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Passive descent

Steven Culver, Harrison Bartlett, Amanda Shultz, Michael Goldfarb
This paper presents a control system for a powered transtibial prosthesis that provides stair ascent and descent capability, as well as ability for user-controlled transitions between walking, standing, stair ascent, and stair descent. The control system was implemented on a powered prosthesis and evaluated on a single unilateral transtibial amputee subject. The ability of the prosthesis to provide appropriate functionality during stair ascent and descent was assessed by comparing gait kinematics and kinetics of the prosthesis to those of a passive dynamic elastic response prosthesis and those of a set of non-amputee subjects...
May 2018: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Philippe Lherminier
We distinguish two types of predations: the predation of matter-energy equals the food chain, and the informative predation is the capture of the information brought by the sexual partners. The cell or parent consumes energy and matter to grow, multiply and produce offspring. A fixed amount of resources is divided by the number of organisms, so individual growth and numerical multiplication are limited by depletion resources of the environment. Inversely, fertilization does not destroy information, but instead produces news...
March 29, 2018: Comptes Rendus Biologies
I Minagawa, Y Murata, K Terada, M Shibata, E Y Park, H Sasada, T Kohsaka
Insulin-like factor 3 (INSL3), previously called relaxin-like factor, is essential for foetal testis descent and has been implicated in sperm production in adult males. This study investigated the role of INSL3 in sperm production by examining the effect of neutralising INSL3 by passive immunisation on testicular function and sperm output in boars. Six male Duroc boars were randomly assigned to passive immunisation and control groups (n = 3 each). The immunisation group was intravenously injected with an IgG fraction of anti-INSL3 antibody developed against the B domain of INSL3 at 2-week intervals from 21-40 weeks of age...
March 25, 2018: Andrologia
Louis L Flynn, Joost Geeroms, Tom van der Hoeven, Bram Vanderborght, Dirk Lefeber
BACKGROUND: Here we present how the CYBERLEGs Beta-Prosthesis was modified with a new control system to participate in the Powered Leg Prosthesis event, and to report on our experience at the CYBATHLON 2016 which was held in Zurich, Switzerland in October 2016. The prosthesis has two active degrees of freedom which assist the user with extra joint power at the knee and ankle to complete tasks. The CYBATHLON is a championship for people with disabilities competing in six disciplines, using advanced assistive devices...
January 3, 2018: Journal of Neuroengineering and Rehabilitation
Max K Shepherd, Elliott J Rouse
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...
December 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Yun Seong Song, Sehoon Ha, Hsiang Hsu, Lena H Ting, C Karen Liu
Here we show that novel, energy-recycling stairs reduce the amount of work required for humans to both ascend and descend stairs. Our low-power, interactive, and modular steps can be placed on existing staircases, storing energy during stair descent and returning that energy to the user during stair ascent. Energy is recycled through event-triggered latching and unlatching of passive springs without the use of powered actuators. When ascending the energy-recycling stairs, naive users generated 17.4 ± 6.9% less positive work with their leading legs compared to conventional stairs, with the knee joint positive work reduced by 37...
2017: PloS One
Carol Morcos, Aaron B Caughey
OBJECTIVE: To compare the length of the second stage in nulliparous women with respect to a range of factors related to staffing and outcomes at a community hospital. METHODS: This was a retrospective cohort study of nulliparous women presenting for delivery over a 2-year period. The primary outcomes were the presence of passive descent and length of the second stage. Secondary outcomes were mode of delivery, chorioamnionitis, and postpartum hemorrhage. RESULTS: Passive descent was observed in 198 women in the second stage...
June 28, 2017: Journal of Maternal-fetal & Neonatal Medicine
Marie-Pierre Cyr, Jennifer Kruger, Vivien Wong, Chantale Dumoulin, Isabelle Girard, Mélanie Morin
BACKGROUND: Pelvic floor muscles are subject to considerable stretching during vaginal birth. In 13-36% of women, stretching results in avulsion injury whereby the puborectalis muscle disconnects from its insertion points on the pubis bone. Until now, few studies have investigated the effect of this lesion on pelvic floor muscles in the early postpartum period. OBJECTIVE: The primary aim of this study was to compare pelvic floor muscle morphometry and function in primiparous women with and without puborectalis avulsion in the early postpartum period...
March 2017: American Journal of Obstetrics and Gynecology
Bin Lyu, Zhen Yang, Guan Gui, Youhong Feng
This paper considers a backscatter communication (BackCom) system including a reader and N tags, where each tag receives excitation signals transmitted by the reader and concurrently backscatters information to the reader in time-division-multiple-access (TDMA) mode. In this system, we aim to maximize the total system goodput by jointly optimizing reader transmission power, time allocation, and reflection ratio for the cases of passive and semi-passive tags. For each case, an optimization problem is formulated, which is non-convex and can be solved by being decomposed into at most N feasible sub-problems based on the priority of allocated reader transmission power...
November 29, 2016: Sensors
S H Hosseini Nasab, Renate List, Katja Oberhofer, Sandro F Fucentese, Jess G Snedeker, William R Taylor
BACKGROUND: The posterior cruciate ligament (PCL) is the strongest ligament of the knee, serving as one of the major passive stabilizers of the tibio-femoral joint. However, despite a number of experimental and modelling approaches to understand the kinematics and kinetics of the ligament, the normal loading conditions of the PCL and its functional bundles are still controversially discussed. OBJECTIVES: This study aimed to generate science-based evidence for understanding the functional loading of the PCL, including the anterolateral and posteromedial bundles, in the healthy knee joint through systematic review and statistical analysis of the literature...
2016: PloS One
John L Semple, G W Kent Moore, Petros Koutrakis, Jack M Wolfson, Paolo Cristofanelli, Paolo Bonasoni
Semple, John L., G.W. Kent Moore, Petros Koutrakis, Jack M. Wolfson, Paolo Cristofanelli, and Paolo Bonasoni. High concentrations of ozone air pollution on Mount Everest: health implications for Sherpa communities and mountaineers. High Alt Med Biol. 17:365-369, 2016.-Introduction: Populations in remote mountain regions are increasingly vulnerable to multiple climate mechanisms that influence levels of air pollution. Few studies have reported on climate-sensitive health outcomes unique to high altitude ecosystems...
December 2016: High Altitude Medicine & Biology
Parco Chan, Abby Li, Bosco Paes, Haben Abraha, Ian Mitchell, Krista L Lanctôt
BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections in infants. Palivizumab, a means of passive prophylaxis, relies on patient adherence to ensure therapeutic effectiveness. The objective of this study is to evaluate the association between adherence and the incidence of RSV-associated outcomes and to identify demographic factors that may impact adherence. METHODS: Infants were recruited into the Canadian registry of palivizumab (CARESS) with parental consent...
December 2015: Pediatric Infectious Disease Journal
Vasily Struchkov, John G Buckley
BACKGROUND: Walking down slopes and/or over uneven terrain is problematic for unilateral trans-tibial amputees. Accordingly, 'ankle' devices have been added to some dynamic-response feet. This study determined whether use of a microprocessor controlled passive-articulating hydraulic ankle-foot device improved the gait biomechanics of ramp descent in comparison to conventional ankle-foot mechanisms. METHODS: Nine active unilateral trans-tibial amputees repeatedly walked down a 5° ramp, using a hydraulic ankle-foot with microprocessor active or inactive or using a comparable foot with rubber ball-joint (elastic) 'ankle' device...
February 2016: Clinical Biomechanics
André Lacroix, Reto W Kressig, Thomas Muehlbauer, Yves J Gschwind, Barbara Pfenninger, Othmar Bruegger, Urs Granacher
BACKGROUND: Losses in lower extremity muscle strength/power, muscle mass and deficits in static and particularly dynamic balance due to aging are associated with impaired functional performance and an increased fall risk. It has been shown that the combination of balance and strength training (BST) mitigates these age-related deficits. However, it is unresolved whether supervised versus unsupervised BST is equally effective in improving muscle power and balance in older adults. OBJECTIVE: This study examined the impact of a 12-week BST program followed by 12 weeks of detraining on measures of balance and muscle power in healthy older adults enrolled in supervised (SUP) or unsupervised (UNSUP) training...
2016: Gerontology
Levi J Hargrove, Aaron J Young, Ann M Simon, Nicholas P Fey, Robert D Lipschutz, Suzanne B Finucane, Elizabeth G Halsne, Kimberly A Ingraham, Todd A Kuiken
IMPORTANCE: Some patients with lower leg amputations may be candidates for motorized prosthetic limbs. Optimal control of such devices requires accurate classification of the patient's ambulation mode (eg, on level ground or ascending stairs) and natural transitions between different ambulation modes. OBJECTIVE: To determine the effect of including electromyographic (EMG) data and historical information from prior gait strides in a real-time control system for a powered prosthetic leg capable of level-ground walking, stair ascent and descent, ramp ascent and descent, and natural transitions between these ambulation modes...
June 9, 2015: JAMA: the Journal of the American Medical Association
Yonatan Munk, Stephen P Yanoviak, M A R Koehl, Robert Dudley
Gliding ants avoid predatory attacks and potentially mortal consequences of dislodgement from rainforest canopy substrates by directing their aerial descent towards nearby tree trunks. The ecologically relevant measure of performance for gliding ants is the ratio of net horizontal to vertical distance traveled over the course of a gliding trajectory, or glide index. To study variation in glide index, we measured three-dimensional trajectories of Cephalotes atratus ants gliding in natural rainforest habitats...
May 2015: Journal of Experimental Biology
Aleksey N Simonov
A functional approach to the multivariate statistical model of a generalized incoherent passive optical ranging and imaging system with a CCD sensor is proposed. This approach implies that a large number of discrete, statistically independent, random data (pixel readouts) can be approximated by a continuous random function. Thus, the joint probability density function (PDF) takes a functional form; the statistical averages of the infinite-variate PDF and the Fisher information become functional integrals that can be treated analytically in the Gaussian approximation...
December 1, 2014: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Pedro A Forero, Paul A Baxley
Passive sonar is an attractive technology for underwater acoustic-source localization that enables the localization system to conceal its presence and does not perturb the maritime environment. Notwithstanding its appeal, passive-sonar-based localization is challenging due to the complexities of underwater acoustic propagation. Different from alternatives based on matched-field processing whose localization performance severely deteriorate when localizing multiple sources and when faced with model mismatch, this work casts the broadband underwater acoustic-source localization problem as a multitask learning (MTL) problem, thereby enabling robust and high-resolution localization...
April 2014: Journal of the Acoustical Society of America
Tomonori Minagawa, Teruyuki Ogawa, Osamu Ishizuka, Osamu Nishizawa
PURPOSE: We developed a new method to evaluate pelvic organ prolapse dynamically in patients in supine and standing positions using transrectal ultrasonography. We visualized the descent and prolapse of pelvic organs in real time using dynamic transrectal ultrasonography. The dynamic transrectal ultrasonography findings were compared with intraoperative findings. MATERIALS AND METHODS: A prospective analysis was performed including 31 women with symptomatic pelvic organ prolapse...
February 2015: Journal of Urology
Nathaniel T Pickle, Jason M Wilken, Jennifer M Aldridge, Richard R Neptune, Anne K Silverman
Individuals with a unilateral transtibial amputation have a greater risk of falling compared to able-bodied individuals, and falling on stairs can lead to serious injuries. Individuals with transtibial amputations have lost ankle plantarflexor muscle function, which is critical for regulating whole-body angular momentum to maintain dynamic balance. Recently, powered prostheses have been designed to provide active ankle power generation with the goal of restoring biological ankle function. However, the effects of using a powered prosthesis on the regulation of whole-body angular momentum are unknown...
October 17, 2014: Journal of Biomechanics
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