The physiological cost index of walking with a powered knee ankle foot orthosis in subjects with poliomyelitis : A pilot study

Background: A powered knee ankle foot orthosis (KAFO) was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait. Objectives: The purpose of this study was to determine its effect on the physiological cost index (PCI), walking speed and the distance walked in people with poliomyelitis compared to when walking with a KAFO with drop lock knee joints. Methods: Seven subjects with poliomyelitis volunteered for the study, and undertook gait analysis with both types of KAFO. Results: Walking with the powered KAFO significantly reduced walking speed (p=0.015) and the distance walked (p=0.004), and also it did not improve PCI values (p =0.009) compared to walking with the locked KAFO. Conclusion: Using a powered KAFO did not significantly improve any of the primary outcome measures during walking for poliomyelitis subjects

Large atom number dual-species magneto-optical trap for fermionic 6Li and 40K atoms

We present the design, implementation and characterization of a dual-species magneto-optical trap (MOT) for fermionic 6Li and 40K atoms with large atom numbers. The MOT simultaneously contains 5.2x10^9 6Li-atoms and 8.0x10^9 40K-atoms, which are continuously loaded by a Zeeman slower for 6Li and a 2D-MOT for 40K. The atom sources induce capture rates of 1.2x10^9 6Li-atoms/s and 1.4x10^9 40K-atoms/s. Trap losses due to light-induced interspecies collisions of ~65% were observed and could be minimized to ~10% by using low magnetic field gradients and low light powers in the repumping light of both atomic species. The described system represents the starting point for the production of a large-atom number quantum degenerate Fermi-Fermi mixture

Evaluation of gait symmetry in poliomyelitis subjects : Comparison of a conventional knee ankle foot orthosis (KAFO) and a new powered KAFO.

Background: Compared to able-bodied subjects, subjects with post polio syndrome and poliomyelitis demonstrate a preference for weight-bearing on the non-paretic limb, causing gait asymmetry. Objectives: The purpose of this study was to evaluate the gait symmetry of the poliomyelitis subjects when ambulating with either a drop- locked knee ankle foot orthosis (KAFO) or a newly developed powered KAFO. Methods: Seven subjects with poliomyelitis who routinely wore conventional KAFOs participated in this study, and received training to enable them to ambulate with the powered KAFO on level ground, prior to gait analysis. Results: There were no significant differences in the gait symmetry index (SI) of step length (P=0.085), stance time (P=0.082), double limb support time (P=0.929) or speed of walking (p=0.325) between the two test conditions. However, using the new powered KAFO improved the SI in step width (P=0.037), swing time (P=0.014), stance phase percentage (P=0.008) and knee flexion during swing phase (p≤0.001) compared to wearing the dropped locked KAFO. Conclusion: The use of a powered KAFO for ambulation by poliomyelitis subjects affects gait symmetry in the base of support, swing time, stance phase percentage and knee flexion during swing phase

A Preliminary Study on Robot-Assisted Ankle Rehabilitation for the Treatment of Drop Foot

This paper involves the use of a compliant ankle rehabilitation robot (CARR) for the treatment of drop foot. The robot has a bio-inspired design by employing four Festo Fluidic muscles (FFMs) that mimic skeletal muscles actuating three rotational degrees of freedom (DOFs). A trajectory tracking controller was developed in joint task space to track the predefined trajectory of the end effector. This controller was achieved by controlling individual FFM length based on inverse kinematics. Three patients with drop foot participated in a preliminary study to evaluate the potential of the CARR for clinical applications. Ankle stretching exercises along ankle dorsiflexion and plantarflexion (DP) were delivered for treating drop foot. All patients gave positive feedback in using this ankle robot for the treatment of drop foot, although some limitations exist. The proposed controller showed satisfactory accuracy in trajectory tracking, with all root mean square deviation (RMSD) values no greater than 0.0335 rad and normalized root mean square deviation (NRMSD) values less than 6.7%. These preliminary findings support the potentials of the CARR for clinical applications. Future work will investigate the effectiveness of the robot for treating drop foot on a large sample of subjects

The influence of a powered knee-ankle-foot orthosis on walking in poliomyelitis subjects: A pilot study

Background: Traditionally, the anatomical knee joint is locked in extension when walking with a conventional knee-ankle-foot orthosis. A powered knee-ankle-foot orthosis was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait. Objective: The purpose of this study was to determine differences of the powered knee-ankle-foot orthosis compared to a locked knee-ankle-foot orthosis in kinematic data and temporospatial parameters during ambulation. Study design: Quasi-experimental design. Methods: Subjects with poliomyelitis (n = 7) volunteered for this study and undertook gait analysis with both the powered and the conventional knee-ankle-foot orthoses. Three trials per orthosis were collected while each subject walked along a 6-m walkway using a calibrated six-camera three-dimensional video-based motion analysis system. Results: Walking with the powered knee-ankle-foot orthosis resulted in a significant reduction in both walking speed and step length (both 18%), but a significant increase in stance phase percentage compared to walking with the conventional knee-ankle-foot orthosis. Cadence was not significantly different between the two test conditions (p = 0.751). There was significantly higher knee flexion during swing phase and increased hip hiking when using the powered orthosis. Conclusion: The new powered orthosis permitted improved knee joint kinematic for knee-ankle-foot orthosis users while providing knee support in stance and active knee motion in swing in the gait cycle. Therefore, the new powered orthosis provided more natural knee flexion during swing for orthosis users compared to the locked knee-ankle-foot orthosis

Why Tolerate Religion?

Proceedings of the 9th International Multidisciplinary Conference «Stress and Behavior» Saint-Petersburg, Russia, 16–19 May 2005.Impaired wakefulness in machine operators represents a danger for both themselves and the general public. While on duty, such persons are expected to be continuously, i.e., without interruption, on the alert. For this, we have designed experimental model of continuous vigilance monitoring using electroencephalography (EEG) and reaction time.Method: The long lasting experiments took place at nighttime (22.00–05.00 h) on 6 young adult men (18–26 years) in 5 separate experiments (30 experiments). The participants were half-lying in an armchair in a darken room with open eyes and underwent psychomotor vigilance test (pressing the button of joystick the right or left hand). After a green-light flash, participants pressed the button by right hand, and after a red-light flash, they had to press button with the left hand. Inter-stimuli intervals varied from 2 to 4 s. The probability of occurrence was 70 % (green flash) and 30 % (red flash). For activity support during all night, the participants were allowed to have a break 4–5 times for 10–15 minutes. For data registration, we used digital 54-channel polygraph «SAGURA-2000» (MKE Medizintechnik GmbH, Germany). We registered: 6 channels of EEG (F3, F4, C3, C4, O1, 02), EOG (horizontal and vertical movements of eyes) and polygraphical parameters: EDR, ECG, EMG, breathing, SpO2, pressing buttons and the video-image of the subjects.Data analyses. Reaction time varied rather widely, between 200 and 1000 ms. EEG power (FFT) in 6 standard EEG-ranges, for 5 s artifact free epoch was measured.Results: At lengthening time of the reaction and error appearance, caused by development of a drowsy condition, the most indicative changes were observed in an alpha and theta/delta — ranges of EEG. The direction of changes EEG was similar in all subjects: at decrease of a level of wakefulness, the EEG power in an alpha and theta/delta ranges markedly increased. Importantly, the individual differences in character of these changes have to be taken into account while creating monitoring systems to control the level of wakefulness

Climate-driven shifts in sediment chemistry enhance methane production in northern lakes

Freshwater ecosystems are a major source of methane (CH4), contributing 0.65 Pg (in CO2 equivalents) yr−1 towards global carbon emissions and offsetting ~25% of the terrestrial carbon sink. Most freshwater CH4 emissions come from littoral sediments, where large quantities of plant material are decomposed. Climate change is predicted to shift plant community composition, and thus change the quality of inputs into detrital food webs, with the potential to affect CH4 production. Here we find that variation in phenol availability from decomposing organic matter underlies large differences in CH4 production in lake sediments. Production is at least 400-times higher from sediments composed of macrophyte litter compared to terrestrial sources because of inhibition of methanogenesis by phenol leachates. Our results now suggest that earth system models and carbon budgets should consider the effects of plant communities on sediment chemistry and ultimately CH4 emissions at a global scale