229 research outputs found

    Finite Element Analysis in Orthopaedic Biomechanics

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    Vagal modulation of the heart and central hemodynamics during dynamic handgrip exercise and forearm occlusion following forearm exercise training

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    The purpose was to examine the cardiovascular response to an acute bout of handgrip exercise before and after non-dominant arm exercise training. 19 people participated in 16 sessions of exercise training and 16 participants acted as controls (age: 20±1yrs). Blood flow measurements were taken at rest and following 3-min of forearm occlusion (RHBF) using plethysmography. Pneumotachometer, ECG, and blood pressure data were continuously collected during three testing conditions (spontaneous breathing (SB1: 5min), handgrip exercise (0.5hz) at 60%MVC with 50mmHg of pressure on the arm (H60+50mmHg: 5 min), and forearm occlusion (FAO: 3min)). Data were analyzed for respiratory rate, mean R-R interval, standard deviation of normal RR intervals (SDNN), normalized units of low- (0-0.15 hz) frequency power (LFnu), and mean arterial pressure (MAP). There was no main effect of group or arm. There was a main effect of test condition such that respiratory rate (+3.10±5.40breaths/min), LFnu (+19.06±14.73%), and MAP increased (+24.51±21.15mmHg) and mean R-R (-247.11±129.70msec) and SDNN (-45.16±40.65msec) decreased significantly during H60+50mmHg (non-dominant arm; p\u3c0.05). Respiratory rate (-0.10±4.84breaths/min), SDNN (-9.50±57.14msec), and LFnu (-1.64±18.34%) recovered to SB1 levels during. Mean R-R (46.11±106.57msec) and MAP (16.65±15.84mmHg) remained elevated above SB1 (p\u3c0.05). There were positive linear associations between forearm circumference and Mean R-R and MAP during H60+50mmHg; and MAP during FAO. There was a negative linear association with forearm circumference and Mean R-R during FAO. There was no significant main effect or interaction with handgrip exercise training on any of the variables. There was a decrease in vascular resistance during RHBF (0.80±1.08 mmHg/ ml/100ml/min, p\u3c0.05) in the arm that underwent exercise training. In conclusion, we found elevated MAP during FAO, which is indicative of significant EPR activity during exercise. Uniquely, we found linear associations between forearm circumference and the cardiovascular response to H60+50mmHg and FAO suggesting variation in the predominant mechanism of cardiovascular control. We did not see an attenuation of cardiovascular responses to H60+50mmHg and FAO with exercise training. However, we did see a decrease in forearm vascular resistance during the reactive hyperemia condition in the exercise-trained arm

    A comparison of owner perceived and measured body condition, feeding and exercise in sport and pet dogs

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    Dog obesity is a significant problem in the US and elsewhere. The purpose was to evaluate factors contributing to pet obesity in sport and pet dog owners. Owners were recruited over social media to answer a questionnaire regarding demographics, health, body condition, feeding, exercise and dog related expenses. Owners identified as pet or sport dog owners. We asked owners to measure the pelvic circumference and hock to stifle length in their dogs in order to calculate percent fat. Owners reported that their dogs were in “ideal” body condition. However, percent fat calculated from owner measurements was significantly different between groups (Sport: 16 ± 10%fat; Pet: 24 ± 10% fat; p < 0.05) and revealed that over 50% of the dogs were over fat. Owners reported feeding dogs a range of 413 to 1,133 Kilocalories (Kcal) per day that correlated well with dog size (R = 0.58; p < 0.05). The size of the treats fed was smaller in the Sport dogs (treat was pinky nail to thumbnail sized) than in Pet dogs (treat was bigger than thumb to larger than palm). Owners reported walking their dogs on leash every day for 15–45 min per session. Overall, owners did a poor job in identifying correct body condition of their dogs. This is concerning because 50% of the dogs were over fat. Better understanding of correct body condition and feeding for the level of physical activity is still a critical issue in controlling obesity in pet dogs

    Evaluation of range of motion restriction within the hip joint

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    In Total Hip Arthroplasty, determining the impingement free range of motion requirement is a complex task. This is because in the native hip, motion is restricted by both impingement as well as soft tissue restraint. The aim of this study is to determine a range of motion benchmark which can identify motions which are at risk from impingement and those which are constrained due to soft tissue. Two experimental methodologies were used to determine motions which were limited by impingement and those motions which were limited by both impingement and soft tissue restraint. By comparing these two experimental results, motions which were limited by impingement were able to be separated from those motions which were limited by soft tissue restraint. The results show motions in extension as well as flexion combined with adduction are limited by soft tissue restraint. Motions in flexion, flexion combined with abduction and adduction are at risk from osseous impingement. Consequently, these motions represent where the maximum likely damage will occur in femoroacetabular impingement or at most risk of prosthetic impingement in Total Hip Arthroplasty

    Interlaboratory comparison of femur surface reconstruction from CT data compared to reference optical 3D scan

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    Background: The present study contrasts the accuracy of different reconstructed models with distinctive segmentation methods performed by various experts. Seven research groups reconstructed nine 3D models of one human femur based on an acquired CT image using their own computational methods. As a reference model for accuracy assessment, a 3D surface scan of the human femur was created using an optical measuring system. Prior to comparison, the femur was divided into four areas;"neck and greater trochanter", "proximal metaphysis", "diaphysis", and "distal metaphysis". The deviation analysis was carried out in GEOMAGIC studio v. 2013 software. Results: The results revealed that the highest deviation errors occurred in "neck and greater trochanter" area and "proximal metaphysis" area with RMSE of 0.84 and 0.83 mm respectively. Conclusion: In conclusion, this study shows that the average deviation of reconstructed models prepared by experts with various methods, skills and software from the surface 3D scan is lower than 0.79 mm, which is not a significant discrepancy

    Utilization Rate of Outsourcing in Selected Municipalities

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    Cílem bakalářské práce je míra využití outsourcingu v obcích Olomouckého kraje. Zvolený problém jsem vyřešila pomocí metodiky dotazníkového šetření a analýzy získaných dat. Podařilo se získat dostatečné množství vzorků a tím potvrdit, že obce outsourcing využívají. Hlavním přínosem této práce je zjištění, že obce outsourcing využívají ve velké míře. Většina obcí, které odpověděly na dotazník, své činnosti zajišťují externím dodavatelem. Z práce je taky zřejmé, že nejčastější outsourcované činnosti jsou informačních technologie, komunální odpad a právní služby. Obce k zavedení outsourcingu vedou různé důvody, nejčastějším důvodem je přístup k technologiím a lidským zdrojům externím dodavatele. U každého smluvního vztahu mohou vzniknout rizika. Dalším zjištěním je, že nejčastějším rizikem je kvalita poskytované služby a kvalifikace pracovníků dodavatelské firmy.The aim of this thesis is ulitization rate of outsourcing in the selected municipalities of the Olomouc region. The chosen problem I solved using the methodology of the questionnaire survey and the analysis of the obtained data. It was managed to get a sufficient number of samples and thus to confirm that the municipalities use outsourcing. The main contribution of this thesis is findig out that the level of outsourcing use in selected municipalities is very often. The major part of municipalities, which took part in questionnaire survey, make use of external suppliers for their activities. According to questionnaire survey results the most common outsourced activities are information technology, municipal waste and legal services. The municipalities use outsourcing because of a variety of reasons, the most common reason is access to the technology and human resources of external contractor. For each contractual relationship risks can arise. Another finding is that the most common risk is the quality of the provided services and the qualifications of the contractor's staff.153 - Katedra veřejné ekonomikyvýborn

    Sources of Intravascular ATP During Exercise in Humans: Critical Role for Skeletal Muscle Perfusion

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    Exercise hyperemia is regulated by several factors and one factor known to increase with exercise that evokes powerful vasomotor action is extracellular ATP. The origination of ATP detectable in plasma from exercising muscle of humans is, however, a matter of debate and ATP has been suggested to arise from sympathetic nerves, blood sources (e.g. erythrocytes), endothelial cells, and skeletal myocytes, among others. Therefore, we tested the hypothesis that acute augmentation of sympathetic nervous system activity (SNA) results in elevated plasma ATP draining skeletal muscle, and that SNA superimposition during exercise further increases ATP vs exercise alone. We show that increased SNA via −40mmHg lower body negative pressure (LBNP) at rest does not increase plasma ATP (51±8 vs 58±7 nmol/L with LBNP), nor does it increase [ATP] above levels observed during rhythmic handgrip exercise (79±11 exercise alone vs 71±8 nmol/L with LBNP). Secondly, we tested the hypothesis that active perfusion of skeletal muscle is essential to observe increased plasma ATP during exercise. We identify that complete obstruction of blood flow to contracting muscle abolishes exercise-mediated increases in plasma ATP (90±19 to 49±12 nmol/L), and further, that cessation of blood flow prior to exercise completely inhibits the typical rise in ATP (3 vs 61%; obstructed vs intact perfusion). The lack of ATP change during occlusion occurred in the face of continued muscle work and elevated SNA, indicating the rise of intravascular ATP is not resultant from these extravascular sources. Our collective observations indicate that the elevation in extracellular ATP observed in blood during exercise is unlikely to originate from sympathetic nerves or the contacting muscle itself, but rather is dependent on intact skeletal muscle perfusion. We conclude that an intravascular source for ATP is essential and points toward an important role for blood sources (e.g. red blood cells) in augmenting and maintaining elevated plasma ATP during exercise

    Protein Supplementation Throughout 10 Weeks of Progressive Run Training Is Not Beneficial for Time Trial Improvement

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    Introduction: Protein supplementation is proposed to promote recovery and adaptation following endurance exercise. While prior literature demonstrates improved performance when supplementing protein during or following endurance exercise, chronic supplementation research is limited.Methods: Runners (VO2peak = 53.6 ± 8.9 ml/kg/min) were counter-balanced into a placebo group (PLA; n = 8) or protein group (PRO; n = 9) based on sex and VO2peak, and underwent 10 weeks of progressive endurance training. Prior to training, body composition, blood cell differentials, non-invasive mitochondrial capacity using near-infrared spectroscopy, and a 5 km treadmill time trial (TT) were evaluated. Progressive training then commenced (5–10% increase in weekly volume with a recovery week following 3 weeks of training) whereby PRO supplemented with 25 g of whey protein following workouts and prior to sleep (additional 50 g daily). PLA supplemented similarly with a < 1 g sugar pill per day. Following training, participants were reanalyzed for the aforementioned tests.Results: VO2peak and initial 5 km TT were not significantly different between groups. PRO consumed significantly more dietary protein throughout the training period (PRO = 132 g/d or 2.1 g/kg/day; PLA = 84 g/d or 1.2 g/kg/day). Running volume increased significantly over time, but was not significantly different between groups throughout training. Blood measures were unaltered with training or supplementation. Mitochondrial capacity trended toward improving over time (time p = 0.063) with no difference between groups. PLA increased lean mass 0.7 kg (p < 0.05) while PRO experienced infinitesimal change (−0.1 kg, interaction p = 0.049). PLA improved 5 km TT performance 6.4% (1 min 31 s), while PRO improved only 2.7% (40 s) (interaction p = 0.080).Conclusion: This is the first evidence to suggest long-term protein supplementation during progressive run training is not beneficial for runners

    Physiological Concentration of Exogenous Lactate Reduces Antimycin A Triggered Oxidative Stress in Intestinal Epithelial Cell Line IPEC-1 and IPEC-J2 In Vitro

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    Weaning triggers an adaptation of the gut function including luminal lactate generation by lactobacilli, depending on gastrointestinal site. We hypothesized that both lactobacilli and lactate influence porcine intestinal epithelial cells. In vivo experiments showed that concentration of lactate was significantly higher in gastric, duodenal and jejunal chyme of suckling piglets compared to their weaned counterparts. In an in vitro study we investigated the impact of physiological lactate concentration as derived from the in vivo study on the porcine intestinal epithelial cells IPEC-1 and IPEC-J2. We detected direct adherence of lactobacilli on the apical epithelial surface and a modulated F-actin structure. Application of lactobacilli culture supernatant alone or lactate (25 mM) at low pH (pH 4) changed the F-actin structure in a similar manner. Treatment of IPEC cultures with lactate at near neutral pH resulted in a significantly reduced superoxide-generation in Antimycin A-challenged cells. This protective effect was nearly completely reversed by inhibition of cellular lactate uptake via monocarboxylate transporter. Lactate treatment enhanced NADH autofluorescence ratio (F-cytosol/F-nucleus) in non-challenged cells, indicating an increased availability of reduced nucleotides, but did not change the overall ATP content of the cells. Lactobacilli-derived physiological lactate concentration in intestine is relevant for alleviation of redox stress in intestinal epithelial cells.Peer reviewe
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