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Passive descent

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...
December 9, 2016: 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
Pedro A Forero, Paul A Baxley
Using passive sonar for underwater acoustic source localization in a shallow-water environment is challenging due to the complexities of underwater acoustic propagation. Matched-field processing (MFP) exploits both measured and model-predicted acoustic pressures to localize acoustic sources. However, the ambiguity surface obtained through MFP contains artifacts that limit its ability to reveal the location of the acoustic sources. This work introduces a robust scheme for shallow-water source localization that exploits the inherent sparse structure of the localization problem and the use of a model characterizing the acoustic propagation environment...
June 2014: Journal of the Acoustical Society of America
Ozhan M Turan, Sifa Turan, Laura Sanapo, Arne Willruth, Arne Wilruth, Christoph Berg, Ulrich Gembruch, Christopher R Harman, Ahmet A Baschat
OBJECTIVES: The purpose of this study was to establish reference ranges for ductus venosus velocity ratios. METHODS: Singleton pregnancies from 11 to 38 weeks with exactly established gestational ages (GAs) were recruited for the study. Pregnancies with fetal anomalies, growth abnormalities, maternal medical complications, stillbirth, birth weight below the 10th or above the 90th percentile, and neonatal anomalies were excluded. The ductus venosus pulsatility index for veins (PIV) and velocity ratios (S/v, S/D, v/D, S/a, v/a, and D/a, where S indicates ventricular systole [s-wave], v, ventricular end-systolic relaxation [v-descent], D, passive diastolic ventricular filling [D-wave], and a, active ventricular filling during atrial systole [a-wave]) were calculated...
February 2014: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
Joakim Bjerke, Fredrik Öhberg, Kjell G Nilsson, Olav A Foss, Ann K Stensdotter
Reduced peak knee flexion during stair descent (PKSD) is demonstrated in subjects with total knee arthroplasty (TKA), but the underlying factors are not well studied. 3D gait patterns during stair descent, peak passive knee flexion (PPKF), quadriceps strength, pain, proprioception, demographics, and anthropometrics were assessed in 23 unilateral TKA-subjects ~19 months post-operatively, and in 23 controls. PKSD, PPKF and quadriceps strength were reduced in the TKA-side, but also in the contralateral side. A multiple regression analysis identified PPKF as the only predictor (57%) to explain the relationship with PKSD...
April 2014: Journal of Arthroplasty
Deborah Vincent, Marylyn M McEwen, Joseph T Hepworth, Craig S Stump
PURPOSE: The purpose of this article is to describe methods used to recruit and retain high-risk, Spanish-speaking adults of Mexican origin in a randomized clinical trial that adapts Diabetes Prevention Program (DPP) content into a community-based, culturally tailored intervention. METHODS: Multiple passive and active recruitment strategies were analyzed for effectiveness in reaching the recruitment goal. Of 91 potential participants assessed for eligibility, 58 participated in the study, with 38 in the intervention and 20 in the attention control group...
March 2013: Diabetes Educator
Silvana Arrighi, Marina Aralla, Paola Fracassetti, Ali Mobasheri, Fausto Cremonesi
The jelly-like gubernaculum testis (GT) is a hydrated structure consisting of a concentric sheath of dense connective tissue around a loose mesenchymal core, with two cords of skeletal muscle cells asymmetrically placed alongside. Expansion of the GT occurs during the transabdominal phase of testicular descent, linked to cell proliferation together with modifications of the hydric content of the organ. The aim of this study was to detect immunohistochemically the presence of aquaporins (AQPs), integral membrane proteins permitting passive transcellular water movement, in the canine GTs...
July 2013: Acta Histochemica
John G Buckley, Glen Cooper, Constantinos N Maganaris, Neil D Reeves
When descending stairs bodyweight becomes supported on a single limb while the forwards-reaching contralateral limb is lowered in order to make contact with the step below. This is associated with lowering of the centre of mass (CoM), which in order to occur in a controlled manner, requires increased ankle and knee joint torque production relative to that in overground walking. We have previously shown that when descending steps or stairs older people operate at a higher proportion of their maximum eccentric capacity and at, or in excess of the maximum passive reference joint range of motion...
February 2013: Experimental Gerontology
Jennifer M Park, Anthony O Odibo, Anthony L Shanks, Methodius G Tuuli, Kimberly A Roehl, Alison G Cahill
OBJECTIVE: To estimate whether passive descent in the second stage of labor in morbidly obese parturients is associated with reduced active pushing times and improved labor outcomes compared with immediate pushing. METHODS: This was a retrospective cohort study of all consecutive women with a body mass index (BMI) of 40 or greater admitted for term labor that reached the second stage of labor from 2004 to 2008 at a single institution. Detailed information was collected for maternal demographics, labor progress, and neonatal outcomes...
December 2012: Obstetrics and Gynecology
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