Novel swing-assist un-motorized exoskeletons for gait training

<p>Abstract</p> <p>Background</p> <p>Robotics is emerging as a promising tool for functional training of human movement. Much of the research in this area over the last decade has focused on upper extremity orthotic devices. Some recent commercial designs proposed for the lower extremity are powered and expensive – hence, these could have limited affordability by most clinics. In this paper, we present a novel un-motorized bilateral exoskeleton that can be used to assist in treadmill training of motor-impaired patients, such as with motor-incomplete spinal cord injury. The exoskeleton is designed such that the human leg will have a desirable swing motion, once it is strapped to the exoskeleton. Since this exoskeleton is un-motorized, it can potentially be produced cheaply and could reduce the physical demand on therapists during treadmill training.</p> <p>Results</p> <p>A swing-assist bilateral exoskeleton was designed and fabricated at the University of Delaware having the following salient features: (i) The design uses torsional springs at the hip and the knee joints to assist the swing motion. The springs get charged by the treadmill during stance phase of the leg and provide propulsion forces to the leg during swing. (ii) The design of the exoskeleton uses simple dynamic models of sagittal plane walking, which are used to optimize the parameters of the springs so that the foot can clear the ground and have a desirable forward motion during walking. The bilateral exoskeleton was tested on a healthy subject during treadmill walking for a range of walking speeds between 1.0 mph and 4.0 mph. Joint encoders and interface force-torque sensors mounted on the exoskeleton were used to evaluate the effectiveness of the exoskeleton in terms of the hip and knee joint torques applied by the human during treadmill walking.</p> <p>Conclusion</p> <p>We compared two different cases. In case 1, we estimated the torque applied by the human joints when walking with the device using the joint kinematic data and interface force-torque sensors. In case 2, we calculated the required torque to perform a similar gait only using the kinematic data collected from joint motion sensors. On analysis, we found that at 2.0 mph, the device was effective in reducing the maximum hip torque requirement and the knee joint torque during the beginning of the swing. These behaviors were retained as the treadmill speed was changed between 1–4 mph. These results were remarkable considering the simplicity of the dynamic model, model uncertainty, non-ideal spring behavior, and friction in the joints. We believe that the results can be further improved in the future. Nevertheless, this promises to provide a useful and effective methodolgy for design of un-motorized exoskeletons to assist and train swing of motor-impaired patients.</p

Mucoadhesive microcapsules of glipizide formulated with gum kondagogu: in vitro and in vivo evaluation

Mucoadhesive microcapsules are proposed for the antidiabetic drug glipizide, to obtain controlled release. Glipizide microcapsules with a coat consisting of alginate and gum kondagogu were prepared by employing ionic gelation process and emulsification ionotropic gelation process. The microcapsules were evaluated for flow properties, Carr’s index, Hausner factor, microencapsulation efficiency, drug release characteristics, surface characteristics, compatibility studies, mucoadhesive properties and in-vivo hypoglycemic activity. These two methods showed individual, large sized, free flowing spherical microcapsules without any interactions. Glipizide release from the microcapsules was slow and followed zero order kinetics and followed non–fickian release and depended on the coat: core ratio and the method employed in the preparation of microcapsules. Among the two methods emulsification ionotropic gelation method was found to be more suitable for slow and complete release of glipizide over a long period of time. These microcapsules exhibited good mucoadhesive property in the in vitro wash-off test. In vivo evaluation in rabbits demonstrated significant hypoglycemic effect of glipizide.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Innovative gait robot for the repetitive practice of floor walking and stair climbing up and down in stroke patients

<p>Abstract</p> <p>Background</p> <p>Stair climbing up and down is an essential part of everyday's mobility. To enable wheelchair-dependent patients the repetitive practice of this task, a novel gait robot, G-EO-Systems (EO, Lat: I walk), based on the end-effector principle, has been designed. The trajectories of the foot plates are freely programmable enabling not only the practice of simulated floor walking but also stair climbing up and down. The article intended to compare lower limb muscle activation patterns of hemiparetic subjects during real floor walking and stairs climbing up, and during the corresponding simulated conditions on the machine, and secondly to demonstrate gait improvement on single case after training on the machine.</p> <p>Methods</p> <p>The muscle activation pattern of seven lower limb muscles of six hemiparetic patients during free and simulated walking on the floor and stair climbing was measured via dynamic electromyography. A non-ambulatory, sub-acute stroke patient additionally trained on the G-EO-Systems every workday for five weeks.</p> <p>Results</p> <p>The muscle activation patterns were comparable during the real and simulated conditions, both on the floor and during stair climbing up. Minor differences, concerning the real and simulated floor walking conditions, were a delayed (prolonged) onset (duration) of the thigh muscle activation on the machine across all subjects. Concerning stair climbing conditions, the shank muscle activation was more phasic and timely correct in selected patients on the device. The severely affected subject regained walking and stair climbing ability.</p> <p>Conclusions</p> <p>The G-EO-Systems is an interesting new option in gait rehabilitation after stroke. The lower limb muscle activation patterns were comparable, a training thus feasible, and the positive case report warrants further clinical studies.</p

Passive swing assistive exoskeletons for motor-incomplete spinal cord injury patients

Abstract-In this paper, we present a passive device for swing assistance of motor-incomplete spinal cord injury patients. This device is aimed at reducing the physical demands on the therapists during treadmill training. We model the human leg as two links and a point foot mass, with a moving trunk. We employ passive elements in the design which get charged by the treadmill. Using the system dynamics, we optimize the design parameters to obtain a feasible swing motion of the leg. An exoskeleton was constructed based on these design parameters and tests were performed on a healthy subject at different treadmill speeds

Nanoemulsion based Hydrogels of Itraconazole for Transdermal Drug Delivery

88-92The present study aimed to formulate a nanoemulsion and nanoemulsion based hydrogel of itraconazole for transdermal delivery in the treatment of on chomycosis. The nanoemulsions were prepared using lecithin and sodium cholate as surfactant and co-surfactant. The prepared nanoemulsions were characterized for particle size and zeta potential. The optimized nanoemulsion was incorporated into 3% carbopol-934 solution to get a gel for improving convenience in superficial application. In vitro and <i style="mso-bidi-font-style: normal">ex vivo drug penetration studies of nanoemulsions and gels were determined using dialysis membrane and rat skin. The particle size was found around 223.9 nm to 154.3 nm. The viscosity of the nanoemulsions and nanoemulsion gel were found around 1964.89 mPa.S to 1644.82 mPa.S and 28.3 mPa.S to 8.58 mPa.S respectively. The polydispersibility value was found very low indicating uniformity of droplet size of the formulations. The drug content in gels was found in between 86.2% to 98.26%. The drug release was found to be 44.33 % to 73.6% after 24 h with permeation flux around 296.3 to 203.1 (μg/cm2/hr1). The results indicated that nanoemulsion based hydrogels as promising vehicle for transdermal delivery of itraconazole. Further in vivo studies are to be performed to access its suitability for topical application

Chemical modifications of dehydrocostus lactone from Saussurea lappa and the study of structure-activity relationship

847-851Various chemical analogues of dehydrocostus lactone have been prepared by using various chemo- and regio-selective reagents. The biological activity of the products as plant growth regulators has revealed that the extension of carbon chain length at C₁₃ to a limited extent has marked effect on biological activity