698 research outputs found

    A NOVEL HUMAN-IN-THE-LOOP TESTING FACILITY FOR SPACE APPLICATIONS

    Get PDF
    To analyse the interaction between the piloting astronaut and lunar lander dynamics while landing on the south pole of the moon, The European Space Agency (ESA) has initiated together with Thales Alenia Space (TAS), GMV Aerospace and Defence SAU (GMV) and The German Aerospace Centre (DLR) a project entitled “Human-In-the-Loop Flight Vehicle Engineering“. For this purpose, the DLR Robotic Motion Simulator (RMS) was transformed into a novel Humanin- the-Loop testing facility for space applications. The RMS represents a new class of motion simulators being currently developed at DLR that allow for extreme tilt angles and manoeuvres. It is based on an industrial 6 Degrees of Freedom (DOF) robot arm that is mounted onto a 10m long linear axis. The system therefore has a redundant 7 DOF architecture to induce motion cues onto an attached simulator cell. A highly modular simulator cell was configured for landing on the moon with three touch screens that were used to interact with the Human Machine Interface (HMI), Throttle and Joystick instruments, a virtual window to the outside, a headset and a surveillance camera for the piloting astronaut. The joystick features 3 DOFs and the throttle features adjustable damping along with many buttons that were used as inputs to the simulation. For the Moon landing scenery, a highresolution lunar crater visualization based on DLR’s Visualization 2 library was developed. Rocks and Boulders were distributed over the surface of the simulated region of the moon according to the Size-Frequency Distribution (SFD) for moon craters. ESA astronaut and test pilot Roberto Vittori tested various lunar landing manoeuvres using flight controls algorithms developed in HITL and motion simulation, provided by GMV, and was able to experience how the spacecraft behaves in critical phases of the lunar landing and intervene to control it. In one scenario the Landing GNC Automatic Mode was set to a landing zone where there were boulders. Vittori then had the option to intervene within a certain time window and, using touchscreens, select an alternative landing site. If needed, he was able to switch to Astronaut Manual Mode and pilot the lunar lander manually as it descended onto the lunar floor. Two Manual Control strategies were tested: Full Force / Torque Control and Rate Control. Two Motion cueing algorithms for low gravity environments were tested. Further experiments are planned

    Vitamin D Binding Protein, Total and Free Vitamin D Levels in Different Physiological and Pathophysiological Conditions.

    Get PDF
    This review focuses on the biologic importance of the vitamin D binding protein (DBP) with emphasis on its regulation of total and free vitamin D metabolite levels in various clinical conditions. Nearly all DBP is produced in the liver, where its regulation is influenced by estrogen, glucocorticoids and inflammatory cytokines but not by vitamin D itself. DBP is the most polymorphic protein known, and different DBP alleles can have substantial impact on its biologic functions. The three most common alleles-Gc1f, Gc1s, Gc2-differ in their affinity with the vitamin D metabolites and have been variably associated with a number of clinical conditions. Although DBP has a number of biologic functions independent of vitamin D, its major biologic function is that of regulating circulating free and total levels of vitamin D metabolites. 25 hydroxyvitamin D (25(OH)D) is the best studied form of vitamin D as it provides the best measure of vitamin D status. In a normal non-pregnant individual, approximately 0.03% of 25(OH)D is free; 85% is bound to DBP, 15% is bound to albumin. The free hormone hypothesis postulates that only free 25(OH)D can enter cells. This hypothesis is supported by the observation that mice lacking DBP, and therefore with essentially undetectable 25(OH)D levels, do not show signs of vitamin D deficiency unless put on a vitamin D deficient diet. Similar observations have recently been described in a family with a DBP mutation. This hypothesis also applies to other protein bound lipophilic hormones including glucocorticoids, sex steroids, and thyroid hormone. However, tissues expressing the megalin/cubilin complex, such as the kidney, have the capability of taking up 25(OH)D still bound to DBP, but most tissues rely on the free level. Attempts to calculate the free level using affinity constants generated in a normal individual along with measurement of DBP and total 25(OH)D have not accurately reflected directly measured free levels in a number of clinical conditions. In this review, we examine the impact of different clinical conditions as well as different DBP alleles on the relationship between total and free 25(OH)D, using only data in which the free 25(OH)D level was directly measured. The major conclusion is that a number of clinical conditions alter this relationship, raising the question whether measuring just total 25(OH)D might be misleading regarding the assessment of vitamin D status, and such assessment might be improved by measuring free 25(OH)D instead of or in addition to total 25(OH)D

    A Case of Hyperglycemic Hyperosmolar State Associated with Graves' Hyperthyroidism: A Case Report

    Get PDF
    Hyperglycemic hyperosmolar state (HHS) is an acute complication mostly occurring in elderly type 2 diabetes mellitus (DM). Thyrotoxicosis causes dramatic increase of glycogen degradation and/or gluconeogenesis and enhances breakdown of triglycerides. Thus, in general, it augments glucose intolerance in diabetic patients. A 23-yr-old female patient with Graves' disease and type 2 DM, complying with methimazole and insulin injection, had symptoms of nausea, polyuria and generalized weakness. Her serum glucose and osmolarity were 32.7 mM/L, and 321 mosm/kg, respectively. Thyroid function tests revealed that she had more aggravated hyperthyroid status; 0.01 mU/L TSH and 2.78 pM/L free T3 (reference range, 0.17-4.05, 0.31-0.62, respectively) than when she was discharged two weeks before (0.12 mU/L TSH and 1.41 pM/L free T3). Being diagnosed as HHS and refractory Graves' hyperthyroidism, she was treated successfully with intravenous fluids, insulin and high doses of methimazole (90 mg daily). Here, we described the case of a woman with Graves' disease and type 2 DM developing to HHS

    Genotype-Phenotype Correlation in 153 Adult Patients With Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency: Analysis of the United Kingdom Congenital Adrenal Hyperplasia Adult Study Executive (CaHASE) Cohort

    Get PDF
    CONTEXT: In congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, a strong genotype-phenotype correlation exists in childhood. However, similar data in adults are lacking. OBJECTIVE: The objective of the study was to test whether the severity of disease-causing CYP21A2 mutations influences the treatment and health status in adults with CAH. RESEARCH DESIGN AND METHODS: We analyzed the genotype in correlation with treatment and health status in 153 adults with CAH from the United Kingdom Congenital adrenal Hyperplasia Adult Study Executive cohort. RESULTS: CYP21A2 mutations were distributed similarly to previously reported case series. In 7 patients a mutation was identified on only 1 allele. Novel mutations were detected on 1.7% of alleles (5 of 306). Rare mutations were found on 2.3% of alleles (7 of 306). For further analysis, patients were categorized into CYP21A2 mutation groups according to predicted residual enzyme function: null (n = 34), A (n = 42), B (n = 36), C (n = 34), and D (n = 7). Daily glucocorticoid dose was highest in group null and lowest in group C. Fludrocortisone was used more frequently in patients with more severe genotypes. Except for lower female height in group B, no statistically significant associations between genotype and clinical parameters were found. Androgens, blood pressure, lipids, blood glucose, and homeostasis model assessment of insulin resistance were not different between groups. Subjective health status was similarly impaired across groups. CONCLUSIONS: In adults with classic CAH and women with nonclassic CAH, there was a weak association between genotype and treatment, but health outcomes were not associated with genotype. The underrepresentation of males with nonclassic CAH may reflect that milder genotypes result in a milder condition that is neither diagnosed nor followed up in adulthood. Overall, our results suggest that the impaired health status of adults with CAH coming to medical attention is acquired rather than genetically determined and therefore could potentially be improved through modification of treatment

    A cryptic record of Burgess Shale-type diversity from the early Cambrian of Baltica

    Get PDF
    Exceptionally preserved ‘Burgess Shale-type’ fossil assemblages from the Cambrian of Laurentia, South China and Australia record a diverse array of non-biomineralizing organisms. During this time, the palaeocontinent Baltica was geographically isolated from these regions, and is conspicuously lacking in terms of comparable accessible early Cambrian Lagerstätten. Here we report a diverse assemblage of small carbonaceous fossils (SCFs) from the early Cambrian (Stage 4) File Haidar Formation of southeast Sweden and surrounding areas of the Baltoscandian Basin, including exceptionally preserved remains of Burgess Shale-type metazoans and other organisms. Recovered SCFs include taxonomically resolvable ecdysozoan elements (priapulid and palaeoscolecid worms), lophotrochozoan elements (annelid chaetae and wiwaxiid sclerites), as well as ‘protoconodonts’, denticulate feeding structures, and a background of filamentous and spheroidal microbes. The annelids, wiwaxiids and priapulids are the first recorded from the Cambrian of Baltica. The File Haidar SCF assemblage is broadly comparable to those recovered from Cambrian basins in Laurentia and South China, though differences at lower taxonomic levels point to possible environmental or palaeogeographical controls on taxon ranges. These data reveal a fundamentally expanded picture of early Cambrian diversity on Baltica, and provide key insights into high-latitude Cambrian faunas and patterns of SCF preservation. We establish three new taxa based on large populations of distinctive SCFs: Baltiscalida njorda gen. et sp. nov. (a priapulid), Baltichaeta jormunganda gen. et sp. nov. (an annelid) and Baltinema rana gen. et sp. nov. (a filamentous problematicum)
    corecore