrea A; Gulisano, Massimo; Catini, Claudio; Gensini, Gian Franco

2002-01-01

A key feature in physiotherapeutic treatment of patients with motion disturbances is the appropriate ranging of the trunk and pelvis motility. Eighty subjects randomly selected and free from known pathology of the muscular-skeletal and/or of the neurological system classed into four groups according to the age and the sex have been assessed, by using a new, simple and easy administrable tool. Our results demonstrate that the new measurement tool showed a very low intra- and inter-observer variability, that healthy subjects showed a more adduced and elevated right scapula if compared to the contralateral one and, as regard as the pelvic motion, a broader joint excursion in passive motion compared with active motion in the overall group, a broader joint excursion in young subjects compared with elderly ones, and a broader joint excursion in female subjects compared with males subjects. In conclusion our study allowed to identify a range of physiological asymmetry and pelvis motility. Such a range of physiological asymmetry might be useful as a reference for the physiotherapists.

Apparatus and methods for continuous beam fourier transform mass spectrometry

DOEpatents

McLuckey, Scott A.; Goeringer, Douglas E.

2002-01-01

A continuous beam Fourier transform mass spectrometer in which a sample of ions to be analyzed is trapped in a trapping field, and the ions in the range of the mass-to-charge ratios to be analyzed are excited at their characteristic frequencies of motion by a continuous excitation signal. The excited ions in resonant motions generate real or image currents continuously which can be detected and processed to provide a mass spectrum.

The Effect of Supination and Pronation on Wrist Range of Motion

PubMed Central

Kane, Patrick M.; Vopat, Bryan G.; Got, Christopher; Mansuripur, Kaveh; Akelman, Edward

2014-01-01

Wrist range of motion (ROM) is a combination of complex osseous articulations and intricate soft tissue constraints. It has been proposed that forearm rotation contributes significantly to carpal kinematics. However, no studies have investigated whether supination or pronation influence this course of motion. The purpose of this study is to examine whether supination and pronation affect the mechanical axis of the wrist. After being screened for gross anatomic abnormalities, six upper extremity cadaver specimens (three matched pairs) were fixed to a custom-designed jig that allows 24 different directions of wrist motion. Each specimen was tested in three separate forearm positions: neutral, full supination, and full pronation. Moments of ± 2 Nm were applied, and the applied moment versus wrist rotation data were recorded. Forearm position did not significantly (p > 0.31) affect the ROM values of the wrist. In forearm neutral, supination, and pronation positions the envelope of wrist ROM values was ellipsoidal in shape, consistent with prior neutral forearm biomechanical testing. The major axis of the ellipse was oriented in a radial extension to ulnar flexion direction, with the largest ROM in ulnar flexion. We hypothesized that forearm position would influence wrist ROM. However, our biomechanical testing showed no statistically significant difference in the orientation of the mechanical axis nor the passive ROM of the wrist. The primary passive mechanical axis in all three forearm positions tested (neutral, supination, and pronation) was aligned with radial extension and ulnar flexion. Although it has been shown that forearm position affects various radioulnar, radiocarpal, and ulnocarpal ligamentous tensions and lengths, it appears that wrist ROM is independent of forearm position. Consequently we feel our biomechanical testing illustrates that wrist ROM is primarily dependent on the osseous articulations of the carpus. Additionally, given that no change is observed in wrist ROM relative to forearm position, the significance of the contribution of the distal radioulnar joint (DRUJ) to wrist kinematics is debatable. PMID:25097812

Improved single- and multi-contact life-time testing of dental restorative materials using key characteristics of the human masticatory system and a force/position-controlled robotic dental wear simulator.

PubMed

Raabe, D; Harrison, A; Ireland, A; Alemzadeh, K; Sandy, J; Dogramadzi, S; Melhuish, C; Burgess, S

2012-03-01

This paper presents a new in vitro wear simulator based on spatial parallel kinematics and a biologically inspired implicit force/position hybrid controller to replicate chewing movements and dental wear formations on dental components, such as crowns, bridges or a full set of teeth. The human mandible, guided by passive structures such as posterior teeth and the two temporomandibular joints, moves with up to 6 degrees of freedom (DOF) in Cartesian space. The currently available wear simulators lack the ability to perform these chewing movements. In many cases, their lack of sufficient DOF enables them only to replicate the sliding motion of a single occlusal contact point by neglecting rotational movements and the motion along one Cartesian axis. The motion and forces of more than one occlusal contact points cannot accurately be replicated by these instruments. Furthermore, the majority of wear simulators are unable to control simultaneously the main wear-affecting parameters, considering abrasive mechanical wear, which are the occlusal sliding motion and bite forces in the constraint contact phase of the human chewing cycle. It has been shown that such discrepancies between the true in vivo and the simulated in vitro condition influence the outcome and the quality of wear studies. This can be improved by implementing biological features of the human masticatory system such as tooth compliance realized through the passive action of the periodontal ligament and active bite force control realized though the central nervous system using feedback from periodontal preceptors. The simulator described in this paper can be used for single- and multi-occlusal contact testing due to its kinematics and ability to exactly replicate human translational and rotational mandibular movements with up to 6 DOF without neglecting movements along or around the three Cartesian axes. Recorded human mandibular motion and occlusal force data are the reference inputs of the simulator. Experimental studies of wear using this simulator demonstrate that integrating the biological feature of combined force/position hybrid control in dental material testing improves the linearity and reduces the variability of results. In addition, it has been shown that present biaxially operated dental wear simulators are likely to provide misleading results in comparative in vitro/in vivo one-contact studies due to neglecting the occlusal sliding motion in one plane which could introduce an error of up to 49% since occlusal sliding motion D and volumetric wear loss V(loss) are proportional.

Performance and robustness of hybrid model predictive control for controllable dampers in building models

NASA Astrophysics Data System (ADS)

Johnson, Erik A.; Elhaddad, Wael M.; Wojtkiewicz, Steven F.

2016-04-01

A variety of strategies have been developed over the past few decades to determine controllable damping device forces to mitigate the response of structures and mechanical systems to natural hazards and other excitations. These "smart" damping devices produce forces through passive means but have properties that can be controlled in real time, based on sensor measurements of response across the structure, to dramatically reduce structural motion by exploiting more than the local "information" that is available to purely passive devices. A common strategy is to design optimal damping forces using active control approaches and then try to reproduce those forces with the smart damper. However, these design forces, for some structures and performance objectives, may achieve high performance by selectively adding energy, which cannot be replicated by a controllable damping device, causing the smart damper performance to fall far short of what an active system would provide. The authors have recently demonstrated that a model predictive control strategy using hybrid system models, which utilize both continuous and binary states (the latter to capture the switching behavior between dissipative and non-dissipative forces), can provide reductions in structural response on the order of 50% relative to the conventional clipped-optimal design strategy. This paper explores the robustness of this newly proposed control strategy through evaluating controllable damper performance when the structure model differs from the nominal one used to design the damping strategy. Results from the application to a two-degree-of-freedom structure model confirms the robustness of the proposed strategy.

Enhanced visible light generation in an active microcavity via third-harmonic conversion beyond the non-depletion approximation

NASA Astrophysics Data System (ADS)

Yu, Rong; Ding, Chunling; Wang, Jiangpeng; Zhang, Duo

2017-12-01

We explore the possibility of using an active doubly resonant microtoroid resonator to produce high-efficiency third-harmonic generation (THG) by exploiting optical third-order nonlinearity. In a microresonator, the active fundamental mode is coherently driven with a continuous-wave input laser at the telecommunication wavelength (1550 nm), and then, the visible THG signal (517 nm) is monitored via an individual bus waveguide. We thoroughly compare our results with those obtained from the conventional passive (i.e., loss) microtoroid resonator by a systematic analysis and detailed numerical simulations based on the Heisenberg-Langevin equations of motion. It is shown that the achievable THG spectrum features an ultralow critical input power. The THG power transmission can be significantly enhanced by about three orders of magnitude at a low input power of 0.1 μ W as compared with the obtained results in the passive microtoroid resonator THG system. Moreover, the THG efficiency can reach up to 100% with optical critical input power as low as a few microwatts. In turn, the analytical expressions of the critical intracavity intensity of the light in the microcavity, the critical input pump power, and the maximum THG efficiency are obtained. The enhanced THG power transmission and high conversion efficiency are attributed to a gain-induced loss compensation in the microtoroid resonator, reducing the effective loss felt by the resonator photons. With state-of-the art technologies in the field of solid-state resonators, including but not limited to microtoroids, the proposed THG scheme is experimentally realizable.

Extensibility of the hamstrings is best explained by mechanical components of muscle contraction, not behavioral measures in individuals with chronic low back pain.

PubMed

Marshall, Paul W M; Mannion, Jamie; Murphy, Bernadette A

2009-08-01

To examine the relationship between hamstring extensibility by use of the instrumented straight leg raise; mechanical components of muscle contraction, including muscle recruitment, passive torque measures of tissue stiffness, and eccentric strength; and self-reported measures of pain and disability. Cross-sectional study. University laboratory. Twenty-one individuals with chronic nonspecific axial lower back pain and 15 healthy control subjects. Instrumented straight leg raise, concentric and eccentric hamstring strength, self-reported measures of pain, disability, fear avoidance, general health and well-being Objective measures included hamstring extensibility, hamstring muscle stiffness, absolute and relative concentric/eccentric strength, concentric/eccentric strength ratios. Self-reported measures included Oswestry disability index, visual analog pain scale, fear avoidance beliefs, and general health and well being. Patients with lower back pain had lower range of motion, greater changes in muscle stiffness, and impaired concentric-to-eccentric strength levels. Stepwise regression identified measures of stiffness as significantly predicting hamstring extensibility (adjusted r(2) = 0.58, F = 23.76, P < .001). Self-reported measures were not associated with extensibility. Gender differences were noted for passive stiffness and absolute strength. For women, later onset of the medial hamstrings also was associated with greater hamstring extensibility. Decreased extensibility of the hamstrings was associated with increased passive stiffness during the common range of motion (20 to 50 degrees ). Impaired stretch tolerance is associated with actual mechanical restriction, not behavioral measures indicating increased pain or fear-avoidant behavior. With no relationship to actual disability and contradictory findings in the literature for the relationship of the hamstrings to the mechanics of the low back, it is unclear whether decreased hamstring extensibility should be targeted in rehabilitation programs for axial lower back pain.

Sagittal plane kinematics of passive dorsiflexion of the foot in adolescent athletes.

PubMed

Gatt, Alfred; Chockalingam, Nachiappan; Falzon, Owen

2013-01-01

Although assessment of passive maximum foot dorsiflexion angle is performed routinely, there is a paucity of information regarding adolescents' foot and foot segment motion during this procedure. There are currently no trials investigating the kinematics of the adolescent foot during passive foot dorsiflexion. A six-camera optoelectronic motion capture system was used to collect kinematic data using the Oxford Foot Model. Eight female amateur gymnasts 11 to 16 years old (mean age, 13.2 years; mean height, 1.5 m) participated in the study. A dorsiflexing force was applied to the forefoot until reaching maximum resistance with the foot placed in the neutral, pronated, and supinated positions in random order. The maximum foot dorsiflexion angle and the range of movement of the forefoot to hindfoot, tibia to forefoot, and tibia to hindfoot angles were computed. Mean ± SD maximum foot dorsiflexion angles were 36.3° ± 7.2° for pronated, 36.9° ± 4.0° for neutral, and 33.0° ± 4.9° for supinated postures. One-way repeated-measures analysis of variance results were nonsignificant among the 3 groups (P = .70), as were the forefoot to tibia angle and hindfoot to tibia angle variations (P = .091 and P = .188, respectively). Forefoot to hindfoot angle increased with the application of force, indicating that in adolescents, the forefoot does not lock at any particular posture as portrayed by the traditional Rootian paradigm. Participants had very flexible foot dorsiflexion, unlike those in another study assessing adolescent athletes. This finding, together with nonsignificant statistical results, implies that foot dorsiflexion measurement may be performed at any foot posture without notably affecting results.

Rotation, narrowing and preferential reactivation of brittle structures during oblique rifting

NASA Astrophysics Data System (ADS)

Huismans, R. S.; Duclaux, G.; May, D.

2017-12-01

Occurrence of multiple faults populations with contrasting orientations in oblique continental rifts and passive margins has long sparked debate about relative timing of deformation events and tectonic interpretations. Here, we use high-resolution three-dimensional thermo-mechanical numerical modeling to characterize the evolution of the structural style associated with moderately oblique rifting in the continental lithosphere. Automatic analysis of the distribution of active extensional shears at the surface of the model demonstrates a characteristic deformation sequence. We show that upon localization, Phase 1 wide oblique en-échelon grabens develop, limited by extensional shears oriented orthogonal to σ3. Subsequent widening of the grabens is accompanied by a progressive rotation of the Phase 1 extensional shears that become sub-orthogonal the plate motion direction. Phase 2 is marked by narrowing of active deformation resulting from thinning of the continental lithosphere and development of a second-generation of extensional shears. During Phase 2 deformation localizes both on plate motion direction-orthogonal structures that reactivate rotated Phase 1 shears, and on new oblique structures orthogonal to σ3. Finally, Phase 3 consists in the oblique rupture of the continental lithosphere and produces an oceanic domain where oblique ridge segments are linked with highly oblique accommodation zones. We conclude that while new structures form normal to σ3 in an oblique rift, progressive rotation and long-term reactivation of Phase 1 structures promotes orthorhombic fault systems, critical to accommodate upper crustal extension and control oblique passive margin architecture. The distribution, orientation, and evolution of frictional-plastic structures observed in our models is remarkably similar to documented fault populations in the Gulf of Aden conjugate passive margins, which developed in moderately oblique extensional settings.

Examination of the torque required to passively palmar abduct the thumb CMC joint in a pediatric population with hemiplegia and stroke.

PubMed

Stirling, Leia; Ahmad, Mona Qureshi; Kelty-Stephen, Damian; Correia, Annette

2015-12-16

Many activities of daily living involve precision grasping and bimanual manipulation, such as putting toothpaste on a toothbrush or feeding oneself. However, children afflicted by stroke, cerebral palsy, or traumatic brain injury may have lost or never had the ability to actively and accurately control the thumb. To translate insights from adult rehabilitation robotics to innovative therapies for hand rehabilitation in pediatric care, specifically for thumb deformities, an understanding of the torque needed to abduct the thumb to assist grasping tasks is required. Participants (n=16, 10 female, 13.2±3.1 years) had an upper extremity evaluation and measures were made of their passive range of motion, anthropometrics, and torques to abduct the thumb for both their affected and non-affected sides. Torque measures were made using a custom wrist orthosis that was adjusted for each participant. The torque to achieve maximum abduction was 1.47±0.61inlb for the non-affected side and 1.51±0.68inlb for the affected side, with a maximum recorded value of 4.87inlb. The overall maximum applied torque was observed during adduction and was 5.10inlb. We saw variation in the applied torque, which could have been due to the applied torques by the Occupational Therapist or the participant actively assisting or resisting the motion rather than remaining passive. We expect similar muscle and participant variation to exist with an assistive device. Thus, the data presented here can be used to inform the specifications for the development of an assistive thumb orthosis for children with "thumb-in-palm" deformity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of eccentric training on the plantar flexor muscle-tendon tissue properties.

PubMed

Mahieu, Nele Nathalie; McNair, Peter; Cools, Ann; D'Haen, Caroline; Vandermeulen, Katrien; Witvrouw, Erik

2008-01-01

It has been shown that eccentric training can be effective in the rehabilitation of patients with Achilles tendonopathy. The mechanism behind these results is not clear. However, there is evidence that tendons are able to respond to repeated forces by altering their structure and composition, and, thus, their mechanical properties change. In this regard, the objective of the present study was to investigate whether eccentric training affects the mechanical properties of the plantar flexor's muscle-tendon tissue properties. Seventy-four healthy subjects were randomized into two groups: an eccentric training group and a control group. The eccentric training group performed a 6-wk eccentric training program for the calf muscles. Before and after this period, all subjects were evaluated for dorsiflexion range of motion using universal goniometry, passive resistive torque of the plantar flexors, and stiffness of the Achilles tendon. Passive resistive torque was measured during ankle dorsiflexion on an isokinetic dynamometer. Stiffness of the Achilles tendon was assessed using a dynamometer, in combination with ultrasonography. The results of the study reveal that the dorsiflexion range of motion was significantly increased only in the eccentric training group. The eccentric heel drop program also resulted in a significant decrease of the passive resistive torque of the plantar flexors (from 16.423 +/- 0.827 to 12.651 +/- 0.617 N.m). The stiffness of the Achilles tendon did not change significantly as a result of training. These findings provide evidence that an eccentric training program results in changes to some of the mechanical properties of the plantar flexor muscles. These changes were thought to be associated with modifications to structure rather than to stretch tolerance.

Is ultrasound-guided injection more effective in chronic subacromial bursitis?

PubMed

Hsieh, Lin-Fen; Hsu, Wei-Chun; Lin, Yi-Jia; Wu, Shih-Hui; Chang, Kae-Chwen; Chang, Hsiao-Lan

2013-12-01

Although ultrasound (US)-guided subacromial injection has shown increased accuracy in needle placement, whether US-guided injection produces better clinical outcome is still controversial. Therefore, this study aimed to compare the efficacy of subacromial corticosteroid injection under US guidance with palpation-guided subacromial injection in patients with chronic subacromial bursitis. Patients with chronic subacromial bursitis were randomized to a US-guided injection group and a palpation-guided injection group. The subjects in each group were injected with a mixture of 0.5 mL dexamethasone suspension and 3 mL lidocaine into the subacromial bursa. The primary outcome measures were the visual analog scale for pain and active and passive ranges of motion of the affected shoulder. Secondary outcome measures were the Shoulder Pain and Disability Index, the Shoulder Disability Questionnaire, and the 36-item Short-Form Health Survey (SF-36). The primary outcome measures were evaluated before, immediately, 1 wk, and 1 month after the injection; the secondary outcome measures were evaluated before, 1 wk, and 1 month after the injection. Of the 145 subjects screened, 46 in each group completed the study. Significantly greater improvement in passive shoulder abduction and in physical functioning and vitality scores on the SF-36 were observed in the US-guided group. The pre- and postinjection within-group comparison revealed significant improvement in the visual analog scale for pain and range of motion, as well as in the Shoulder Pain and Disability Index, Shoulder Disability Questionnaire, and SF-36 scores, in both groups. The US-guided subacromial injection technique produced significantly greater improvements in passive shoulder abduction and in some items of the SF-36. US is effective in guiding the needle into the subacromial bursa in patients with chronic subacromial bursitis.

Grade II whiplash injuries to the neck: what is the benefit for patients treated by different physical therapy modalities?

PubMed Central

Dehner, Christoph; Elbel, Martin; Strobel, Philipp; Scheich, Matthias; Schneider, Florian; Krischak, Gert; Kramer, Michael

2009-01-01

Background In a majority of cases, whiplash injuries are a domain of conservative therapy. Nevertheless it remains unclear whether physical therapy is of medical or economic benefit in patients with whiplash injuries. Methods Seventy patients with acute Quebec Task Force (QTF) grade II whiplash injuries were randomized to two therapy groups and received either active (APT) or passive (PPT) physical therapy. Patients were compared with regard to pain and range of motion with data obtained in an earlier study from a group with grade II whiplash injuries in which the therapy recommendation had been "act as usual" (AAU; n = 20). The above-mentioned parameters were assessed at 24 hours and two months after the injury. Furthermore patients' period of disability was documented after two months. Results After two months, patients in both the APT and PPT groups showed significant improvement in the median period of disability (active: 14 days; passive: 14 days) compared to the AAU group (49 days). No group difference was observed with regard to median improvement in range of motion (active: 120°; passive: 108°; activity as usual: 70°). The median pain reduction was significantly greater in the APT group (50.5) than in the PPT (39.2) or AAU group (28.8). Conclusion Our data show that active physical therapy results in enhanced pain reduction and shortening of post-injury disability. Therefore, active physical therapy should be considered the treatment of choice in patients with QTF grade II whiplash injuries. Trial registration The study complied with applicable German law and with the principles of the Helsinki Declaration and was approved by the institutional ethics commission. PMID:19149880

Clinical descriptive measures of shoulder range of motion for a healthy, young and physically active cohort.

PubMed

Vairo, Giampietr L; Duffey, Michele L; Owens, Brett D; Cameron, Kenneth L

2012-09-10

The objective of this innovative research study was to describe clinical shoulder complex range of motion (ROM) measures for a young, healthy, and physically active population. This investigation represents a cross-sectional experiment conducted at a military academy-based sports medicine center. Military cadets with no history of shoulder complex injury were assessed within two months of enrollment in the academy; 548 men (18.8 ± 1.0 yr, 75.2 ± 12.2 kg, 178.3 ± 7.4 cm) and 74 women (18.7 ± 0.9 yr, 63.2 ± 8.9 kg, 165.2 ± 6.9 cm) participated. Descriptive measures included cross-body adduction (CAD), flexion (FLX), external rotation (ER0) with the shoulder complex in adduction and elbow flexed to 90°, internal and external rotation (IR, ER) with the shoulder complex at 90° of abduction and elbow flexed to 90° as well as arc (ARC) of IR-ER using standardized clinical quantification techniques. Bilateral and sex differences were evaluated using dependent and independent t-tests, respectively. Percentiles by arm dominance and sex were also calculated for all ROM measures. Data were normally distributed. Active and passive ROM measures indicated significant bilateral differences (P < 0.05) except for ARC. Sex differences (P < 0.05) were noted for active and passive CAD, FLX and ER0 for the dominant arm as well as active and passive CAD, FLX and ARC for the non-dominant arm. These original data provide descriptive measures for shoulder complex ROM excursions, assisting sports medicine practitioners in potentially identifying clinical deficiencies and functional outcomes following shoulder injury.

Acute effect of constant torque and angle stretching on range of motion, muscle passive properties, and stretch discomfort perception.

PubMed

Cabido, Christian E T; Bergamini, Juliana C; Andrade, André G P; Lima, Fernando V; Menzel, Hans J; Chagas, Mauro H

2014-04-01

The aim of the present study was to compare the acute effects of constant torque (CT) and constant angle (CA) stretching exercises on the maximum range of motion (ROMmax), passive stiffness (PS), and ROM corresponding to the first sensation of tightness in the posterior thigh (FSTROM). Twenty-three sedentary men (age, 19-33 years) went through 1 familiarization session and afterward proceeded randomly to both CA and CT treatment stretching conditions, on separate days. An isokinetic dynamometer was used to analyze hamstring muscles during passive knee extension. The subjects performed 4 stretches of 30 seconds each with a 15-second interval between them. In the CA stretching, the subject reached a certain ROM (95% of ROMmax), and the angle was kept constant. However, in the CT stretching exercise, the volunteer reached a certain resistance torque (corresponding to 95% of ROMmax) and it was kept constant. The results showed an increase in ROMmax for both CA and CT (p < 0.001), but the increase was greater for CT than for CA (CA vs. CT in poststretching, p = 0.002). Although the PS decreased for both CA and CT (p < 0.001), the decrease was greater for CT than for CA (CA vs. CT in poststretching, p = 0.002). The FSTROM increased for both CA and CT, but the increase for CT was greater than that for CA (CA vs. CT in poststretching, p = 0.003). The greater increase in ROMmax for the CT stretch may be explained by greater changes in the biomechanical properties of the muscle-tendon unit and stretch tolerance, as indicated by the results of PS and FSTROM.

Effects of Inductively Coupled Plasma Hydrogen on Long-Wavelength Infrared HgCdTe Photodiodes

NASA Astrophysics Data System (ADS)

Boieriu, P.; Buurma, C.; Bommena, R.; Blissett, C.; Grein, C.; Sivananthan, S.

2013-12-01

Bulk passivation of semiconductors with hydrogen continues to be investigated for its potential to improve device performance. In this work, hydrogen-only inductively coupled plasma (ICP) was used to incorporate hydrogen into long-wavelength infrared HgCdTe photodiodes grown by molecular-beam epitaxy. Fully fabricated devices exposed to ICP showed statistically significant increases in zero-bias impedance values, improved uniformity, and decreased dark currents. HgCdTe photodiodes on Si substrates passivated with amorphous ZnS exhibited reductions in shunt currents, whereas devices on CdZnTe substrates passivated with polycrystalline CdTe exhibited reduced surface leakage, suggesting that hydrogen passivates defects in bulk HgCdTe and in CdTe.

Comparing Effectiveness of Active and Passive Client Follow-Up Approaches in Sustaining the Continued Use of Long Acting Reversible Contraceptives (LARC) in Rural Punjab: A Multicentre, Non-Inferiority Trial

PubMed Central

Hameed, Waqas; Azmat, Syed Khurram; Ali, Moazzam; Ishaque, Muhammad; Abbas, Ghazunfer; Munroe, Erik; Harrison, Rebecca; Shamsi, Wajahat Hussain; Mustafa, Ghulam; Khan, Omar Farooq; Ali, Safdar; Ahmed, Aftab

2016-01-01

Background The use of long-acting reversible contraceptive (LARC) methods is very low in Pakistan with high discontinuation rates mainly attributed to method-related side effects. Mixed evidence is available on the effectiveness of different client follow-up approaches used to ensure method continuation. We compared the effectiveness of active and passive follow-up approaches in sustaining the use of LARC—and within ‘active’ follow-up, we further compared a telephone versus home-based approach in rural Punjab, Pakistan. Methods This was a 12-month multicentre non-inferiority trial conducted in twenty-two (16 rural- and 6 urban-based) franchised reproductive healthcare facilities in district Chakwal of Punjab province, between November 2013 and December 2014. The study comprised of three groups of LARC clients: a) home-based follow-up, b) telephone-based follow-up, and c) passive or needs-based follow-up. Participants in the first two study groups received counselling on scheduled follow-up from the field workers at 1, 3, 6, 9, and 12 month post-insertion whereas participants in the third group were asked to contact the health facility if in need of medical assistance relating to LARC method use. Study participants were recruited with equal allocation to each study group, but participants were not randomized. The analyses are based on 1,246 LARC (intra-uterine contraceptive device and implant) users that completed approximately 12-months of follow-up. The non-inferiority margin was kept at five percentage points for the comparison of active and passive follow-up and six percentage points for telephone and home-based approach. The primary outcome was cumulative probability of method continuation at 12-month among LARC users. Results Women recruited in home-based, telephone-based, and passive groups were 400, 419 and 427, respectively. The cumulative probability of LARC continuation at 12 month was 87.6% (95% CI 83.8 to 90.6) among women who received home-based follow-up; 89.1% (95% CI 85.7, 91.8) who received telephone-based follow-up; and 83.8% (95% CI 79.8 to 87.1) who were in the passive or needs-based follow-up group. The probability of continuation among women who were actively followed-up by field health educators—either through home-based visit or telephone-based follow-up was, 88.3% (95% CI 85.9 to 90.0). An adjusted risk difference of -4.1 (95% CI -7.8 to -0.28; p-value = 0.035) was estimated between active and passive follow-up. Whereas, within the active client follow-up, the telephone-based follow-up was found to be as effective as the home-based follow-up with an adjusted risk difference of 1.8 (95% CI -2.7 to 6.4; p-value = 0.431). Conclusion A passive follow-up approach was 5% inferior to an active follow-up approach; whereas telephone-based follow-up was as effective as the home-based visits in sustaining the use of LARC, and was far more resource efficient. Therefore, active follow-up could improve method continuation especially in the critical post-insertion period. PMID:27584088

An MRI-Compatible Robotic System With Hybrid Tracking for MRI-Guided Prostate Intervention

PubMed Central

Krieger, Axel; Iordachita, Iulian I.; Guion, Peter; Singh, Anurag K.; Kaushal, Aradhana; Ménard, Cynthia; Pinto, Peter A.; Camphausen, Kevin; Fichtinger, Gabor

2012-01-01

This paper reports the development, evaluation, and first clinical trials of the access to the prostate tissue (APT) II system—a scanner independent system for magnetic resonance imaging (MRI)-guided transrectal prostate interventions. The system utilizes novel manipulator mechanics employing a steerable needle channel and a novel six degree-of-freedom hybrid tracking method, comprising passive fiducial tracking for initial registration and subsequent incremental motion measurements. Targeting accuracy of the system in prostate phantom experiments and two clinical human-subject procedures is shown to compare favorably with existing systems using passive and active tracking methods. The portable design of the APT II system, using only standard MRI image sequences and minimal custom scanner interfacing, allows the system to be easily used on different MRI scanners. PMID:22009867

Dynamic analysis, circuit implementation and passive control of a novel four-dimensional chaotic system with multiscroll attractor and multiple coexisting attractors

NASA Astrophysics Data System (ADS)

Lai, Bang-Cheng; He, Jian-Jun

2018-03-01

In this paper, we construct a novel 4D autonomous chaotic system with four cross-product nonlinear terms and five equilibria. The multiple coexisting attractors and the multiscroll attractor of the system are numerically investigated. Research results show that the system has various types of multiple attractors, including three strange attractors with a limit cycle, three limit cycles, two strange attractors with a pair of limit cycles, two coexisting strange attractors. By using the passive control theory, a controller is designed for controlling the chaos of the system. Both analytical and numerical studies verify that the designed controller can suppress chaotic motion and stabilise the system at the origin. Moreover, an electronic circuit is presented for implementing the chaotic system.

Flexibility increases lift on passive fluttering wings

NASA Astrophysics Data System (ADS)

Tam, Daniel; Bush, John

2013-11-01

We examine the influence of flexibility on the side-to-side fluttering motion of passive wings settling under the influence of gravity. This effect is examined through an experimental investigation of deformable rectangular wings falling in a water tank. Our results demonstrate the existence of an optimal flexibility, for which flexible wings remain flying twice longer and hence settle twice slower compared to rigid wings of identical mass and geometry. Flow visualizations and measurements provide key insight to elucidate the role of flexibility in generating increased lift and wing circulation by shedding additional vorticity at the turning point. Theoretical scalings are derived from a reduced model of the flight dynamics in qualitative and quantitative agreement with experiments. These scalings rationalize the strong positive correlation between flexibility and time of flight.

The Role of Organ of Corti Mass in Passive Cochlear Tuning

PubMed Central

de La Rochefoucauld, Ombeline; Olson, Elizabeth S.

2007-01-01

The mechanism for passive cochlear tuning remains unsettled. Early models considered the organ of Corti complex (OCC) as a succession of spring-mass resonators. Later, traveling wave models showed that passive tuning could arise through the interaction of cochlear fluid mass and OCC stiffness without local resonators. However, including enough OCC mass to produce local resonance enhanced the tuning by slowing and thereby growing the traveling wave as it approached its resonant segment. To decide whether the OCC mass plays a role in tuning, the frequency variation of the wavenumber of the cochlear traveling wave was measured (in vivo, passive cochleae) and compared to theoretical predictions. The experimental wavenumber was found by taking the phase difference of basilar membrane motion between two longitudinally spaced locations and dividing by the distance between them. The theoretical wavenumber was a solution of the dispersion relation of a three-dimensional cochlear model with OCC mass and stiffness as the free parameters. The experimental data were only well fit by a model that included OCC mass. However, as the measurement position moved from a best-frequency place of 40 to 12 kHz, the role of mass was diminished. The notion of local resonance seems to only apply in the very high-frequency region of the cochlea. PMID:17905841

Diode-pumped continuous-wave and passively Q-switched Nd:GdLuAG laser at 1443.9 nm

NASA Astrophysics Data System (ADS)

Wu, Qianwen; Liu, Zhaojun; Zhang, Sasa; Cong, Zhenghua; Guan, Chen; Xue, Feng; Chen, Hui; Huang, Qingjie; Xu, Xiaodong; Xu, Jun; Qin, Zengguang

2017-12-01

We investigated the 1443.9 nm laser characteristics of Nd:GdLuAG crystal. Diode-end-pumping configuration was employed under both continuous-wave (CW) and passively Q-switched operations. For CW operation, the maximum average output power was 1.36 W with a slope efficiency of 15%. By using a V3+:YAG crystal as the saturable absorber, we obtained the maximum average output power of 164 mW under Q-switched operation. The corresponding pulse energy was 29.3 μJ and pulse duration was 59 ns.

Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Dong-Jin; Lee, Sun-Kyu, E-mail: skyee@gist.ac.kr

2015-01-15

This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of amore » nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.« less

Towards Unmanned Systems for Dismounted Operations in the Canadian Forces

DTIC Science & Technology

2011-01-01

LIDAR , and RADAR) and lower power/mass, passive imaging techniques such as structure from motion and simultaneous localisation and mapping ( SLAM ...sensors and learning algorithms. 5.1.2 Simultaneous localisation and mapping SLAM algorithms concurrently estimate a robot pose and a map of unique...locations and vehicle pose are part of the SLAM state vector and are estimated in each update step. AISS developed a monocular camera-based SLAM

DURIP: Piezoresponse Force Microscope (PFM) with Controlled Environment for Characterization of Flexoelectric Nanostructures

DTIC Science & Technology

2015-04-21

seismic sensors , acoustic sensors , electromagnetic sensors and infrared (IR) detectors are among in-need multimodal sensing of vehicles, personnel, weapons... sensors and detectors largely due to the fact that the nature of piezoelectricity renders both active and passive sensing with fast response, low profile...and low power consumption. Acoustic and seismic sensors are used to ascertain the exact target location, speed, direction of motion, and

International Workshop on Detection, Classification and Localization of Marine Mammals Using Passive Acoustics (4th). International Workshop on Density Estimation of Marine Mammals Using Passive Acoustics (1st)

DTIC Science & Technology

2009-09-13

University of Singapore) Olivier Adam (NAMC, Univ. of Paris , France) Len Thomas (Univ St Andrews, Scotland; convenor of the DE workshop...Hervé, Paris Sébastien 90 3 - The Continuous Development for Passive Acoustic Monitoring in Offshore Commercial Industry A. Cucknell and N. Clark...encourage researchers to work on a common dataset, to focus on the same problems, to find original solutions, and to present and compare them at the