150 research outputs found

    SPEXOR passive spinal exoskeleton decreases metabolic cost during symmetric repetitive lifting

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    PURPOSE: Besides mechanical loading of the back, physiological strain is an important risk factor for low-back pain. Recently a passive exoskeleton (SPEXOR) has been developed to reduce loading on the low back. We aimed to assess the effect of this device on metabolic cost of repetitive lifting. To explain potential effects, we assessed kinematics, mechanical joint work, and back muscle activity. METHODS: We recruited ten male employees, working in the luggage handling department of an airline company and having ample experience with lifting tasks at work. Metabolic cost, kinematics, mechanical joint work and muscle activity were measured during a 5-min repetitive lifting task. Participants had to lift and lower a box of 10 kg from ankle height with and without the exoskeleton. RESULTS: Metabolic cost was significantly reduced by 18% when wearing the exoskeleton. Kinematics did not change significantly, while muscle activity decreased by up to 16%. The exoskeleton took over 18-25% of joint work at the hip and L5S1 joints. However, due to large variation in individual responses, we did not find a significant reduction of joint work around the individual joints. CONCLUSION: Wearing the SPEXOR exoskeleton decreased metabolic cost and might, therefore, reduce fatigue development and contribute to prevention of low-back pain during repetitive lifting tasks. Reduced metabolic cost can be explained by the exoskeleton substituting part of muscle work at the hip and L5S1 joints and consequently decreasing required back muscle activity

    Phosphofructo-2-kinase/Fructose-2,6-bisphosphatase Modulates Oscillations of Pancreatic Islet Metabolism

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    Pulses of insulin from pancreatic beta-cells help maintain blood glucose in a narrow range, although the source of these pulses is unclear. It has been proposed that a positive feedback circuit exists within the glycolytic pathway, the autocatalytic activation of phosphofructokinase-1 (PFK1), which endows pancreatic beta-cells with the ability to generate oscillations in metabolism. Flux through PFK1 is controlled by the bifunctional enzyme PFK2/FBPase2 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase) in two ways: via (1) production/degradation of fructose-2,6-bisphosphate (Fru2,6-BP), a potent allosteric activator of PFK1, as well as (2) direct activation of glucokinase due to a protein-protein interaction. In this study, we used a combination of live-cell imaging and mathematical modeling to examine the effects of inducibly-expressed PFK2/FBPase2 mutants on glucose-induced Ca2+ pulsatility in mouse islets. Irrespective of the ability to bind glucokinase, mutants of PFK2/FBPase2 that increased the kinase:phosphatase ratio reduced the period and amplitude of Ca2+ oscillations. Mutants which reduced the kinase:phosphatase ratio had the opposite effect. These results indicate that the main effect of the bifunctional enzyme on islet pulsatility is due to Fru2,6-BP alteration of the threshold for autocatalytic activation of PFK1 by Fru1,6-BP. Using computational models based on PFK1-generated islet oscillations, we then illustrated how moderate elevation of Fru-2,6-BP can increase the frequency of glycolytic oscillations while reducing their amplitude, with sufficiently high activation resulting in termination of slow oscillations. The concordance we observed between PFK2/FBPase2-induced modulation of islet oscillations and the models of PFK1-driven oscillations furthermore suggests that metabolic oscillations, like those found in yeast and skeletal muscle, are shaped early in glycolysis

    Regulation der Beta-Zellen der Langerhans’schen Inseln des Pankreas

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    TRUEDOP – A NEW QUALITY STEP FOR OFFICIAL ORTHOPHOTOS

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    The National Mapping Agencies (NMA) of the German federal states derive nationwide digital orthophotos with a ground resolution of 10 to 20 cm by aerial surveys at regular cycles of two or three years. Standard surveys use large format cameras, the direct georeferencing informations and normal overlap ratios of 70% forward and 30% sideward overlap. These basic geodatasets are in use in a variety of applications. Most commonly authoritive agencies use these orthophotos as a fundamental dataset in their GIS-systems. Interactive work for deriving the orthopohotos is necessary for updating the terrain model and for defining seamlines for objects above the reference plane. With respect to the developments in dense image matching using the semi global matching algorithms it is possible to derive surface models with pixel resolution and full color informations of the aerial photos. Using these high resolutioned height informations for the orthophoto procedure some software solutions are able to derive the quality of true orthophotos without remaining occluded areas. The rectification additionally uses always a height model from the same survey so that there will be no interactive steps in the working process left. TrueDOP visualises the correct position of all objects without the fault effect of the central perspective. This is a basic condition for using the dataset for effective rasterbased classification applications, in special for the use in change detection. The Working Committee of the Surveying Authorities of the States of the Federal Republic Germany (AdV) evaluates the replacement of the classical ATKIS-DOP by the TrueDOP. In this connection the TrueDOP is understood as a qualitative upgrading of the existing AdV-product ATKIS-DOP. The resulting advantages and disadvantages in reference to the technical and economical aspects are considered and compared

    Ophthalmologisches Monitoring der diabetischen Neuropathie am Mausmodell

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    NEED FOR RELIABLE SENSOR CALIBRATION FROM THE PERSPECTIVE OF A NATIONAL MAPPING AGENCY

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    The sensor calibration is one of the basic elements for getting effective and efficient production workflows out of airborne photogrammetry. Digital images and their orientations (interior and exterior) are the key to get the resulting products into the workflow of a national mapping agency (NMCA). Not only the geometric calibration is required meanwhile the radiometric calibration as well is used, for example in raster-based classification processes. In the paper the requirements are shown and examples are presented. At least open aspects and the outstanding debts are given

    TRUEDOP – A NEW QUALITY STEP FOR OFFICIAL ORTHOPHOTOS

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    The National Mapping Agencies (NMA) of the German federal states derive nationwide digital orthophotos with a ground resolution of 10 to 20 cm by aerial surveys at regular cycles of two or three years. Standard surveys use large format cameras, the direct georeferencing informations and normal overlap ratios of 70% forward and 30% sideward overlap. These basic geodatasets are in use in a variety of applications. Most commonly authoritive agencies use these orthophotos as a fundamental dataset in their GIS-systems. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt; Interactive work for deriving the orthopohotos is necessary for updating the terrain model and for defining seamlines for objects above the reference plane. With respect to the developments in dense image matching using the semi global matching algorithms it is possible to derive surface models with pixel resolution and full color informations of the aerial photos. Using these high resolutioned height informations for the orthophoto procedure some software solutions are able to derive the quality of true orthophotos without remaining occluded areas. The rectification additionally uses always a height model from the same survey so that there will be no interactive steps in the working process left. TrueDOP visualises the correct position of all objects without the fault effect of the central perspective. This is a basic condition for using the dataset for effective rasterbased classification applications, in special for the use in change detection. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt; The Working Committee of the Surveying Authorities of the States of the Federal Republic Germany (AdV) evaluates the replacement of the classical ATKIS-DOP by the TrueDOP. In this connection the TrueDOP is understood as a qualitative upgrading of the existing AdV-product ATKIS-DOP. The resulting advantages and disadvantages in reference to the technical and economical aspects are considered and compared.</jats:p

    Konfokal mikroskopisch sichtbarer kornealer Nervenplexus als Biomarker für systemische Erkrankungen

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