Passive Manipulation Research Articles

PF.23 Medium Term Childhood Outcome of Isolated Congenital Talipes Equinovarus Diagnosed Antenatally

Congenital talipes equinovarus (CTEV) is one of the most common developmental abnormalities affecting the lower limb. It may be associated with a variety of disorders and can be diagnosed antenatally...

Somatosensory responses in a human motor cortex

Somatic sensory signals provide a major source of feedback to motor cortex. Changes in somatosensory systems after stroke or injury could profoundly influence brain computer interfaces (BCI) being developed to create new output signals from motor cortex activity patterns. We had the unique opportunity to study the responses of hand/arm area neurons in primary motor cortex to passive joint manipulation in a person with a long-standing brain stem stroke but intact sensory pathways. Neurons responded to passive manipulation of the contralateral shoulder, elbow, or wrist as predicted from prior studies of intact primates. Thus fundamental properties and organization were preserved despite arm/hand paralysis and damage to cortical outputs. The same neurons were engaged by attempted arm actions. These results indicate that intact sensory pathways retain the potential to influence primary motor cortex firing rates years after cortical outputs are interrupted and may contribute to online decoding of motor intentions for BCI applications.

Physiological and growth responses of switchgrass (Panicum virgatumL.) in native stands under passive air temperature manipulation

AbstractIn the centralGreatPlains ofNorthAmerica, climate change predictions include increases in mean annual temperature of 1.5–5.5 °C by 2100. Ecosystem responses to increased temperatures are likely to be regulated by dominant plant species, such as the potential biofuel speciesPanicum virgatum(switchgrass) in the tallgrass prairie. To describe the potential physiological and whole‐plant responses of this species to future changes in air temperatures, we used louvered open‐sided chambers (louveredOSC; 1 × 1 m, adjustable height) to passively alter canopy temperature in native stands ofP. virgatumgrowing in tallgrass prairie at varying topographic positions (upland/lowland). The altered temperature treatment decreased daily mean temperatures by 1 °C and maximum temperatures by 4 °C inMay andJune, lowered daytime stomatal conductance and transpiration, decreased tiller density, increased specific leaf area, and delayed flowering. Among topographic contrasts, aboveground biomass, flowering tiller density, and tiller weight were greater in lowland sites compared to upland sites, with no temperature treatment interactions. Differences in biomass production responded more to topography than the altered temperature treatment, as soil water status varied considerably between topographic positions. These results indicate that while water availability as a function of topography was a strong driver of plant biomass, many leaf‐level physiological processes were responsive to the small decreases in daily mean and maximum temperature, irrespective of landscape position. The varying responses of leaf‐level gas exchange and whole‐plant growth ofP. virgatumin native stands to altered air temperature or topographic position illustrate that accurately forecasting yields forP. virgatumin mixed communities will require greater integration of physiological responses to simulated climate change (increased temperature) and resource availability over natural environmental gradients (soil moisture).

Passive Soil Manipulation Influences the Successional Trajectories of Forest Communities at a Denuded Former Campsite

Passive Soil Manipulation Influences the Successional Trajectories of Forest Communities at a Denuded Former Campsite

The contribution of vision, proprioception, and efference copy in storing a neural representation for guiding trail leg trajectory over an obstacle

Stepping over obstacles requires vision to guide the leading leg, but direct visual information is not available to guide the trailing leg. The neural mechanisms for establishing a stored obstacle representation and thus facilitating the trail leg trajectory in humans are unknown. Twenty-four subjects participated in one of three experiments, which were designed to investigate the contribution of visual, proprioceptive, and efference copy signals. Subjects stepped over an obstacle with their lead leg, stopped, and straddled the obstacle for a delay period before stepping over it with their trail leg while toe elevation was recorded. Subsequently, we calculated maximum toe elevation and toe clearance. First, we found that subjects could accurately scale trail leg toe elevation and clearance, despite straddling an obstacle for up to 2 min, similar to quadrupeds. Second, we found that when the lead leg was passively moved over an obstacle (eliminating an efference copy signal and altering proprioception) without vision, trail leg toe elevation and clearance were reduced, and variability increased compared with when subjects actively moved their lead leg. Trail leg toe measures returned to normal when vision was provided during the passive manipulation. Finally, we found that altering lead leg proprioceptive feedback by adding mass to the ankle had no effect on trail leg toe measures. Taken together, our results suggest that humans can store a neural representation of obstacle properties for extended periods of time and that vision appears to be sufficient in this process to guide trail leg trajectory.

Automation Highlights from the Literature

Automation Highlights from the Literature

Quasi-steady capillarity-driven flows in slender containers with interior edges

AbstractIn the absence of significant body forces the passive manipulation of fluid interfacial flows is naturally achieved by control of the specific geometry and wetting properties of the system. Numerous ‘microfluidic’ systems on Earth and ‘macrofluidic’ systems aboard spacecraft routinely exploit such methods and the term ‘capillary fluidics’ is used to describe both length-scale limits. In this work a collection of analytic solutions is offered for passive and weakly forced flows where a bulk capillary liquid is slowly drained or supplied by a faster capillary flow along at least one interior edge of the container. The solutions are enabled by an assumed known pressure (or known height) dynamical boundary condition. Following a series of assumptions this boundary condition can be in part determined a priori from the container dimensions and further quantitative experimental evidence, but not proof, is provided in support of its expanded use herein. In general, a small parameter arises in the scaling of the problems permitting a decoupling of the edge flow from the global bulk meniscus flow. The quasi-steady asymptotic system of equations that results may then be easily solved in closed form for a useful variety of geometries including uniform and tapered sections possessing at least one critically wetted interior edge. Draining, filling, bubble displacement and other imbibing flows are studied. Cursory terrestrial and drop tower experiments agree well with the solutions. The solutions are valued for the facility they provide in computing designs for selected capillary fluidics problems by way of passive transport rates and meniscus displacement. Because geometric permutations of any given design are myriad, such analytic tools are capable of efficiently identifying and comparing critical design criteria (i.e. shape and size) and the impact of various wetting conditions resulting from the fluid properties and surface conditions. Sample optimizations are performed to demonstrate the utility of the method.

Passive Dynamic Object Manipulation: Preliminary Definition and Examples

摘要: In this work, we introduce a category of dynamic manipulation processes, namely passive dynamic object manipulation, according to which an object is manipulated passively. Specifically, we study passive dynamic manipulation here. We define the main concept, discuss the challenges, and talk about the future directions. Like other passive robotic systems, there are no actuators in these systems. The object follows a path and travels along it under the effect of its own weight, as well as the interaction force applied by each manipulator on it. We select some simple examples to show the concept. For each example, dynamic equations of motion are derived and the stability of the process is taken into account. In this direction, some rules are derived under which we ensure that the manipulation process does not fail. Simulations support this idea. 关键词: Passive systems / dynamic manipulation / passive manipulation / robotic system

Passive Dynamic Object Manipulation: Preliminary Definition and Examples

In this work, we introduce a category of dynamic manipulation processes, namely passive dynamic object manipulation, according to which an object is manipulated passively. Specifically, we study passive dynamic manipulation here. We define the main concept, discuss the challenges, and talk about the future directions. Like other passive robotic systems, there are no actuators in these systems. The object follows a path and travels along it under the effect of its own weight, as well as the interaction force applied by each manipulator on it. We select some simple examples to show the concept. For each example, dynamic equations of motion are derived and the stability of the process is taken into account. In this direction, some rules are derived under which we ensure that the manipulation process does not fail. Simulations support this idea.

Evaluation of the effectiveness of a phonoaudiology program for the rehabilitation of dysphagia in the elderly

The object of this study was to evaluate the effectiveness of a phonoaudiology rehabilitation program directed towards the degenerative changes of the neurophysiological mechanisms responsible for the upper digestive system compromised by the age between 80 and 90 years, in a regime of internment in a long permanence institution in the city of Rio de Janeiro, which express, bodily, their difficulty in swallowing food of liquid or pasty consistency. To achieve such an object, the current study was developed in an experimental format or design, comprised of a sample group of 23 elderly subjects, of both genders, undergoing evaluation by the phonoaudiology protocol for evaluating the risk of dysphagia (abbreviated from the Portuguese name: Protocolo de Avaliação do Risco para Disfagia = PARD), pre- and post-intervention procedure. The developed program used the indirect therapy approach based on the adaptive myotherapeutic and myofunctional stimulation, contemplating two isometric and isokinetic orofacial active myotherapeutic exercises, two passive myotherapeutic manipulations for the supra-hyoidal musculature, as well as adaptive cephalic postural maneuvres, associated to the intra-oral olfactive and gustative sensory stimulation. The evolution of the individuals was analyzed before and after the therapy by estimating the capacity of swallowing food in the liquid fluid (LF) consistency, by the paired Student t-test, giving a p = 0.01, making the difference of 2.31 between the 2 evaluations statistically significant. The changes produced by the PARD program in the capacity of individuals in swallowing food of a pasty consistency were also significant when analyzing the variance of the results on the 2 instances by using the F-test (pre- and post-intervention difference = 4.47, p = 0.039).

Intermuscular force transmission between human plantarflexor muscles in vivo

The exact mechanical function of synergist muscles within a human limb in vivo is not well described. Recent studies indicate the existence of a mechanical interaction between muscle actuators that may have functional significance and further play a role for injury mechanisms. The purpose of the present study was to investigate if intermuscular force transmission occurs within and between human plantarflexor muscles in vivo. Seven subjects performed four types of either active contractile tasks or passive joint manipulations: passive knee extension, voluntary isometric plantarflexion, voluntary isometric hallux flexion, passive hallux extension, and selective percutaneous stimulation of the gastrocnemius medialis (MG). In each experiment plantar- and hallux flexion force and corresponding EMG activity were sampled. During all tasks ultrasonography was applied at proximal and distal sites to assess task-induced tissue displacement (which is assumed to represent loading) for the plantarflexor muscles [MG, soleus (SOL), and flexor hallucis longus (FHL)]. Selective MG stimulation and passive knee extension resulted in displacement of both the MG and SOL muscles. Minimal displacement of the triceps surae muscles was seen during passive hallux extension. Large interindividual differences with respect to deep plantarflexor activation during voluntary contractions were observed. The present results suggest that force may be transmitted between the triceps surae muscles in vivo, while only limited evidence was provided for the occurrence of force transfer between the triceps surae and the deeper-lying FHL.

Talar Callosity in Children—What, Who, Why?

Figure 2. The foot with the larger callosity is the one drawn closer to the body in cross-legged sitting. T he talar callosity is a relatively uncommon ankle lump in children. Although asymptomatic and entirely ‘‘benign,’’ it is a major cause of parental concern. Clinically, the talar callosity refers to an area of hyperkeratotic skin on the anterolateral aspect of the ankle. Talar callosities are typically 2.0 to 2.5 cm in diameter, may be unilateral or bilateral, and are usually a shade darker than the surrounding skin (Figure 1). They can be associatedwith smaller callosities over the ipsilateral lateral malleolus, fifth metatarsal base or head, or other bony prominence in the foot. For 5 years, 26 children at our institution had talar callosities. There were 17 boys (65.4%) and 9 girls (34.6%) between 3 and 8 years of age (mean age, 5.3 years). All 26 children had generalized ligament laxity and a preference for cross-legged sitting without shoes. Sixteen children (61.5%) had bilateral callosities. The 10 children (38.5%) with unilateral involvement consistently sat cross-legged so that the ankle with the callosity (Figure 2) was the one drawn closer to the body and bore the additional weight of the contralateral thigh. It was also the side on which there was greater hindfoot equinovarus and forefoot adductus and supination, thrusting the anterolateral aspect of the talar head into prominence. This position of the foot in a crosslegged sitting position can be readily simulated with passive manipulation; in our experience, this simple demonstration greatly facilitates parents’ understanding of the condition. The families of 19 children were satisfied with simple reassurance on the basis of clinical evaluation. At the

Open Mouth Digital Reduction of an Odontoid Synchondrosis Fracture

The "odontoid synchondrosis fracture" represents a rare but typical injury of the upper cervical spine in children less than 7 years. Conservative treatment with closed reduction and external fixation shows fusion rates across the synchondrosis in about 90% cases. When closed reduction cannot be achieved, open reduction and internal fixation is usually performed. We present the case of a girl aged 3 years and 5 months, whose closed reduction by passive manipulation of the head failed, but the same could successfully be achieved through transoral manipulation of the dens. After treatment with a Minerva plaster cast, the fracture was healed without complication. We suggest transoral manipulation in cases of otherwise irreducible "odontoid synchondrosis fracture." This technical hint may avoid unnecessary surgery in children with this type of injury.

Streaming and mixing induced by a bundle of ciliary vibrating micro-pillars

Directional near-wall flow induced by the vibration of slender micro-pillars attached to a surface similar to ciliary structures or grafted filaments is studied experimentally. The micro-pillar arrays are arranged in the form of a “V” approximating an asymmetric fore-aft bundle shape often found in nature, too. A base-layer actuation is used to excite the micro-pillars to oscillate in a vibratory pattern with maximum amplitude at the tips. Due to the specific shape of the bundle structure and asymmetric boundary conditions of the oscillatory motion, the pillars perform a tilted beating motion—similar to cilia—with a forward power stroke and a backward oriented recovery stroke or vice versa, depending on the boundary conditions of the actuation. As a consequence of the cooperative beating motion and the fore-aft asymmetry of the shape of the bundle, a directional streaming motion is induced by the pillars which increase with increasing streaming Reynolds number Re S . In addition to the net streaming effect, the flow in the space between the pillar bases exhibit a micro-scale swirling motion around each of the structures with an efficient mixing behavior. Applied to micro-channels or wall-bounded flows, such structures may act as locally distributed passive or active flow manipulation devices. The use of such cilia bundles in large numbers on surfaces as passive structures for near-wall control in of boundary layer flows is feasible, too.

The stiff elbow.

Elbow motion is essential for upper extremity function to position the hand in space. Unfortunately, the elbow joint is prone to stiffness following a multitude of traumatic and atraumatic etiologies. Elbow stiffness can be diagnosed with a complete history and physical exam, supplemented with appropriate imaging studies. The stiff elbow is challenging to treat, and thus, its prevention is of paramount importance. When this approach fails, non-operative followed by operative treatment modalities should be pursued. Upon initial presentation in those who have minimal contractures of 6-month duration or less, static and dynamic splinting, serial casting, continuous passive motion, occupational/physical therapy, and manipulation are non-operative treatment modalities that may be attempted. A stiff elbow that is refractory to non-operative management can be treated surgically, either arthroscopically or open, to eliminate soft tissue or bony blocks to motion. In the future, efforts to prevent and treat elbow stiffness may target the basic science mechanisms involved. Our purpose was to review the etiologies, classification, evaluation, prevention, operative, and non-operative treatment of the stiff elbow.

Active Manipulation of Quantum Dots using AC Electrokinetics

The superior optical and electrical properties of quantum dot (QD) nanoparticles are being applied in a new generation of QD devices for microelectronic, nanophotonic, and biomedical systems. Research on integrated QD-based systems has been focused on passive manipulation of QDs including template-guided self-assembly, molecular scaffold-based assembly, and microbead-based assembly. However, little effort has been devoted to development of methods for active manipulation, such as positioning and concentration, of QDs. In this study, we show that 20 nm colloidal QDs can be effectively positioned and concentrated using a combination of dielectrophoresis (DEP) and AC electro-osmosis (ACEO). The long-range fluid motion generated by ACEO entrains QDs to the area near the electrode surface, which facilitates the trapping of QDs by DEP. A systematic investigation was performed to examine electrokinetic processes at different applied frequencies and voltages using a concentric electrode configuration. We demonstrate that QDs can be dynamically positioned with an electric field strength as small as 10 kV/m and define the operating parameters for increasing the concentration of colloidal QDs by 2 orders of magnitude within one minute.

Passive Manipulation of Separation-Bubble Transition Using Surface Modifications

Through experiments using two-dimensional particle-image velocimetry (PIV), this paper examines the nature of transition in a separation bubble and manipulations of the resultant breakdown to turbulence through passive means of control. An airfoil was used that provides minimal variation in the separation location over a wide operating range, with various two-dimensional modifications made to the surface for the purpose of manipulating the transition process. The study was conducted under low-freestream-turbulence conditions over a flow Reynolds number range of 28,000–101,000 based on airfoil chord. The spatial nature of the measurements has allowed identification of the dominant flow structures associated with transition in the separated shear layer and the manipulations introduced by the surface modifications. The Kelvin–Helmholtz (K-H) instability is identified as the dominant transition mechanism in the separated shear layer, leading to the roll-up of spanwise vorticity and subsequent breakdown into small-scale turbulence. Similarities with planar free-shear layers are noted, including the frequency of maximum amplification rate for the K-H instability and the vortex-pairing phenomenon initiated by a subharmonic instability. In some cases, secondary pairing events are observed and result in a laminar intervortex region consisting of freestream fluid entrained toward the surface due to the strong circulation of the large-scale vortices. Results of the surface-modification study show that different physical mechanisms can be manipulated to affect the separation, transition, and reattachment processes over the airfoil. These manipulations are also shown to affect the boundary-layer losses observed downstream of reattachment, with all surface-indentation configurations providing decreased losses at the three lowest Reynolds numbers and three of the five configurations providing decreased losses at the highest Reynolds number. The primary mechanisms that provide these manipulations include: suppression of the vortex-pairing phenomenon, which reduces both the shear-layer thickness and the levels of small-scale turbulence; the promotion of smaller-scale turbulence, resulting from the disturbances generated upstream of separation, which provides quicker transition and shorter separation bubbles; the elimination of the separation bubble with transition occurring in an attached boundary layer; and physical disturbance, downstream of separation, of the growing instability waves to manipulate the vortical structures and cause quicker reattachment.

Conformal switchable superhydrophobic/hydrophilic surfaces for microscale flow control

The development of microvalves is essential to realize a fully integrated system for nano/microliter fluid handling in microfluidic devices. Microvalves that utilize passive fluidic manipulation employ a hydrophobic surface in a microchannel network in which the operation is controlled by the interfacial tension of the liquid–air–solid interface. In order to obtain a switchable valve in microfluidic channels, conformal hydrophobic/hydrophilic and superhydrophobic/hydrophilic thermal switchable surfaces were fabricated by the layer-by-layer deposition of poly(allylamine hydrochloride) (PAH) and silica nanoparticles followed by the functionalization of a thermosensitive polymer-poly( N-isopropylacrylamide) (PNIPAAm) and perfluorosilane. A fully integrated microfluidic valve using a thermal switchable superhydrophobic/hydrophilic polymer patch has been fabricated. At 70 °C, the valve is superhydrophobic and stops the water flow (closing status) while at room temperature, the patch becomes hydrophilic, and allows the flow (opening status).

An Unusual Case of Elbow Dislocation

The annual incidence of elbow dislocation is 6 to 8 cases per 100,000 in the United States; these dislocations represent 11% to 28% of all elbow injuries. The frequency of elbow dislocation is second to that of shoulder dislocation. Adult elbow dislocations are classified by the direction of displacement and associated fractures. They can be anterior, posterior, lateral, or divergent, with the most common type being posterior displacement of both the radius and ulna in relation to the distal humerus. This case report presents a rare case of a twisting dislocation of the elbow joint without any accompanying fracture. A 55-year-old woman presented with a swollen and painful right elbow joint and a pronated forearm after falling on her outstretched right arm. Closed reduction was performed under local anesthetic. No neurovascular deficit was recorded before or after reduction, and no ectopic calcification was observed at 1 year follow-up. Early mobilization of the elbow resulted in a stable joint with full range of motion. The rehabilitation of elbow dislocation ranges from aggressive immediate active motion to traditional plaster of Paris immobilization for several days. Forceful passive mobilization in the rehabilitation period must be avoided, since the elbow joint has a natural tendency to develop myositis ossificans following passive manipulation.

In vivo measurement of 3-dimensional movement of the iliosacral joint

The purpose of this study was to quantify in vivo the three-dimensional motion patterns of the sacroiliac joint during passive manipulations as the opinions about the extent of motion of this joint are varied. 12 sacroiliac joints of 6 patients with clinically and radiologically normal joints were investigated. All patients were treated with an external fixator for diagnostic purposes of low back pain unrelated of this study. The motion of the sacroiliac joint was measured continuously with a three-dimensional goniometric system, which was mounted at the end of Schanz screws implanted in S1 and the ilium. All measurements showed relatively small rotation angles around the three main axis to the body between the ilium and the sacrum (< 2 degrees) and very small translations between the screw entry points into the bones (< 1 mm). The maximum rotation angle in the sagittal plane was 1.3 degrees on the right joint and 1.6 degrees on the left joint for flexion plus extension. It is questionable whether this motion can be quantified during manual manipulation. Extension of the hip always produced the largest motion in the sacroiliac joint.