Sagittal Subtalar and Talocrural Joint Assessment With Weight-Bearing Fluoroscopy During Barefoot Ambulation

Background: Identifying talar position during ambulation has proved difficult as the talus lacks palpable landmarks for skin marker placement and more invasive methodologies such as bone pins are not practical for most clinical subjects. A fluoroscopic motion system was used to track the talus and calcaneus, allowing kinematic analysis of the talocrural and subtalar joints. Methods: Thirteen male subjects (mean age 22.9 ± 3.0 years) previously screened for normal gait were tested. A fluoroscopy unit was used to collect images at 120 fps during stance. Sagittal motion of the talocrural and subtalar joints were analyzed. Results: The intersubject mean and standard deviation values for all 58 trials of 13 subjects are reported. Maximum talocrural joint plantarflexion of 11.2 degrees (4.3 degrees of standard deviation) occurred at 11% stance and maximum dorsiflexion of −6.9 degrees (5.6 degrees of standard deviation) occurred at 85%. Maximum subtalar joint plantarflexion of 4.8 degrees (1.0 degrees of standard deviation) occurred at 96% stance and maximum dorsiflexion of −3.6 degrees (2.3 degrees of standard deviation) occurred at 30%. Talocrural and subtalar range of motion values during stance were 18.1 and 8.4 degrees, respectively. Conclusion: Existing fluoroscopic technology was capable of defining sagittal plane talocrural and subtalar motion during gait. These kinematic results compare favorably with more invasive techniques. This type of assessment could support more routine analysis of in vivo bony motion during gait. Clinical Relevance: Fluoroscopic technology offers improved sagittal plane motion evaluation during weight-bearing with potential application in patients with end-stage ankle arthritis, postoperative ankle replacements and fusions, and orthotics and braces

Sagittal Subtalar and Talocrural Joint Assessment During Ambulation With Controlled Ankle Movement (CAM) Boots

Background: The purpose of the current study was to determine sagittal plane talocrural and subtalar kinematic differences between barefoot and controlled ankle movement (CAM) boot walking. This study used fluoroscopic images to determine talar motion relative to tibia and calcaneal motion relative to talus. Methods: Fourteen male subjects (mean age 24.1 ± 3.5 years) screened for normal gait were tested. A fluoroscopy unit was used to collect images at 200 Hz during stance. Sagittal motion of the talocrural and subtalar joints were analyzed barefoot and within short and tall CAM boots. Results: Barefoot talocrural mean maximum plantar and dorsiflexion were 9.2 ± 5.4 degrees and −7.5 ± 7.4 degrees, respectively; short CAM boot mean maximum plantar and dorsiflexion were 3.2 ± 4.0 degrees and −4.8 ± 10.2 degrees, respectively; and tall CAM boot mean maximum plantar and dorsiflexion were −0.2 ± 3.5 degrees and −2.4 ± 5.1 degrees, respectively. Talocrural mean range of motion (ROM) decreased from barefoot (16.7 ± 5.1 degrees) to short CAM boot (8.0 ± 4.9 degrees) to tall CAM boot (2.2 ± 2.5 degrees). Subtalar mean maximum plantarflexion angles were 5.3 ± 5.6 degrees for barefoot walking, 4.1 ± 5.9 degrees for short CAM boot walking, and 3.0 ± 4.7 degrees for tall CAM boot walking. Mean minimum subtalar plantarflexion angles were 0.7 ± 3.2 degrees for barefoot walking, 0.7 ± 2.9 degrees for short CAM boot walking, and 0.1 ± 4.8 degrees for tall CAM boot walking. Subtalar mean ROM decreased from barefoot (4.6 ± 3.9 degrees) to short CAM boot (3.4 ± 3.8 degrees) to tall CAM boot (2.9 ± 2.6 degrees). Conclusion: Tall and short CAM boot intervention was shown to limit both talocrural and subtalar motion in the sagittal plane during ambulation. The greatest reductions were seen with the tall CAM boot, which limited talocrural motion by 86.8% and subtalar motion by 37.0% compared to barefoot. Short CAM boot intervention reduced talocrural motion by 52.1% and subtalar motion by 26.1% compared to barefoot. Clinical Relevance: Both short and tall CAM boots reduced talocrural and subtalar motion during gait. The short CAM boot was more convenient to use, whereas the tall CAM boot more effectively reduced motion. In treatments requiring greater immobilization of the talocrural and subtalar joints, the tall CAM boot should be considered

Effects of four commercially available factor Xa proteins on the fluorogenic anti-factor Xa assay when monitoring unfractionated heparin

Four commercially available factor Xa (FXa) reagents were evaluated in a fluorogenic anti-FXa assay. The four reagents - of which three were of human origin and the fourth was bovine - were compared in terms of the resulting assay dynamic ranges, lag times, coefficient of variation and R 2 values, as well as their sensitivity to unfractionated heparin within the therapeutic range of 0-1.2U/ml. Similar performance of reagents in the fluorogenic anti-FXa assay was observed independent of the source of the reagent or its physical state, which may assist in the standardization of coagulation assays in clinical settings. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Cryogenic Durability of a Carbon Fiber Reinforced Cyanate Ester Composite: Degree-of-Cure Effect

The James Webb Space Telescope (JWST) will be located approximately 1.5 million kilometers from Earth, producing extremely cold temperatures on the optical portion of the observatory. Specifically, the Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) will operate at approximately -240 C. Construction of the structural components of the OTE and ISIM require bonding dissimilar materials together, e.g. Invar-36 (an iron-nickel alloy) to a carbon fiber reinforced cyanate ester composite (CFRCE) with an epoxy adhesive. While these materials enable the cryogenic stability required for optical performance, their joint strength at these extreme conditions presents a unique design challenge. Therefore, the current study presents a detailed investigation into the optimization of cryogenic composite durability. It is demonstrated that by controlling the degree-of-cure of a laminate, one can achieve an enhanced resistance to microcracking and an improved residual strength following cryogenic cycling to -253 C

Situationsklassifikation und Bewegungsprognose in Verkehrssituationen mit mehreren Fahrzeugen

Käfer E. Situationsklassifikation und Bewegungsprognose in Verkehrssituationen mit mehreren Fahrzeugen. Bielefeld: Universitätsbibliothek Bielefeld; 2013.Fahrerassistenzsysteme sind in der heutigen Zeit einer der erfolgversprechendsten Beiträge zu mehr Sicherheit auf unseren Straßen. Die intelligenten Helferlein unterstützen den Fahrer aktiv in kritischen Situationen oder erhöhen den Komfort während der Fahrt. Sie sind ein Meilenstein auf dem Weg zu der Vision vom unfallfreien Fahren. Mit Sensoren wie Stereokamera und Radarsystemen ausgestattete Fahrzeuge sind in der Lage die Umwelt wahrzunehmen und die Bewegungsrichtung der Verkehrsteilnehmer zu schätzen. Mit Methoden der künstlichen Intelligenz erfolgt eine Bewertung der Verkehrssituation auf Kritikalität. Je nach Kritikalität einer Situation werden unterschiedliche Warn- und Unterstützungskonzepte eingesetzt. Das Ziel ist es, den Fahrer auf eine gefährliche Situation hinzuweisen oder bei einem unvermeidbaren Unfall die Aufprallenergie durch einen Bremseingriff zu reduzieren. Gegen Auffahrunfälle im Längsverkehr gibt es bereits ein aktives Sicherheitssystem, den Bremsassistenten. Diese Arbeit hat das Ziel die Situationsanalyse für heutige Sicherheitssysteme auf Kreuzungssituationen zu erweitern. Dazu werden Algorithmen zur frühzeitigen Erkennung von gefährlichen Kreuzungssituationen vorgeschlagen. Der Fokus des ersten Ansatzes liegt auf der Analyse aller Fahreraktionen zweier kreuzender Fahrzeuge. Die kollisionsfreien Kombinationen von Bewegungsoptionen spannen einen zusammengesetzten Aktionsraum zweier Fahrer auf. Aus diesem Aktionsraum wird eine Wahrscheinlichkeit für die Gefahr einer Situation abgeleitet. In einem Versuchsträger integriert zeigt unsere Gefahrenschätzung im Realverkehr eine hohe Performanz und Zuverlässigkeit. Die Vermeidung der Falschwarnungen solcher Systeme ist eine der Herausforderungen, die es hier zu minimieren gilt. Gemessene Bewegungsmuster eines Fahrzeugs werden im zweiten Ansatz als Wissensbasis für eine Prognose eingesetzt. Bei mehreren Fahrzeugen lässt sich in den meisten Kreuzungssituationen eine Interaktion der Fahrer beobachten. Ein Modell für das Interaktionsverhalten ermöglicht eine realistischere Bewegungsprognose für mehrere Fahrzeuge. Im letzten Ansatz werden Bewegungsmuster zweier kreuzender Fahrzeuge in Betracht gezogen. Ein Interaktionsverhalten zwischen den Fahrern liegt dort bereits in den Daten vor. Eine anschauliche und kompakte Repräsentation der interaktiven Bewegungsmuster zweier Fahrzeuge fungiert als Wissensbasis für eine Situationserkennung und Bewegungsprognose

Brief scales to assess physical activity and sedentary equipment in the home

<p>Abstract</p> <p>Background</p> <p>Sedentary behaviors such as TV viewing are associated with childhood obesity, while physical activity promotes healthy weight. The role of the home environment in shaping these behaviors among youth is poorly understood. The study purpose was to examine the reliability of brief parental proxy-report and adolescent self-report measures of electronic equipment and physical activity equipment in the home and to assess the construct validity of these scales by examining their relationship to physical activity, sedentary behavior, and weight status of children and adolescents.</p> <p>Methods</p> <p>Participants were adolescents (n = 189; mean age = 14.6), parents of adolescents (n = 171; mean age = 45.0), and parents of younger children (n = 116; parents mean age = 39.6; children's mean age = 8.3) who completed two surveys approximately one month apart. Measures included a 21-item electronic equipment scale (to assess sedentary behavior facilitators in the home, in the child or adolescent's bedroom, and portable electronics) and a 14-item home physical activity equipment scale. Home environment factors were examined as correlates of children's and adolescents' physical activity, sedentary behavior, and weight status after adjusting for child age, sex, race/ethnicity, household income, and number of children in the home.</p> <p>Results</p> <p>Most scales had acceptable test-retest reliability (intraclass correlations were .54 - .92). Parent and adolescent reports were correlated. Electronic equipment in adolescents' bedrooms was positively related to sedentary behavior. Activity equipment in the home was inversely associated with television time in adolescents and children, and positively correlated with adolescents' physical activity. Children's BMI z-score was positively associated with having a television in their bedroom.</p> <p>Conclusions</p> <p>The measures of home electronic equipment and activity equipment were similarly reliable when reported by parents and by adolescents. Home environment attributes were related to multiple obesity-related behaviors and to child weight status, supporting the construct validity of these scales.</p

Effects of ventilation strategy on distribution of lung inflammatory cell activity

Introduction: Leukocyte infiltration is central to the development of acute lung injury, but it is not known how mechanical ventilation strategy alters the distribution or activation of inflammatory cells. We explored how protective (vs. injurious) ventilation alters the magnitude and distribution of lung leukocyte activation following systemic endotoxin administration. Methods: Anesthetized sheep received intravenous endotoxin (10 ng/kg/min) followed by 2 h of either injurious or protective mechanical ventilation (n = 6 per group). We used positron emission tomography to obtain images of regional perfusion and shunting with infused 13N[nitrogen]-saline and images of neutrophilic inflammation with 18F-fluorodeoxyglucose (18F-FDG). The Sokoloff model was used to quantify 18F-FDG uptake (Ki), as well as its components: the phosphorylation rate (k3, a surrogate of hexokinase activity) and the distribution volume of 18F-FDG (Fe) as a fraction of lung volume (Ki = Fe × k3). Regional gas fractions (fgas) were assessed by examining transmission scans. Results: Before endotoxin administration, protective (vs. injurious) ventilation was associated with a higher ratio of partial pressure of oxygen in arterial blood to fraction of inspired oxygen (PaO2/FiO2) (351 ± 117 vs. 255 ± 74 mmHg; P < 0.01) and higher whole-lung fgas (0.71 ± 0.12 vs. 0.48 ± 0.08; P = 0.004), as well as, in dependent regions, lower shunt fractions. Following 2 h of endotoxemia, PaO2/FiO2 ratios decreased in both groups, but more so with injurious ventilation, which also increased the shunt fraction in dependent lung. Protective ventilation resulted in less nonaerated lung (20-fold; P < 0.01) and more normally aerated lung (14-fold; P < 0.01). Ki was lower during protective (vs. injurious) ventilation, especially in dependent lung regions (0.0075 ± 0.0043/min vs. 0.0157 ± 0.0072/min; P < 0.01). 18F-FDG phosphorylation rate (k3) was twofold higher with injurious ventilation and accounted for most of the between-group difference in Ki. Dependent regions of the protective ventilation group exhibited lower k3 values per neutrophil than those in the injurious ventilation group (P = 0.01). In contrast, Fe was not affected by ventilation strategy (P = 0.52). Lung neutrophil counts were not different between groups, even when regional inflation was accounted for. Conclusions: During systemic endotoxemia, protective ventilation may reduce the magnitude and heterogeneity of pulmonary inflammatory cell metabolic activity in early lung injury and may improve gas exchange through its effects predominantly in dependent lung regions. Such effects are likely related to a reduction in the metabolic activity, but not in the number, of lung-infiltrating neutrophils

In Vitro Dissolution Tests of Plutonium and Americium Containing Contamination Originating From ZPPR Fuel Plates

Assessing the extent of internal dose is of concern whenever workers are exposed to airborne radionuclides or other contaminants. Internal dose determinations depend upon a reasonable estimate of the expected biological half-life of the contaminants in the respiratory tract. One issue with refractory elements is determining the dissolution rate of the element. Actinides such as plutonium (Pu) and Americium (Am) tend to be very refractory and can have biological half-lives of tens of years. In the event of an exposure, the dissolution rates of the radionuclides of interest needs to be assessed in order to assign the proper internal dose estimates. During the November 2011 incident at the Idaho National Laboratory (INL) involving a ZPPR fuel plate, air filters in a constant air monitor (CAM) and a giraffe filter apparatus captured airborne particulate matter. These filters were used in dissolution rate experiments to determine the apparent dissolution half-life of Pu and Am in simulated biological fluids. This report describes these experiments and the results. The dissolution rates were found to follow a three term exponential decay equation. Differences were noted depending upon the nature of the biological fluid simulant. Overall, greater than 95% of the Pu and 93% of the Am were in a very slow dissolving component with dissolution half-lives of over 10 years

Early twentieth-century Vogue, George Wolfe Plank and the "Freaks of Mayfair"

Vogue was one of the most influential fashion magazines of the twentieth century. In the 1920s its British edition, launched in 1916, became a focus for various forms of queer visual and cultural expression. The origins of the related ‘amusing style’, which delighted in camp display, can be traced to the romantic and artistic collaboration between the American artist George Wolfe Plank and the British writer E. F. Benson during World War One. The illustrations that Plank produced for Benson’s book of satirical sketches of life in London’s high society, The Freaks of Mayfair (1916), shed light on the camp images that Plank designed for the covers of both the American and British editions of the magazine. Therefore, Plank can be understood to have played a key role in the development of queer visual culture during the early twentieth century