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Find video protocols related to scientific articles indexed in Pubmed.
A dynamical systems analysis of assisted and unassisted anterior and posterior hand-held load carriage.
Ergonomics
PUBLISHED: 11-15-2014
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Load carriage is recognised as a primary occupational factor leading to slip and fall injuries, and therefore assessing balance maintenance during such tasks is critical in assessing injury risk. Ten males completed 55 strides under five carriage conditions: (1) unassisted anterior, (2) unassisted posterior, (3) assisted anterior, (4) assisted posterior and (5) unloaded gait (UG). Kinematic data were recorded from markers affixed to landmarks on the right side of each participant, in order to calculate segment angles for the foot, shank, thigh and pelvis. Continuous relative phase (CRP) variability was calculated for each segment pair and local dynamic stability was calculated for each segment in all three movement planes. In general, irrespective of the assistive device or movement plane, anterior load carriage was most stable (lower CRP variability and maximum finite-time Lyapunov exponents). Moreover, load carriage was less dynamically stable than UG, displaying the importance of objectively investigating safe load carriage practices.
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Impact of chiropractic services at an on-site health center.
J. Occup. Environ. Med.
PUBLISHED: 08-26-2014
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To compare the influence of employer-sponsored, on-site chiropractic care against community-obtained care on health care utilization.
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Efficacy of pheromone trapping of the sweetpotato weevil (Coleoptera: Brentidae): based on dose, septum age, attractive radius, and mass trapping.
Environ. Entomol.
PUBLISHED: 04-07-2014
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Pheromone dose, effective trapping distance, and longevity of the rubber septa loaded with sex pheromone of Cylas formicarius (F.) (Coleoptera: Brentidae) were evaluated for their impact on the efficacy of mass trapping of the insect in sweet potato fields in Guam in 2012-2013. The number of adults caught at different distances (10-100 m) was significantly different. Catches declined with increasing release distance from the trap in both downwind and upwind directions. While the maximum radius of attraction of pheromone-baited trap for C. formicarius in the field was 80 m, the effective distance for recapturing marked adults in the pheromone-baited Unitraps was 60 m. Pheromone lures were able to capture adults of C. formicarius after being stored in the laboratory for up to 98 d. The number of catches per trap per week was highest when lures were 0-14- and 15-28-d-old, and longer storage of septa led to a progressive reduction of catches. Pheromone traps baited with 100-?g lures captured significantly more adults compared with those loaded with 10-?g lures. In addition, effectiveness of pheromone trapping on damage to sweet potato was tested at two locations. Number of trapped adults, damage level at different times after trap installation, and yield production were evaluated. The number of C. formicarius adults collected in traps at both locations fluctuated dramatically among sampling dates and peaked on 13 September 2013, after which time the number of captures noticeably declined. This decrease was correlated to the increasing age and depletion of the pheromone lures. Pheromone traps significantly reduced feeding damage caused by weevils (<1 feeding hole per root in treatment; up to 38 feeding holes per root in the control) at both locations. Being consistent with damage levels, sweet potato yields in fields with traps were higher than those in untreated controls. We conclude that pheromone-baited traps are effective in reducing damage due to C. formicarius.
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Implementation of a pharmacy-based adult vaccine benefit: recommendations for a commercial health plan benefit.
J Manag Care Pharm
PUBLISHED: 02-26-2014
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Although vaccination rates in children exceed 90% in the United States, adults are vaccinated at far lower rates. In order to address this issue, additional community immunizers are needed, and pharmacists are in an ideal position to fill this void.
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A comparison of muscle energy models for simulating human walking in three dimensions.
J Biomech
PUBLISHED: 01-22-2014
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The popular Hill model for muscle activation and contractile dynamics has been extended with several different formulations for predicting the metabolic energy expenditure of human muscle actions. These extended models differ considerably in their approach to computing energy expenditure, particularly in their treatment of active lengthening and eccentric work, but their predictive abilities have never been compared. In this study, we compared the predictions of five different Hill-based muscle energy models in 3D forward dynamics simulations of normal human walking. In a data-tracking simulation that minimized muscle fatigue, the energy models predicted metabolic costs that varied over a three-fold range (2.45-7.15 J/m/kg), with the distinction arising from whether or not eccentric work was subtracted from the net heat rate in the calculation of the muscle metabolic rate. In predictive simulations that optimized neuromuscular control to minimize the metabolic cost, all five models predicted similar speeds, step lengths, and stance phase durations. However, some of the models predicted a hip circumduction strategy to minimize metabolic cost, while others did not, and the accuracy of the predicted knee and ankle angles and ground reaction forces also depended on the energy model used. The results highlights the need to clarify how eccentric work should be treated when calculating muscle energy expenditure, the difficulty in predicting realistic metabolic costs in simulated walking even with a detailed 3D musculoskeletal model, the potential for using such models to predict energetically-optimal gait modifications, and the room for improvement in existing muscle energy models and locomotion simulation frameworks.
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Selective lateral muscle activation in moderate medial knee osteoarthritis subjects does not unload medial knee condyle.
J Biomech
PUBLISHED: 01-20-2014
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There is some debate in the literature regarding the role of quadriceps-hamstrings co-contraction in the onset and progression of knee osteoarthritis. Does co-contraction during walking increase knee contact loads, thereby causing knee osteoarthritis, or might it be a compensatory mechanism to unload the medial tibial condyle? We used a detailed musculoskeletal model of the lower limb to test the hypothesis that selective activation of lateral hamstrings and quadriceps, in conjunction with inhibited medial gastrocnemius, can actually reduce the joint contact force on the medial compartment of the knee, independent of changes in kinematics or external forces. "Baseline" joint loads were computed for eight subjects with moderate medial knee osteoarthritis (OA) during level walking, using static optimization to resolve the system of muscle forces for each subject's scaled model. Holding all external loads and kinematics constant, each subject's model was then perturbed to represent non-optimal "OA-type" activation based on mean differences detected between electromyograms (EMG) of control and osteoarthritis subjects. Knee joint contact forces were greater for the "OA-type" than the "Baseline" distribution of muscle forces, particularly during early stance. The early-stance increase in medial contact load due to the "OA-type" perturbation could implicate this selective activation strategy as a cause of knee osteoarthritis. However, the largest increase in the contact load was found at the lateral condyle, and the "OA-type" lateral activation strategy did not increase the overall (greater of the first or second) medial peak contact load. While "OA-type" selective activation of lateral muscles does not appear to reduce the medial knee contact load, it could allow subjects to increase knee joint stiffness without any further increase to the peak medial contact load.
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How well do we communicate?: a comparison of intraoperative diagnoses listed in pathology reports and operative notes.
Am. J. Clin. Pathol.
PUBLISHED: 10-15-2013
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To compare surgeons interpretations of intraoperative diagnoses with those rendered by the pathologist.
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Pheochromocytoma - review and biochemical workup.
S D Med
PUBLISHED: 08-21-2013
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A commonly received question in the clinical laboratory is as follows: what is the best test for pheochromocytoma? A widely variable presentation and potentially catastrophic consequence make this a feared neoplasm despite its infrequent encounter. Because various biochemical testing modalities are available, test selection is often confusing. This selection process can be made easier through a better understanding of catecholamine producing neoplasms. The aim of this article is to provide a review of catecholamine producing neoplasms and give recommendations on appropriate test selection.
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Asymmetric Synthesis of Vabicaserin via Oxidative Multicomponent Annulation and Asymmetric Hydrogenation of a 3,4-Substituted Quinolinium Salt.
Org. Lett.
PUBLISHED: 06-10-2013
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An efficient, asymmetric synthesis of the 5-HT2C agonist vabicaserin in four chemical steps and 54% overall yield from commercially available benzodiazepine was achieved. The synthesis was highlighted by a novel oxidative, multicomponent reaction to affect the quinolinium ring assembly in one step followed by an unprecedented asymmetric hydrogenation of a 3,4-substituted quinolinium salt.
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Is there an association between elevated or low serum levels of phosphorus, parathyroid hormone, and calcium and mortality in patients with end stage renal disease? A meta-analysis.
BMC Nephrol
PUBLISHED: 03-25-2013
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Biochemical markers of altered mineral metabolism have been associated with increased mortality in end stage renal disease patients. Several studies have demonstrated non-linear (U-shaped or J-shaped) associations between these minerals and mortality, though many researchers have assumed linear relationships in their statistical modeling. This analysis synthesizes the non-linear relationships across studies.
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Amputee locomotion: Lower extremity loading using running-specific prostheses.
Gait Posture
PUBLISHED: 02-14-2013
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Carbon fiber running-specific prostheses (RSPs) have allowed individuals with lower extremity amputation (ILEA) to actively participate in sporting activities including competitive sports. In spite of this positive trait, the RSPs have not been thoroughly evaluated regarding potential injury risks due to abnormal loading during running. Vertical impact peak (VIP) and average loading rate (VALR) of the vertical ground reaction force (vGRF) have been associated with running injuries in able-bodied runners but not for ILEA. The purpose of this study was to investigate vGRF loading in ILEA runners using RSPs across a range of running speeds. Eight ILEA with unilateral transtibial amputations and eight control subjects performed overground running at three speeds (2.5, 3.0, and 3.5m/s). From vGRF, we determined VIP and VALR, which was defined as the change in force divided by the time of the interval between 20 and 80% of the VIP. We observed that VIP and VALR increased in both ILEA and control limbs with an increase in running speed. Further, the VIP and VALR in ILEA intact limbs were significantly greater than ILEA prosthetic limbs and control subject limbs for this range of running speeds. These results suggest that (1) loading variables increase with running speed not only in able-bodied runners, but also in ILEA using RSPs, and (2) the intact limb in ILEA may be exposed to a greater risk of running related injury than the prosthetic limb or able-bodied limbs.
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Amputee locomotion: spring-like leg behavior and stiffness regulation using running-specific prostheses.
J Biomech
PUBLISHED: 02-06-2013
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Carbon fiber running-specific prostheses (RSPs) have allowed individuals with lower extremity amputation (ILEA) to participate in running. It has been established that as running speed increases, leg stiffness (Kleg) remains constant while vertical stiffness (Kvert) increases in able-bodied runners. The Kvert further depends on a combination of the torsional stiffnesses of the joints (joint stiffness; Kjoint) and the touchdown joint angles. Thus, an increased understanding of spring-like leg function and stiffness regulation in ILEA runners using RSPs is expected to aid in prosthetic design and rehabilitation strategies. The aim of this study was to investigate stiffness regulation to various overground running speeds in ILEA wearing RSPs. Eight ILEA performed overground running at a range of running speeds. Kleg, Kvert and Kjoint were calculated from kinetic and kinematic data in both the intact and prosthetic limbs. Kleg and Kvert in both the limbs remained constant when running speed increased, while intact limbs in ILEA running with RSPs have a higher Kleg and Kvert than residual limbs. There were no significant differences in Kankle, Kknee and touchdown knee angle between the legs at all running speeds. Hip joints in both the legs did not demonstrate spring-like function; however, distinct impact peaks were observed only in the intact leg hip extension moment at the early stance phase, indicating that differences in Kvert between limbs in ILEA are due to attenuating shock with the hip joint. Therefore, these results suggest that ILEA using RSPs has a different stiffness regulation between the intact and prosthetic limbs during running.
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Predicting sagittal plane biomechanics that minimize the axial knee joint contact force during walking.
J Biomech Eng
PUBLISHED: 02-01-2013
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Both development and progression of knee osteoarthritis have been associated with the loading of the knee joint during walking. We are, therefore, interested in developing strategies for changing walking biomechanics to offload the knee joint without resorting to surgery. In this study, simulations of human walking were performed using a 2D bipedal forward dynamics model. A simulation generated by minimizing the metabolic cost of transport (CoT) resembled data measured from normal human walking. Three simulations targeted at minimizing the peak axial knee joint contact force instead of the CoT reduced the peak force by 12-25% and increased the CoT by 11-14%. The strategies used by the simulations were (1) reduction in gastrocnemius muscle force, (2) avoidance of knee flexion during stance, and (3) reduced stride length. Reduced gastrocnemius force resulted from a combination of changes in activation and changes in the gastrocnemius contractile component kinematics. The simulations that reduced the peak contact force avoided flexing the knee during stance when knee motion was unrestricted and adopted a shorter stride length when the simulated knee motion was penalized if it deviated from the measured human knee motion. A higher metabolic cost in an offloading gait would be detrimental for covering a long distance without fatigue but beneficial for exercise and weight loss. The predicted changes in the peak axial knee joint contact force from the simulations were consistent with estimates of the joint contact force in a human subject who emulated the predicted kinematics. The results demonstrate the potential of using muscle-actuated forward dynamics simulations to predict novel joint offloading interventions.
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The Spectral Properties of (-)-Epigallocatechin 3-O-Gallate (EGCG) Fluorescence in Different Solvents: Dependence on Solvent Polarity.
PLoS ONE
PUBLISHED: 01-01-2013
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(-)-Epigallocatechin 3-O-gallate (EGCG) a molecule found in green tea and known for a plethora of bioactive properties is an inhibitor of heat shock protein 90 (HSP90), a protein of interest as a target for cancer and neuroprotection. Determination of the spectral properties of EGCG fluorescence in environments similar to those of binding sites found in proteins provides an important tool to directly study protein-EGCG interactions. The goal of this study is to examine the spectral properties of EGCG fluorescence in an aqueous buffer (AB) at pH=7.0, acetonitrile (AN) (a polar aprotic solvent), dimethylsulfoxide (DMSO) (a polar aprotic solvent), and ethanol (EtOH) (a polar protic solvent). We demonstrate that EGCG is a highly fluorescent molecule when excited at approximately 275 nm with emission maxima between 350 and 400 nm depending on solvent. Another smaller excitation peak was found when EGCG is excited at approximately 235 nm with maximum emission between 340 and 400 nm. We found that the fluorescence intensity (FI) of EGCG in AB at pH=7.0 is significantly quenched, and that it is about 85 times higher in an aprotic solvent DMSO. The Stokes shifts of EGCG fluorescence were determined by solvent polarity. In addition, while the emission maxima of EGCG fluorescence in AB, DMSO, and EtOH follow the Lippert-Mataga equation, its fluorescence in AN points to non-specific solvent effects on EGCG fluorescence. We conclude that significant solvent-dependent changes in both fluorescence intensity and fluorescence emission shifts can be effectively used to distinguish EGCG in aqueous solutions from EGCG in environments of different polarity, and, thus, can be used to study specific EGCG binding to protein binding sites where the environment is often different from aqueous in terms of polarity.
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Small cell carcinoma of the renal pelvis and ureter: clinicopathologic and immunohistochemical features.
Arch. Pathol. Lab. Med.
PUBLISHED: 12-02-2011
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Small cell carcinoma (SCC) of the renal pelvis and/or ureter is very rare, with only case reports published in the literature.
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Evaluation of the minimum energy hypothesis and other potential optimality criteria for human running.
Proc. Biol. Sci.
PUBLISHED: 11-09-2011
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A popular hypothesis for human running is that gait mechanics and muscular activity are optimized in order to minimize the cost of transport (CoT). Humans running at any particular speed appear to naturally select a stride length that maintains a low CoT when compared with other possible stride lengths. However, it is unknown if the nervous system prioritizes the CoT itself for minimization, or if some other quantity is minimized and a low CoT is a consequential effect. To address this question, we generated predictive computer simulations of running using an anatomically inspired musculoskeletal model and compared the results with data collected from human runners. Three simulations were generated by minimizing the CoT, the total muscle activation or the total muscle stress, respectively. While all the simulations qualitatively resembled real human running, minimizing activation predicted the most realistic joint angles and timing of muscular activity. While minimizing the CoT naturally predicted the lowest CoT, minimizing activation predicted a more realistic CoT in comparison with the experimental mean. The results suggest a potential control strategy centred on muscle activation for economical running.
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Lower extremity joint moments during carrying tasks in children.
J Appl Biomech
PUBLISHED: 10-04-2011
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Farm youth often carry loads that are proportionally large and/or heavy, and field measurements have determined that these tasks are equivalent to industrial jobs with high injury risks. The purpose of this study was to determine the effects of age, load amount, and load symmetry on lower extremity joint moments during carrying tasks. Three age groups (8-10 years, 12-14 years, adults), three load amounts (0%, 10%, 20% BW), and three load symmetry levels (unilateral large bucket, unilateral small bucket, bilateral small buckets) were tested. Inverse dynamics was used to determine maximum ankle, knee, and hip joint moments. Ankle dorsiflexion, ankle inversion, ankle eversion, knee adduction, and hip extension moments were significantly higher in 8-10 and 12-14 year olds. Ankle plantar flexion, ankle inversion, knee extension, and hip extension moments were significantly increased at 10% and 20% BW loads. Knee and hip adduction moments were significantly increased at 10% and 20% BW loads when carrying a unilateral large bucket. Of particular concern are increased ankle inversion and eversion moments for children, along with increased knee and hip adduction moments for heavy, asymmetrical carrying tasks. Carrying loads bilaterally instead of unilaterally avoided increases in knee and hip adduction moments with increased load amount.
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Long-term safety and benefit of a new intraoral device for single-sided deafness.
Otol. Neurotol.
PUBLISHED: 07-30-2011
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To determine the long-term safety and benefit of a new intraoral bone conduction device (SoundBite Hearing System by Sonitus Medical) for single-sided deafness (SSD).
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Cost-effectiveness of natalizumab versus fingolimod for the treatment of relapsing multiple sclerosis.
J Med Econ
PUBLISHED: 07-22-2011
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With the addition of new agents for the treatment of multiple sclerosis (MS) (e.g., fingolimod), there is a need to evaluate the relative value of newer therapies in terms of cost and effectiveness, given healthcare resource constraints in the United States.
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Managing the risks of on-site health centers.
AAOHN J
PUBLISHED: 05-26-2011
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This review sought to assess compliance concerns, determine risk management strategies, and identify opportunities for future research to contribute to employers understanding of the laws and regulations that apply to on-site care. A comprehensive review of databases, professional organizations websites, and journals resulted in 22 publications reporting on the consequences of noncompliance among on-site health centers accepted for inclusion. None of those studies reported a study design or quantifiable outcome data. Two noncompliance themes were repeated among the publications. First, direct penalties included fines, civil actions, loss of licensure, and, potentially, criminal charges. Second, noncompliance also resulted in indirect costs such as employee mistrust and lowered standards of care, which jeopardize on-site health centers ability to demonstrate a return on investment. Further research with rigorous methodology is needed to inform employer decisions about on-site health services and associated risk management.
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Aortoesophageal fistula secondary to aortic dissection: case report and review.
S D Med
PUBLISHED: 05-13-2011
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Aortoesophageal fistula (AEF) formation nearly always results in catastrophic consequences. As a result of its development being extremely rare, many may never consider it in their differential. Although prognosis is extremely grim, early diagnosis and intervention is considered the optimal means to enhance ones prognosis. We present a case of AEF formation secondary to a Stanford B aortic dissection, along with a review of literature and terminology involved in describing such pathology.
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Systematic review of efficacy of dose-dense versus non-dose-dense chemotherapy in breast cancer, non-Hodgkin lymphoma, and non-small cell lung cancer.
Crit. Rev. Oncol. Hematol.
PUBLISHED: 04-12-2011
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Randomized controlled trials (RCTs) have suggested a potential advantage of dose-dense chemotherapy in improving disease-free and overall survival in patients with certain malignancies. This systematic review summarizes the literature on the efficacy of dose-dense chemotherapy across various cancers (breast cancer, non-Hodgkin lymphoma [NHL], and non-small cell lung cancer) and chemotherapy regimens. Among the 17 trials identified, few reported statistically significant differences between dose-dense and standard chemotherapy, and most were small with limited statistical power. Statistically significant differences in overall survival favoring dose-dense schedules were apparent among large RCTs in potentially curative settings such as early-stage breast cancer and NHL. Clinical and treatment heterogeneity demonstrated the flexibility of the dose-dense paradigm but also precluded quantitative meta-analysis of results. Further study of dose-dense schedules based on large RCTs is needed to demonstrate the consistency and generalizability of these findings.
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Limitations to maximum sprinting speed imposed by muscle mechanical properties.
J Biomech
PUBLISHED: 02-16-2011
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It has been suggested that the force-velocity relationship of skeletal muscle plays a critical limiting role in the maximum speed at which humans can sprint. However, this theory has not been tested directly, and it is possible that other muscle mechanical properties play limiting roles as well. In this study, forward dynamics simulations of human sprinting were generated using a 2D musculoskeletal model actuated by Hill muscle models. The initial simulation results compared favorably to kinetic, kinematic, and electromyographic data recorded from sprinting humans. Muscle mechanical properties were then removed in isolation to quantify their effect on maximum sprinting speed. Removal of the force-velocity, excitation-activation, and force-length relationships increased the maximum speed by 15, 8, and 4%, respectively. Removal of the series elastic force-extension relationship decreased the maximum speed by 26%. Each relationship affected both stride length and stride frequency except for the force-length relationship, which mainly affected stride length. Removal of all muscular properties entirely (optimized joint torques) increased speed (+22%) to a greater extent than the removal of any single contractile property. The results indicate that the force-velocity relationship is indeed the most important contractile property of muscle regarding limits to maximum sprinting speed, but that other muscular properties also play important roles. Interactions between the various muscular properties should be considered when explaining limits to maximal human performance.
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Efficacy and safety of an in-the-mouth bone conduction device for single-sided deafness.
Otol. Neurotol.
PUBLISHED: 01-12-2011
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To determine the efficacy, benefit, and safety of a new in-the-mouth bone conduction device (SoundBite Hearing System) for single-sided deafness (SSD).
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Contractile and elastic ankle joint muscular properties in young and older adults.
PLoS ONE
PUBLISHED: 01-11-2011
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The purpose of this study was to investigate age-related differences in contractile and elastic properties of both dorsi- (DF) and plantarflexor (PF) muscles controlling the ankle joint in young and older adults. Experimental data were collected while twelve young and twelve older male and female participants performed maximal effort isometric and isovelocity contractions on a dynamometer. Equations were fit to the data to give torque-angle (T?) and torque-angular velocity (T?) relations. Muscle series-elasticity was measured during ramped dynamometer contractions using ultrasonography to measure aponeurosis extension as a function of torque; second order polynomials were used to characterize the torque-extension (T?L) relation. The results showed no age differences in DF maximal torque and none for female PF; however, older males had smaller maximal PF torques compared to young males. In both muscle groups and genders, older adults had decreased concentric force capabilities. Both DF and PF T?L relations were more nonlinear in the older adults. Older PF, but not DF muscles, were stiffer compared to young. A simple antagonism model suggested age-related differences in T? and T? relations would be magnified if antagonistic torque contributions were included. This assessment of static, dynamic, and elastic joint properties affords a comprehensive view of age-related modifications in muscle function. Although many clinical studies use maximal isometric strength as a marker of functional ability, the results demonstrate that there are also significant age-related modifications in ankle muscle dynamic and elastic properties.
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Safety of an intra-oral hearing device utilizing a split-mouth research design.
J Clin Dent
PUBLISHED: 01-01-2011
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The auditory deficits of Single Sided Deafness (SSD) can be treated effectively with a novel device, SoundBite, that delivers sound by applying imperceptible vibratory signals to the teeth (hereafter referred to as an intra-oral hearing device). The intra-oral hearing device is placed around two maxillary teeth and is similar to a small partial denture or retainer. The goal of this study was to report how this removable hearing device affects the oral structures.
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Acute vesiculopapular rash in the setting of atopic dermatitis.
S D Med
PUBLISHED: 12-01-2010
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Atopic dermatitis is a common entity encountered in clinical practice. A subgroup within the atopic dermatitis cohort may develop viral infection on skin lesions appearing as a vesiculopapular pattern. This process is termed eczema herpeticum and may pose a challenge to the clinician as it can appear similar to orthopoxvirus infections, most notably smallpox and monkeypox. Because these conditions are considered as potential bioterrorism threats, confirmatory testing via histological examination, viral culture, immunohistochemical staining or PCR is recommended. Additionally, antiviral therapy should be promptly initiated as eczema herpeticum can disseminate or become superinfected with bacterial species. Early recognition and good communication with pathology can reduce morbidity and confirm the disease process.
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Variability in kinematic coupling assessed by vector coding and continuous relative phase.
J Biomech
PUBLISHED: 05-12-2010
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Variability in the spatio-temporal coordination of human movement kinematics is often assessed by vector coding and continuous relative phase (CRP). To facilitate appropriate comparisons between the findings of studies that have used different techniques to assess variability, the purposes of this study were: (1) to determine if both vector coding and CRP behave according to dynamical systems theories on variability and state space transitions; and (2) to determine if trends in coordination variability during movement are consistent when using either vector coding or CRP. We present both a theoretical case (the Lorenz Attractor) and two experimental cases (rearfoot-forefoot coupling during overground walking for 22 subjects; the effect of treadmill speed on thigh-leg coupling for five subjects). In the theoretical case, variability quantified by CRP agreed with dynamical systems theory on state space transitions more so than variability quantified by vector coding. In experimental cases, this distinction was less clear, although CRP appeared to be a more conservative metric for variability. The magnitudes (all p<0.001) and timings (all p<0.04) of peaks in variability during the stance phase of overground walking depended on whether vector coding or CRP was used for two couplings. Similar distinctions were observed for peaks during the stride cycle of treadmill locomotion (all effect sizes >2.8). However, changes in the average variability during the stride cycle as speed increased were consistent for both methods (all effect sizes <0.2). The results suggest that comparisons between the findings of studies that have quantified variability using CRP and those that have used vector coding should be made with caution.
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Bacteriophage therapy for control of necrotic enteritis of broiler chickens experimentally infected with Clostridium perfringens.
Avian Dis.
PUBLISHED: 04-23-2010
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Several lytic bacteriophages effective at destroying a genetically diverse population of Clostridium perfringens were isolated from the environment, extensively characterized, and used to formulate a multivalent bacteriophage cocktail designated -401." Two in vivo studies were conducted to determine the cocktails efficacy in controlling necrotic enteritis (NE) caused by C. perfringens. The first study investigated the efficacy of INT-401 and a bacteriophage-derived, toxoid-type vaccine in controlling NE in C. perfringens-challenged broiler chickens. The study was designed as a proof-of-concept battery cage study with birds reared until 28 days old. Compared with the mortality observed with the C. perfringens-challenged but untreated chickens, oral administration of INT-401 significantly (P < 0.05) reduced the mortality of the C. perfringens-challenged birds by 92%. Overall, INT-401 was more effective than the toxoid vaccine in controlling active C. perfringens infection. The second study was conducted to investigate the effectiveness of the cocktail when administered via oral gavage, feed, or drinking water. The study was conducted in floor pens, with birds reared to 42 days old. INT-401 administered by all three methods significantly (P < 0.05) reduced mortality. Weight gain and feed conversion ratios were significantly better in the C, perfringens-challenged chickens treated with INT-401 than in the C. perfringens-challenged, phage-untreated control birds. The data indicate that delivering INT-401 to broiler chickens via their drinking water or feed may be an effective means for controlling NE caused by C. perfringens and may improve weight gain and feed conversion ratios in birds with clinical or subclinical NE.
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The effects of age and type of carrying task on lower extremity kinematics.
Ergonomics
PUBLISHED: 03-02-2010
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The purpose of this study was to determine the effects of age, load amount and load symmetry on lower extremity kinematics during carrying tasks. Forty-two participants in four age groups (8-10 years, 12-14 years, 15-17 years and adults) carried loads of 0%, 10% and 20% body weight (BW) in large or small buckets unilaterally and bilaterally. Reflective markers were tracked to determine total joint range of motion and maximum joint angles during the stance phase of walking. Maximum hip extension, hip adduction and hip internal rotation angles were significantly greater for each of the child/adolescent age groups as compared with adults. In addition, maximum hip internal rotation angles significantly increased when carrying a 20% BW load. The observation that the 8-10-year-old age group carried the lightest absolute loads and still displayed the highest maximum hip internal rotation angles suggests a particular necessity in setting carrying guidelines for the youngest children. STATEMENT OF RELEVANCE: Bucket-carrying tasks were analysed as a function of age group, load amount and load symmetry. Hip joint rotations significantly increased when carrying 20% BW loads and in children as compared to adults, which suggests a particular necessity in setting carrying guidelines for the youngest age group (8-10 year olds).
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Its time we listened to our teeth: the SoundBite hearing system.
Am J Orthod Dentofacial Orthop
PUBLISHED: 01-01-2010
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The SoundBite hearing system (Sonitus Medical, San Mateo, Calif) allows people with single-sided deafness to wear an intraoral device and a small microphone in the deaf ear to regain lost hearing. A piezoelectric activator in a small removable unilateral oral appliance conducts sound through the bone via the teeth to the good ear. The goal of this article is to introduce the SoundBite, a new bone-conduction hearing device, to dentists and orthodontists.
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Ground reaction forces and lower extremity kinematics when running with suppressed arm swing.
J Biomech Eng
PUBLISHED: 07-11-2009
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The role of arm swing in running has been minimally described, and the contributions of arm motion to lower extremity joint kinematics and external force generation are unknown. These contributions may have implications in the design of musculoskeletal models for computer simulations of running, since previous models have usually not included articulating arm segments. 3D stance phase lower extremity joint angles and ground reaction forces (GRFs) were determined for seven subjects running normally, and running under two conditions of arm restraint. When arm swing was suppressed, the peak vertical GRF decreased by 10-13% bodyweight, and the peak lateral GRF increased by 4-6% bodyweight. Changes in peak joint angles on the order of 1-5 deg were observed for hip flexion, hip adduction, knee flexion, knee adduction, and ankle abduction. The effect sizes (ES) were small to moderate (ES<0.8) for most of the peak GRF differences, but large (ES>0.8) for most of the peak joint angle differences. These changes suggest that suppression of arm swing induces subtle but statistically significant changes in the kinetic and kinematic patterns of running. However, the salient features of the GRFs and the joint angles were present in all conditions, and arm swing did not introduce any major changes in the timing of these data, as indicated by cross correlations. The decision to include arm swing in a computer model will likely need to be made on a case-by-case basis, depending on the design of the study and the accuracy needed to answer the research question.
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Muscle forces during running predicted by gradient-based and random search static optimisation algorithms.
Comput Methods Biomech Biomed Engin
PUBLISHED: 06-25-2009
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Muscle forces during locomotion are often predicted using static optimisation and SQP. SQP has been criticised for over-estimating force magnitudes and under-estimating co-contraction. These problems may be related to SQPs difficulty in locating the global minimum to complex optimisation problems. Algorithms designed to locate the global minimum may be useful in addressing these problems. Muscle forces for 18 flexors and extensors of the lower extremity were predicted for 10 subjects during the stance phase of running. Static optimisation using SQP and two random search (RS) algorithms (a genetic algorithm and simulated annealing) estimated muscle forces by minimising the sum of cubed muscle stresses. The RS algorithms predicted smaller peak forces (42% smaller on average) and smaller muscle impulses (46% smaller on average) than SQP, and located solutions with smaller cost function scores. Results suggest that RS may be a more effective tool than SQP for minimising the sum of cubed muscle stresses in static optimisation.
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The SNF2-family member Fun30 promotes gene silencing in heterochromatic loci.
PLoS ONE
PUBLISHED: 06-02-2009
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Chromatin regulates many key processes in the nucleus by controlling access to the underlying DNA. SNF2-like factors are ATP-driven enzymes that play key roles in the dynamics of chromatin by remodelling nucleosomes and other nucleoprotein complexes. Even simple eukaryotes such as yeast contain members of several subfamilies of SNF2-like factors. The FUN30/ETL1 subfamily of SNF2 remodellers is conserved from yeasts to humans, but is poorly characterized. We show that the deletion of FUN30 leads to sensitivity to the topoisomerase I poison camptothecin and to severe cell cycle progression defects when the Orc5 subunit is mutated. We demonstrate a role of FUN30 in promoting silencing in the heterochromatin-like mating type locus HMR, telomeres and the rDNA repeats. Chromatin immunoprecipitation experiments demonstrate that Fun30 binds at the boundary element of the silent HMR and within the silent HMR. Mapping of nucleosomes in vivo using micrococcal nuclease demonstrates that deletion of FUN30 leads to changes of the chromatin structure at the boundary element. A point mutation in the ATP-binding site abrogates the silencing function of Fun30 as well as its toxicity upon overexpression, indicating that the ATPase activity is essential for these roles of Fun30. We identify by amino acid sequence analysis a putative CUE motif as a feature of FUN30/ETL1 factors and show that this motif assists Fun30 activity. Our work suggests that Fun30 is directly involved in silencing by regulating the chromatin structure within or around silent loci.
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Computer simulation of the effects of shoe cushioning on internal and external loading during running impacts.
Comput Methods Biomech Biomed Engin
PUBLISHED: 02-20-2009
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Biomechanical aspects of running injuries are often inferred from external loading measurements. However, previous research has suggested that relationships between external loading and potential injury-inducing internal loads can be complex and nonintuitive. Further, the loading response to training interventions can vary widely between subjects. In this study, we use a subject-specific computer simulation approach to estimate internal and external loading of the distal tibia during the impact phase for two runners when running in shoes with different midsole cushioning parameters. The results suggest that: (1) changes in tibial loading induced by footwear are not reflected by changes in ground reaction force (GRF) magnitudes; (2) the GRF loading rate is a better surrogate measure of tibial loading and stress fracture risk than the GRF magnitude; and (3) averaging results across groups may potentially mask differential responses to training interventions between individuals.
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Lateral wedges alter mediolateral load distributions at the knee joint in obese individuals.
J. Orthop. Res.
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Obesity is the primary risk factor for knee osteoarthritis (OA). Greater external knee adduction moments, surrogate measures for medial compartment loading, are present in Obese individuals and may predispose them to knee OA. Laterally wedged insoles decrease the magnitude of the external adduction moment in Obese individuals but it is unknown how they alter the center of pressure on the tibial plateau. A gait analysis was performed on 14 Obese (avg. 29.3 years; BMI range: 30.3-51.6?kg/m(2) ) and 14 lean women (avg. 26.1 years; BMI range: 20.9-24.6?kg/m(2) ) with and without a full-length, wedged insole. Computed joint angles, joint moments, and knee extensor strength values were input into a musculoskeletal model to estimate center of pressure of the contact force on the tibial plateau. Statistical significance was assessed using a two-way ANOVA to compare the main effects of group and insole condition (??=?0.05). The insole resulted in a significant (p?
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Systematic review of employer-sponsored wellness strategies and their economic and health-related outcomes.
Popul Health Manag
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This review determines the characteristics and health-related and economic outcomes of employer-sponsored wellness programs and identifies possible reasons for their success. PubMed, ABI/Inform, and Business Source Premier databases, and Corporate Wellness Magazine were searched. English-language articles published from 2005 to 2011 that reported characteristics of employer-sponsored wellness programs and their impact on health-related and economic outcomes among US employees were accepted. Data were abstracted, synthesized, and interpreted. Twenty references were accepted. Wellness interventions were classified into health assessments, lifestyle management, and behavioral health. Improved economic outcomes were reported (health care costs, return on investment, absenteeism, productivity, workers compensation, utilization) as well as decreased health risks. Programs associated with favorable outcomes had several characteristics in common. First, the corporate culture encouraged wellness to improve employees lives, not only to reduce costs. Second, employees and leadership were strongly motivated to support the wellness programs and to improve their health in general. Third, employees were motivated by a participation-friendly corporate policy and physical environment. Fourth, successful programs adapted to the changing needs of the employees. Fifth, community health organizations provided support, education, and treatment. Sixth, successful wellness programs utilized technology to facilitate health risk assessments and wellness education. Improved health-related and economic outcomes were associated with employer-sponsored wellness programs. Companies with successful programs tended to include wellness as part of their corporate culture and supported employee participation in several key ways.
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SWI/SNF-like chromatin remodeling factor Fun30 supports point centromere function in S. cerevisiae.
PLoS Genet.
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Budding yeast centromeres are sequence-defined point centromeres and are, unlike in many other organisms, not embedded in heterochromatin. Here we show that Fun30, a poorly understood SWI/SNF-like chromatin remodeling factor conserved in humans, promotes point centromere function through the formation of correct chromatin architecture at centromeres. Our determination of the genome-wide binding and nucleosome positioning properties of Fun30 shows that this enzyme is consistently enriched over centromeres and that a majority of CENs show Fun30-dependent changes in flanking nucleosome position and/or CEN core micrococcal nuclease accessibility. Fun30 deletion leads to defects in histone variant Htz1 occupancy genome-wide, including at and around most centromeres. FUN30 genetically interacts with CSE4, coding for the centromere-specific variant of histone H3, and counteracts the detrimental effect of transcription through centromeres on chromosome segregation and suppresses transcriptional noise over centromere CEN3. Previous work has shown a requirement for fission yeast and mammalian homologs of Fun30 in heterochromatin assembly. As centromeres in budding yeast are not embedded in heterochromatin, our findings indicate a direct role of Fun30 in centromere chromatin by promoting correct chromatin architecture.
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Natural experiment demonstrates top-down control of spiders by birds on a landscape level.
PLoS ONE
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The combination of small-scale manipulative experiments and large-scale natural experiments provides a powerful approach for demonstrating the importance of top-down trophic control on the ecosystem scale. The most compelling natural experiments have come from studies examining the landscape-scale loss of apex predators like sea otters, wolves, fish and land crabs. Birds are dominant apex predators in terrestrial systems around the world, yet all studies on their role as predators have come from small-scale experiments; the top-down impact of bird loss on their arthropod prey has yet to be examined at a landscape scale. Here, we use a unique natural experiment, the extirpation of insectivorous birds from nearly all forests on the island of Guam by the invasive brown tree snake, to produce the first assessment of the impacts of bird loss on their prey. We focused on spiders because experimental studies showed a consistent top-down effect of birds on spiders. We conducted spider web surveys in native forest on Guam and three nearby islands with healthy bird populations. Spider web densities on the island of Guam were 40 times greater than densities on islands with birds during the wet season, and 2.3 times greater during the dry season. These results confirm the general trend from manipulative experiments conducted in other systems however, the effect size was much greater in this natural experiment than in most manipulative experiments. In addition, bird loss appears to have removed the seasonality of spider webs and led to larger webs in at least one spider species in the forests of Guam than on nearby islands with birds. We discuss several possible mechanisms for the observed changes. Overall, our results suggest that effect sizes from smaller-scale experimental studies may significantly underestimate the impact of bird loss on spider density as demonstrated by this large-scale natural experiment.
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Value of chiropractic services at an on-site health center.
J. Occup. Environ. Med.
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Chiropractic care offered at an on-site health center could reduce the economic and clinical burden of musculoskeletal conditions.
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Sensitivity of maximum sprinting speed to characteristic parameters of the muscle force-velocity relationship.
J Biomech
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An accumulation of evidence suggests that the force-velocity relationship (FVR) of skeletal muscle plays a major role in limiting maximum human sprinting speed. However, most of the theories on this limiting role have been non-specific as to how the FVR limits speed. The FVR is characterized by three parameters that each have a different effect on its shape, and could thus limit sprinting speed in different ways: the maximum shortening velocity V(max), the shape parameter A(R), and the eccentric plateau C(ecc). In this study, we sought to determine how specifically the FVR limits sprinting speed using forward dynamics simulations of human locomotion to examine the sensitivity of maximum speed to these three FVR parameters. Simulations were generated by optimizing the models muscle excitations to maximize the average horizontal speed. The simulations speed, temporal stride parameters, joint angles, GRF, and muscle activity in general compared well to data from human subjects sprinting at maximum effort. Simulations were then repeated with incremental and isolated adjustments in V(max), A(R), and C(ecc) across a physiological range. The range of speeds (5.22-6.91 m s?¹) was most sensitive when V(max) was varied, but the fastest speed of 7.17 m s?¹ was attained when A(R) was set to its maximum value, which corresponded to all muscles having entirely fast-twitch fibers. This result was explained by the muscle shortening velocities, which tended to be moderate and within the range where A(R) had its greatest effect on the shape of the FVR. Speed was less sensitive to adjustments in C(ecc), with a range of 6.23-6.70 m s?¹. Increases in speed with parameter changes were due to increases in stride length more so than stride frequency. The results suggest that the shape parameter A(R), which primarily determines the amount of muscle force that can be produced at moderate shortening velocities, plays a major role in limiting the maximum sprinting speed. Analysis of muscle force sensitivity indicated support for previous theories on the time to generate support forces in stance (Weyand et al., 2000, Journal of Applied Physiology, 89, 1991-1999) and energy management of the leg in swing (Chapman & Caldwell, 1983, Journal of Biomechanics 16, 79-83) as important factors in limiting maximum speed. However, the ability of the knee flexors to slow the rotational velocity of the leg in preparation for footstrike did not appear to play a major role in limiting speed.
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Biomechanical examination of the plateau phenomenon in ActiGraph vertical activity counts.
Physiol Meas
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This paper determines if the leveling off (plateau/inverted-U phenomenon) of vertical ActiGraph activity counts during running at higher speeds is attributable to the monitors signal filtering and acceleration detection characteristics. Ten endurance-trained male participants (mean (SD) age = 28.2 (4.7) years) walked at 3, 5 and 7 km h(-1), and ran at 8, 10, 12, 14, 16, 18 and 20 km h(-1) on a force treadmill while wearing an ActiGraph GT3X monitor at the waist. Triaxial accelerations of the bodys center of mass (CoM) and frequency content of these accelerations were computed from the force treadmill data. GT3X vertical activity counts demonstrated the expected plateau/inverted-U phenomenon. In contrast, vertical CoM accelerations increased with increasing speed (1.32 ± 0.26 g at 10 km h(-1) and 1.68 ± 0.24 g at 20 km h(-1)). The dominant frequency in the CoM acceleration signals increased with running speed (14.8 ± 3.2 Hz at 10 km h(-1) and 24.8 ± 3.2 Hz at 20 km h(-1)) and lay beyond the ActiGraph band-pass filter (0.25 to 2.5 Hz) limits. In conclusion, CoM acceleration magnitudes during walking and running lie within the ActiGraph monitors dynamic acceleration detecting capability. Acceleration signals of higher frequencies that are eliminated by the ActiGraph band-pass filter may be necessary to distinguish among exercise intensity at higher running speeds.
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Approaches to the management of agents used for the treatment of multiple sclerosis: consensus statements from a panel of U.S. managed care pharmacists and physicians.
J Manag Care Pharm
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Multiple sclerosis (MS) is a chronic, disabling, and costly disease with several treatment options available; however, there is variability in evidence-based clinical guidelines. Therefore, payers are at a disadvantage when making management decisions without the benefit of definitive guidance from treatment guidelines.
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Why Dont Most Runners Get Knee Osteoarthritis? A Case for Per-Unit-Distance Loads.
Med Sci Sports Exerc
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Peak knee joint contact forces ("loads") in running are much higher than they are in walking, where the peak load has been associated with the initiation and progression of knee osteoarthritis. However, runners do not have an especially high risk of osteoarthritis compared to non-runners. This paradox suggests that running somehow blunts the effect of very high peak joint contact forces, perhaps to provide a load per unit distance traveled (PUD) that is relatively low.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.