FPGA-based operational concept and payload data processing for the Flying Laptop satellite

Flying Laptop is the first small satellite developed by the Institute of Space Systems at the Universität Stuttgart. It is a test bed for an on-board computer with a reconfigurable, redundant and self-controlling high computational ability based on the field pro- grammable gate arrays (FPGAs). This Technical Note presents the operational concept and the on-board payload data processing of the satellite. The designed operational concept of Flying Laptop enables the achievement of mission goals such as technical demonstration, scientific Earth observation, and the payload data processing methods. All these capabilities expand its scientific usage and enable new possibilities for real-time applications. Its hierarchical architecture of the operational modes of subsys- tems and modules are developed in a state-machine diagram and tested by means of MathWorks Simulink-/Stateflow Toolbox. Furthermore, the concept of the on-board payload data processing and its implementation and possible applications are described

Survival of gastrointestinal stromal tumor patients in the imatinib era: life raft group observational registry

<p>Abstract</p> <p>Background</p> <p>Gastrointestinal stromal tumors (GIST), one of the most common mesenchymal tumors of the gastrointestinal tract, prior to routine immunohistochemical staining and the introduction of tyrosine kinase inhibitors, were often mistaken for neoplasms of smooth muscle origin such as leiomyomas, leiomyosarcomas or leiomyoblastomas. Since the advent of imatinib, GIST has been further delineated into adult- (KIT or PDGFRα mutations) and pediatric- (typified by wild-type GIST/succinate dehydrogenase deficiencies) types. Using varying gender ratios at age of diagnosis we sought to elucidate prognostic factors for each sub-type and their impact on overall survival.</p> <p>Methods</p> <p>This is a long-term retrospective analysis of a large observational study of an international open cohort of patients from a GIST research and patient advocacy's lifetime registry. Demographic and disease-specific data were voluntarily supplied by its members from May 2000-October 2010; the primary outcome was overall survival. Associations between survival and prognostic factors were evaluated by univariate Cox proportional hazard analyses, with backward selection at <it>P </it>< 0.05 used to identify independent factors.</p> <p>Results</p> <p>Inflections in gender ratios by age at diagnosis in years delineated two distinct groups: above and below age 35 at diagnosis. Closer analysis confirmed the above 35 age group as previously reported for adult-type GIST, typified by mixed primary tumor sites and gender, KIT or PDGFRα mutations, and shorter survival times. The pediatric group (< age 18 at diagnosis) was also as previously reported with predominantly stomach tumors, females, wild-type GIST or SDH mutations, and extended survival. "Young adults" however formed a third group aged 18-35 at diagnosis, and were a clear mix of these two previously reported distinct sub-types.</p> <p>Conclusions</p> <p>Pediatric- and adult-type GIST have been previously characterized in clinical settings and these observations confirm significant prognostic factors for each from a diverse real-world cohort. Additionally, these findings suggest that extra diligence be taken with "young adults" (aged 18-35 at diagnosis) as pediatric-type GIST may present well beyond adolescence, particularly as these distinct sub-types have different causes, and consequently respond differently to treatments.</p

Reliable Prediction of Insulin Resistance by a School-Based Fitness Test in Middle-School Children

Objectives. (1) Determine the predictive value of a school-based test of cardiovascular fitness (CVF) for insulin resistance (IR); (2) compare a “school-based” prediction of IR to a “laboratory-based” prediction, using various measures of fitness and body composition. Methods. Middle school children (n = 82) performed the Progressive Aerobic Cardiovascular Endurance Run (PACER), a school-based CVF test, and underwent evaluation of maximal oxygen consumption treadmill testing (VO2 max), body composition (percent body fat and BMI z score), and IR (derived homeostasis model assessment index [HOMAIR]). Results. PACER showed a strong correlation with VO2 max/kg (rs = 0.83, P < .001) and with HOMAIR (rs = −0.60, P < .001). Multivariate regression analysis revealed that a school-based model (using PACER and BMI z score) predicted IR similar to a laboratory-based model (using VO2 max/kg of lean body mass and percent body fat). Conclusions. The PACER is a valid school-based test of CVF, is predictive of IR, and has a similar relationship to IR when compared to complex laboratory-based testing. Simple school-based measures of childhood fitness (PACER) and fatness (BMI z score) could be used to identify childhood risk for IR and evaluate interventions

Respiratory Depression in Young Prader Willi Syndrome Patients following Clonidine Provocation for Growth Hormone Secretion Testing

Objectives. To determine the sedative and respiratory effects of clonidine when used to evaluate growth hormone (GH) secretion in children with Prader Willi Syndrome (PWS). Methods. The study prospectively evaluated children with PWS who received clonidine (0.15 mg/m2) to assess GH responsiveness. Patients were studied up to four times over three years. Vital signs, oxygen saturation, and sedation level were recorded at baseline and every five minutes following clonidine. Changes between baseline and post-clonidine were evaluated using a repeated measurement analysis. Results. Sixty studies were performed on 17 patients, mean age 30.4 ± 15.0 months. The mean ± SD dose of clonidine was 0.074 ± 0.027 mg (5.3 ± 1.72 mcg/kg). All patients achieved a sedation score of 4 to 5 (drowsy to asleep). Mean declines in respiratory rate (7.5 ± 6.1 breaths/min; P < .001), and oxygen saturation (2.2 ± 2.0%; P < .001) occurred following clonidine. Five patients (29%) experienced oxygen saturations ≤94% on nine occasions. Three oxygen desaturations were accompanied by partial airway obstruction. Conclusions. Clonidine doses to assess GH secretion often exceed doses used for sedation and result in significant respiratory depression in some children with PWS. There was no association between oxygen desaturation and BMI

Development and Testing of Fast and Portable Data-Handling Models in a Synchronous Small Satellite Simulator

On the basis of the small satellite Flying Laptop and its derived platform FLP2, this paper introduces a generic methodology of simulating a satellite on-board computer within an on-board data-handling network. The concept has been developed in order to take on some of the challenges towards a reference testing facility for small satellites. Although the development of a reference testing facility has been the initial motivation, this work does not intend to provide a full concept of such an architecture in any kind, but detail solutions to specific problems down that road. The first challenge is to bind the controller-in-the-loop as close as possible to the satellite system simulator without unnecessary interfaces in between. This means that an appropri- ate simulator needs to provide all required interfaces, as it has to simulate all data-handling devices that are connected to the on-board computer in some way. Unfortunately, the work- ing principle of a state-of-the-art satellite system simulator would causes latencies that rule out a proper simulation of an on-board data-handling, which is why a faster solution must be found here. The second challenge is the derivation of a generic modeling approach for data-handling devices, which supports portability across different simulation projects. A solution here is restricted though by the variety of hardware architectures and protocols especially on trans- port and application layer, which is why this work sticks to the application of SpaceWire and the Remote Memory Access Protocol. Verification of developed models is the third and last challenge met in the scope of this paper. Models of a satellite system simulator are implemented mostly in an object-oriented fashion. Testing object-oriented software does not work straightforward as a matter of principle. It is even more comprehensive, when the respective models are multi-threaded. Therefore, a profound approach of testing these data-handling models must be introduced

Validation of an arterial constitutive model accounting for collagen content and crosslinking

During the progression of pulmonary hypertension (PH), proximal pulmonary arteries (PAs) increase in both thickness and stiffness. Collagen, a component of the extracellular matrix, is mainly responsible for these changes via increased collagen fiber amount (or content) and crosslinking. We sought to differentiate the effects of collagen content and cross-linking on mouse PA mechanical changes using a constitutive model with parameters derived from experiments in which collagen content and cross-linking were decoupled during hypoxic pulmonary hypertension (HPH). We employed an eight-chain orthotropic element model to characterize collagen’s mechanical behavior and an isotropic neo-Hookean form to represent elastin. Our results showed a strong correlation between the material parameter related to collagen content and measured collagen content (R2 = 0.82, P < 0.0001) and a moderate correlation between the material parameter related to collagen crosslinking and measured crosslinking (R2 = 0.24, P = 0.06). There was no significant change in either the material parameter related to elastin or the measured elastin content from histology. The model-predicted pressure at which collagen begins to engage was ∼25 mmHg, which is consistent with experimental observations. We conclude that this model may allow us to predict changes in the arterial extracellular matrix from measured mechanical behavior in PH patients, which may provide insight into prognoses and the effects of therapy

Data Model Canvas für die IT-Systemübergreifende Integration von Datenmodellen zur Unterstützung von Datenanalyse-Anwendungen im Produktlebenszyklus

Der Data Model Canvas (DMC) unterstützt methodisch und informationstechnisch den Aufbau der für ein durchgängiges und interdisziplinäres Engineering benötigten fachlichen Datengrundlage und deren Abbildung in den betreffenden IT-Systemen. Basierend auf konkreten Analyse-Szenarien erfolgt eine Modellierung der erforderlichen Datenvernetzung, die wiederum die explizit benötigten Datenquellen umfasst. Im Mittelpunkt dieses Ansatzes steht die Entwicklung eines fachlichen Verständnisses über die zur Analyse notwendigen roduktdaten. Unterstützt wird der Ansatz durch ein Softwaretool zur Erstellung der benötigten Datenmodelle

Discovery of a novel simian pegivirus in common marmosets (Callithrix jacchus) with lymphocytic enterocolitis

From 2010 to 2015, 73 common marmosets

Exercise-Induced Changes in Pulmonary Artery Stiffness in Pulmonary Hypertension

Background: Pulmonary hypertension causes pulmonary artery (PA) stiffening, which overloads the right ventricle (RV). Since symptoms of pulmonary hypertension (PH) are exacerbated by exercise, exercise-induced PA stiffening is relevant to cardiopulmonary status. Here, we sought to demonstrate the feasibility of using magnetic resonance imaging (MRI) for non-invasive assessment of exercise-induced changes in PA stiffness in patients with PH.Methods: MRI was performed on 7 PH patients and 8 age-matched control subjects at rest and during exercise stress. Main pulmonary artery (MPA) relative area change (RAC) and pulse wave velocity (PWV) were measured from 2D-PC images. Invasive right heart catheterization (RHC) was performed on 5 of the PH patients in conjunction with exercise stress to measure MPA pressures and stiffness index (β).Results: Heart rate and cardiac index (CI) were significantly increased with exercise in both groups. In controls, RAC decreased from 0.27 ± 0.05 at rest to 0.22 ± 0.06 with exercise (P &lt; 0.05); a modest increase in PWV was not significant (P = 0.06). In PH patients, RAC decreased from 0.15 ± 0.02 to 0.11 ± 0.01 (P &lt; 0.05) and PWV and β increased from 3.9 ± 0.54 m/s and 1.86 ± 0.12 at rest to 5.75 ± 0.70 m/s and 3.25 ± 0.26 with exercise (P &lt; 0.05 for both), respectively. These results confirm increased MPA stiffness with exercise stress in both groups and the non-invasive metrics of MPA stiffness correlated well with β. Finally, as assessed by PWV but not RAC, PA stiffness of PH patients increased more than that of controls for comparable levels of moderate exercise.Conclusion: These results demonstrate the feasibility of using MRI for non-invasive assessment of exercise-induced changes in MPA stiffness in a small, heterogeneous group of PH patients in a research context. Similar measurements in a larger cohort are required to investigate differences between PWV and RAC for estimation of MPA stiffness