Life Sciences Commons^™

External Work Is Deficient In Both Limbs Of Patients With Unilateral Pad, Shane R. Wurdeman, Sara A. Myers, Jason Johanning, Iraklis Pipinos, Nikolaos Stergiou

Journal Articles

External work was utilized to measure differences between the unaffected and the affected limb in patients with unilateral peripheral arterial disease compared to healthy controls. Patients with unilateral peripheral arterial disease have shown deficits in peak joint powers during walking in the unaffected and affected legs. However, no research has detailed the amount of work that is being performed by each leg compared to healthy controls even though such an analysis would provide valuable information on the energy output from the affected and the unaffected legs. Two hypotheses were tested: a) the unaffected and affected leg would perform less work …

Sensitivity Of The Wolf’S And Rosenstein’S Algorithms To Evaluate Local Dynamic Stability From Small Gait Data Sets: Response To Commentaries By Bruijn Et Al., Fabien Cignetti, Leslie M. Decker, Nikolaos Stergiou

Journal Articles

Assessing gait stability using the Largest Lyapunov Exponent (λ₁) has become popular, especially because it may be a key measure in evaluating gait abnormalities in patient populations. However, clinical settings usually involve having small gait data sets and accurate determination of λ₁ estimates from such sets is difficult. In an effort to address this issue, Cignetti et al.2 recently identified that λ₁ estimates using the algorithm of Wolf et al.9 (W-algorithm) were more sensitive than those using the algorithm of Rosenstein et al.7 (R-algorithm) in order to capture age-related …

Peripheral Arterial Disease Affects The Frequency Response Of Ground Reaction Forces During Walking, Denise Mcgrath, Timothy N. Judkins, Iraklis Pipinos, Jason Johanning

Journal Articles

Background—Walking is problematic for patients with Peripheral Arterial Disease. The purpose of this study was to investigate the frequency domain of the ground reaction forces during walking to further elucidate the ambulatory impairment of these patients.

Methods—Nineteen bilateral peripheral arterial disease patients and nineteen controls were included in this study. Subjects were matched for age and gait speed. Participants walked over a force plate sampling at 600Hz. PAD patients were tested before (pain-free condition) after the onset of claudication symptoms (pain). We calculated median frequency, frequency bandwidth, and frequency containing 99.5% of the signal for the vertical and …

A Tale Of Two Zoos, Irus Braverman

Journal Articles

This short piece tells the story of the Israeli occupation through the relationship between two zoos: the Biblical Zoo in Jerusalem and the Qalqilya Zoo in the West Bank. Despite the insistence by all interviewees that the zoos’ animals exist beyond the contentious politics of this place, this essay demonstrates that the two zoos are deeply entangled in hegemonic relations. The Israelis have the animals, the professional means, and the education. And as they give, take, and educate their Palestinian counterparts, they also create and enforce the proper conservation standards, thereby controlling the meaning of care for zoo animals, both …

Zooveillance: Foucault Goes To The Zoo, Irus Braverman

Journal Articles

The last three decades have witnessed a dramatic shift in the governance of North American zoo animals. During this period, captive animal administration has transformed from a materially, geographically, and technologically limited enterprise - focused on the control of individual zoo animals within specific institutions - into an ambitious collective project that encompasses all accredited North American zoos and that governs more than a million zoo animals. Tapping into a sophisticated voluntary and collaborative self-monitored administration, zoos have been able to rely upon genetics and demography to achieve the ultimate goal of captive animal conservation. This essay frames this story …

Peripheral Arterial Disease Affects The Frequency Response Of Ground Reaction Forces During Walking, Denise Mcgrath, Timothy N. Judkins, Iraklis Pipinos, Jason M. Johanning, Sara A. Myers

Journal Articles

Background

Walking is problematic for patients with peripheral arterial disease. The purpose of this study was to investigate the frequency domain of the ground reaction forces during walking to further elucidate the ambulatory impairment of these patients.

Methods

Nineteen bilateral peripheral arterial disease patients and nineteen controls were included in this study. Subjects were matched for age and gait speed. Participants walked over a force plate sampling at 600 Hz. PAD patients were tested before (pain-free condition) after the onset of claudication symptoms (pain). We calculated median frequency, frequency bandwidth, and frequency containing 99.5% of the signal for the vertical …

Hamstring-Dominant Strategy Of The Bone–Patellar Tendon–Bone Graft Anterior Cruciate Ligament–Reconstructed Leg Versus Quadriceps-Dominant Strategy Of The Contralateral Intact Leg During High-Intensity Exercise In Male Athletes, Kostas Patras, Franceska Zampeli, Stavros Ristanis, Elias Tsepis, Giorgos Ziogas, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

Purpose

The purpose of this study was to investigate the effect of anterior cruciate ligament (ACL) reconstruction on the quadriceps-dominant strategy as a parameter associated with the neuromuscular control of the knee joint.

Methods

In this study 14 competitive soccer players who had undergone ACL reconstruction with bone–patellar tendon–bone autograft and 14 healthy competitive soccer players performed two 10-minute treadmill runs, 1 at moderate intensity and 1 at high intensity. Electromyographic recordings were acquired by use of a telemetric system at the third, fifth, seventh, and tenth minute of the runs from the vastus lateralis and the biceps femoris bilaterally. …

Postural Control Strategy During Standing Is Altered In Patients With Multiple Sclerosis, Jessie M. Huisinga, Jenna M. Yentes, Mary Filipi, Nikolaos Stergiou

Journal Articles

Disturbances in balance are one of the first reported symptoms of Multiple Sclerosis (MS), yet limited research has been performed to classify the postural control deficits in this population. This study investigated the variability present in the sway patterns during quiet standing in patients with MS (PwMS) and healthy controls. Subjects were assessed (eyes open, closed) standing on a force platform. Variability of the sway patterns was quantified using a measure of amount of variability (root mean square; RMS) and two measures of temporal structure of variability (Lyapunov Exponent – LyE; Approximate Entropy – ApEn). RMS results revealed significantly higher …

Taking Balance Measurement Out Of The Laboratory And Into The Home: Discriminatory Capability Of Novel Centre Of Pressure Measurement In Fallers And Non-Fallers, Denise Mcgrath, Emer P. Doheny, Lorcan Walsh, David Mckeown, Clodagh Cunningham, Lisa Crosby, Rose Anne Kenny, Nikolaos Stergiou, Brian Caulfield, Barry R. Greene

Journal Articles

We investigated three methods for estimating centre of pressure excursions, as measured using a portable pressure sensor matrix, in order to deploy similar technology into the homes of older adults for longitudinal monitoring of postural control and falls risk. We explored the utility of these three methods as markers of falls risk in a cohort of 120 community dwelling older adults with and without a history of falls (65 fallers, 55 non-fallers). A number of standard quantitative balance parameters were derived using each centre of pressure estimation method. Rank sum tests were used to test for significant differences between fallers …

Path Integration: Effect Of Curved Path Complexity And Sensory System On Blindfolded Walking, Panagiotis Koutakis, Mukul Mukherjee, Srikant Vallabhajosula, David J. Blanke, Nikolaos Stergiou

Journal Articles

Path integration refers to the ability to integrate continuous information of the direction and distance traveled by the system relative to the origin. Previous studies have investigated path integration through blindfolded walking along simple paths such as straight line and triangles. However, limited knowledge exists regarding the role of path complexity in path integration. Moreover, little is known about how information from different sensory input systems (like vision and proprioception) contributes to accurate path integration. The purpose of the current study was to investigate how sensory information and curved path complexity affect path integration. Forty blindfolded participants had to accurately …

Use Of Motor Abundance In Young And Older Adults During Dual-Task Treadmill Walking, Leslie M. Decker, Fabien Cignetti, Jane F. Potter, Stephanie A. Studenski, Nikolaos Stergiou

Journal Articles

Motor abundance allows individuals to perform any task reliably while being variable in movement's particulars. The study investigated age-related differences in this feature when young adults (YA) and older adults (OA) performed challenging tasks, namely treadmill walking alone and while performing a cognitive task. A goal function for treadmill walking was first defined, i.e., maintain constant speed at each step, which led to a goal equivalent manifold (GEM) containing all combinations of step time and step length that equally satisfied the function. Given the GEM, amounts of goal-equivalent and non-goal-equivalent variability were afterwards determined and used to define an index …

Patients With Peripheral Arterial Disease Exhibit Reduced Joint Powers Compared To Velocity-Matched Controls, Shane R. Wurdeman, Panagiotis Koutakis, Sara A. Myers, Jason Johanning, Iraklis Pipinos, Nikolaos Stergiou

Journal Articles

Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance ( …

Patients With Peripheral Arterial Disease Exhibit Reduced Joint Powers Compared To Velocity-Matched Controls, Shane Wurdeman, Panagiotis Koutakis, Sara Myers, Jason Johanning, Iraklis Pipinos, Nicholas Stergiou

Journal Articles

Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance ( …

Persons With Multiple Sclerosis Show Altered Joint Kinetics During Walking After Participating In Elliptical Exercise, Jessie M. Huisinga, Kendra K. Schmid, Mary Filipi, Nikolaos Stergiou

Journal Articles

Patients with multiple sclerosis (MS) experience abnormal gait patterns and reduced physical activity. The purpose of this study was to determine if an elliptical exercise intervention for patients with MS would change joint kinetics during gait toward healthy control values. Gait analysis was performed on patients with MS (n = 24) before and after completion of 15 sessions of supervised exercise. Joint torques and powers were calculated, while also using walking velocity as a covariate, to determine the effects of elliptical exercise on lower extremity joint kinetics during gait. Results show that elliptical exercise significantly altered joint torques at the …

Relative Roughness: An Index For Testing The Suitability Of The Monofractal Model, Vivien Marmelat, Kjerstin Torre, Didier Delignières

Journal Articles

Fractal analyses have become very popular and have been applied on a wide variety of empirical time series. The application of these methods supposes that the monofractal framework can offer a suitable model for the analyzed series. However, this model takes into account a quite specific kind of fluctuations, and we consider that fractal analyses have been often applied to series that were completely outside of its relevance. The problem is that fractal methods can be applied to all types of series, and they always give a result, that one can then erroneously interpret in the context of the monofractal …

Pharmacological Treatment Of Intermittent Claudication Does Not Have A Significant Effect On Gait Impairments During Claudication Pain, Jenna M. Yentes, Jessie M. Huisinga, Sara A. Myers, Iraklis Pipinos, Jason Johanning, Nikolaos Stergiou

Journal Articles

Peripheral arterial disease (PAD) is a manifestation of atherosclerosis resulting in intermittent claudication (IC) or leg pain during physical activity. Two drugs (cilostazol and pentoxifylline) are approved for treatment of IC. Our previous work has reported no significant differences in gait biomechanics before and after drug interventions when PAD patients walked without pain. However, it is possible that the drugs are more efficacious during gait with pain. Our aim was to use advanced biomechanical analysis to evaluate the effectiveness of these drugs while walking with pain. Initial and absolute claudication distances, joint kinematics, torques, powers, and gait velocity during the …

Sensitivity Of The Wolf’S And Rostein’S Algorithms To Evaluate Local Dynamic Stability From Small Gait Data Sets, Fabien Cignetti, Leslie M. Decker, Nikolaos Stergiou

Journal Articles

The Wolf’s (W-algorithm) and Rosenstein’s (R-algorithm) algorithms have been used to quantify local dynamic stability (largest Lyapunov exponent, λ ₁) in gait, with prevalence of the latter one that is considered more suitable for small data sets. However, such a claim has never been investigated. To address it, the λ ₁ of the Lorenz attractor was estimated using small data sets and varied delays and embedding dimensions. Overall, the λ ₁ estimates from the R-algorithm got closer to the theoretical exponent than those from the W-algorithm. The W-algorithm also overestimated λ _{1 …}

Gait Variability Measures Reveal Differences Between Multiple Sclerosis Patients And Healthy Controls, Jeffrey P. Kaipust, Jessie M. Huisinga, Mary Filipi, Nikolaos Stergiou

Journal Articles

The purpose of this study was to determine the differences in gait variability between patients with multiple sclerosis (MS) and healthy controls during walking at a self-selected pace. Methods: Kinematics were collected during three minutes of treadmill walking for 10 patients with MS and 10 healthy controls. The Coefficient of Variation (CoV), the Approximate Entropy (ApEn) and the Detrended Fluctuation Analysis (DFA) were used to investigate the fluctuations present in stride length and step width from continuous strides. Results: ApEn revealed that patients with MS had significantly lower values than healthy controls for stride length (p < .001) and step width (p < .001). Conclusions: ApEn results revealed that the natural fluctuations present during gait in the stride length and step width time series are more regular and repeatable in patients with MS. These changes implied that patients with MS may exhibit reduced capacity to adapt and respond to perturbations during gait.

Wearing A Safety Harness During Treadmill Walking Influences Lower Extremity Kinematics Mainly Through Changes In Ankle Regularity And Local Stability, Leslie M. Decker, Fabien Cignetti, Nikolaos Stergiou

Journal Articles

Background: Wearing a harness during treadmill walking ensures the subject’s safety and is common practice in biomedical engineering research. However, the extent to which such practice influences gait is unknown. This study investigated harness-related changes in gait patterns, as evaluated from lower extremity kinematics during treadmill walking.

Findings: Healthy subjects (n = 10) walked on a treadmill at their preferred speed for 3 minutes with and without wearing a harness (LiteGait®, Mobility Research, Inc.). In the former condition, no weight support was provided to the subjects. Lower extremity kinematics was assessed in the sagittal plane from the mean (meanRoM), standard …

Frontal Joint Dynamics When Initiating Stair Ascent From A Walk Versus A Stand, Srikant Vallabhajosula, Jenna M. Yentes, Nikolaos Stergiou

Journal Articles

Ascending stairs is a challenging activity of daily living for many populations. Frontal plane joint dynamics are critical to understand the mechanisms involved in stair ascension as they contribute to both propulsion and medio-lateral stability. However, previous research is limited to understanding these dynamics while initiating stair ascent from a stand. We investigated if initiating stair ascent from a walk with a comfortable self-selected speed could affect the frontal plane lower-extremity joint moments and powers as compared to initiating stair ascent from a stand and if this difference would exist at consecutive ipsilateral steps on the stairs. Kinematics data using …

Do Lower-Extremity Joint Dynamics Change When Stair Negotiation Is Initiated With A Self-Selected Comfortable Gait Speed?, Srikant Vallabhajosula, Jenna M. Yentes, Mira Momcilovic, Daniel Blanke, Nikolaos Stergiou

Journal Articles

Previous research on the biomechanics of stair negotiation has ignored the effect of the approaching speed. We examined if initiating stair ascent with a comfortable self-selected speed can affect the lower-extremity joint moments and powers as compared to initiating stair ascent directly in front of the stairs. Healthy young adults ascended a custom-built staircase instrumented with force platforms. Kinematics and kinetics data were collected simultaneously for two conditions: starting from farther away and starting in front of the stairs and analyzed at the first and second ipsilateral steps. Results showed that for the first step, participants produced greater peak knee …

A Numerical Study On Hydraulic Characteristics In The Ice Harbor-Type Fishway, Seojun Kim, Kwonkyu Yu, Byungman Yoon, Yoonsung Lim

Journal Articles

Recently various types of fishways have been developed and constructed in order to preserve diversity of fish species and restore the riverine ecological system. Some of the fishways in Korea, however, seem to be designed and installed without careful study on their functions and swimming characteristics of target fishes. The present study aims to elucidate proper hydraulic characteristics of the Ice Harbor-type fishway. In the present study, we analyzed the hydraulic characteristics depending on changes in the spans of walls in the Ice Harbor-type fishways, by using Flow-3D, a three dimensional numerical simulation program. Two physical experiments were performed to …

Hightower.2012.A Bayesian Spawning Habitat Suitability Model For American Shad In Southeastern United States Rivers, Joseph E. Hightower, J E. Harris, J K. Raabe, Prescott Brownell, C A. Drew

Journal Articles

Habitat suitability index models for American shad Alosa sapidissima were developed by Stier and Crance in 1985. These models, which were based on a combination of published information and expert opinion, are often used to make decisions about hydropower dam operations and fish passage. The purpose of this study was to develop updated habitat suitability index models for spawning American shad in the southeastern United States, building on the many field and laboratory studies completed since 1985. We surveyed biologists who had knowledge about American shad spawning grounds, assembled a panel of experts to discuss important habitat variables, and used …

Supervised Resistance Training Results In Changes In Postural Control In Patients With Multiple Sclerosis, Jessie M. Huisinga, Mary Filipi, Nikolaos Stergiou

Journal Articles

Postural disturbances are one of the first reported symptoms in patients with Multiple Sclerosis (MS). The purpose of this study was to investigate the effect of supervised resistance training on postural control in MS patients. Postural control was assessed using amount of sway variability [Root Mean Square (RMS)] and temporal structure of sway variability [Lyapunov Exponent (LyE)] from 15 MS patients. Posture was evaluated before and after completion of three months of resistance training. There were significant differences between MS patients pretraining and healthy controls for both LyE (p = .000) and RMS (p = .002), but no differences between …

Variability Of Gait Is Dependent On Direction Of Progression: Implications For Active Control, Shane R. Wurdeman, Neil B. Huben

Journal Articles

Typical healthy walking displays greater variability in the mediolateral direction compared to the anteroposterior direction. This greater variability is thought to represent increased uncertainty in movement. As a result, it has been postulated that the mediolateral direction of gait requires more active control by the central nervous system while the anteroposterior direction is controlled through passive actions. However, this theory has only been tested on gait where progression occurs in the anteroposterior direction. Therefore, the purpose of this study was to investigate how the amount of variability is affected if progression occurs in the mediolateral direction using a lateral stepping …

An Unstable Shoe With A Rocker Bottom Redistributes External Work, Shane R. Wurdeman, Jenna M. Yentes, Neil B. Huben, Nikolaos Stergiou

Journal Articles

The purpose of this study was to examine the external work performed by individuals wearing a rocker bottom shoe compared to a standard shoe. It was hypothesized that individuals wearing a rocker bottom shoe would have changes in the amount of work over the course of contact with the ground. External work on the body’s centre of mass (BCOM) was calculated for individuals in both conditions. Comparisons for external work were done for positive and negative work for the entire stance phase as well as the initial double support, single support and terminal double support periods. The results revealed that …

Estimates Of Critical Power And Anaerobic Work Capacity From A Single, All-Out Test Of Less Than 3-Min, H C. Bergstrom, T J. Housh, Jorge M. Zuniga, C L. Camic, D A. Traylor, R W. Lewis, R J. Schmidt, G O. Johnson

Journal Articles

The purpose of this study was to determine if Critical Power (CP) and Anaerobic Work Capacity (AWC) could be estimated from a single, all-out test of less than 3-min. Twenty-eight subjects (mean ± SD: age 23.3 ± 3.3 years, body mass 71.6 ± 16 kg) performed an incremental cycle ergometer test to exhaustion to determine peak oxygen consumption rate and heart rate peak. The 3-min all-out test was used to determine the criterion and six estimated values of CP and AWC. The criterion critical power (CP180) and anaerobic work capacity (AWC180) values were determined from the 3-min all-out test and …

Training Dual-Task Walking In Community-Dwelling Adults Within 1 Year Of Stroke: A Protocol For A Single-Blind Randomized Controlled Trial, Prudence Plummer-D'Amato, Anastasia Kyvelidou, Dagmar Sternad, Bijan Najafi, Raymond M. Villalobos, David Zurakowski

Journal Articles

No abstract provided.

Reliability Of Semiautomated Computational Methods For Estimating Tibiofemoral Contact Stress In The Multicenter Osteoarthritis Study, Donald D. Anderson, Neil A. Segal, Andrew M. Kern, Michael C. Nevitt, James C. Torner, John A. Lynch

Journal Articles

Recent findings suggest that contact stress is a potent predictor of subsequent symptomatic osteoarthritis development in the knee. However, much larger numbers of knees (likely on the order of hundreds, if not thousands) need to be reliably analyzed to achieve the statistical power necessary to clarify this relationship. This study assessed the reliability of new semiautomated computational methods for estimating contact stress in knees from large population-based cohorts. Ten knees of subjects from the Multicenter Osteoarthritis Study were included. Bone surfaces were manually segmented from sequential 1.0 Tesla magnetic resonance imaging slices by three individuals on two nonconsecutive days. Four …

Glioblastoma Derived Exosomes Induce Apoptosis In Cytotoxic T Cells Through A Fas Ligand Mediated Mechanism , Keith Z. Sabin, Richard A. Rovin, Johnathan Lawrence, Robert J. Belton Jr, Robert J. Winn

Journal Articles

INTRODUCTION: Glioblastoma multiforme deploy s a number of weapons to thwart the immune system. Within the tumor microenvironment, cytotoxic T cells fall victim to Fas ligand (FasL) induced apoptosis. In prostate and colorectal cancer, exosomes can mediate this FasL induced T cell apoptosis. Exosomes are tiny, membrane bound vesicles that are released from a cell. They contain functional mRNA and protein and have cell surface molecules representative of their parent cell. It is not known if GBM derived exosomes can also mediate FasL triggered apoptosis. In this study, the role of tumor derived exosomes as the delivery vehicle for FasL …