An Efficient Stochastic Constrained Path Planner for Redundant Manipulators

This brief proposes a novel stochastic method that exploits the particular kinematics of mechanisms with redundant actuation and a well-known manipulability measure to track the desired end-effector task-space motion in an efficient manner. Whilst closed-form optimal solutions to maximise manipulability along a desired trajectory have been proposed in the literature, the solvers become unfeasible in the presence of obstacles. A manageable alternative to functional motion planning is thus proposed that exploits the inherent characteristics of null-space configurations to construct a generic solution able to improve manipulability along a task-space trajectory in the presence of obstacles. The proposed Stochastic Constrained Optimization (SCO) solution remains close to optimal whilst exhibiting computational tractability, being an attractive proposition for implementation on real robots, as shown with results in challenging simulation scenarios, as well as with a real 7R Sawyer manipulator, during surface conditioning tasks.

Physiological adaptations affecting drug pharmacokinetics in space: what do we really know? A critical review of the literature.

As human spaceflight continues with extended mission durations, the demand of effective and safe drugs is going to increase. To date, the medications used during missions (for space motion sickness, sleep disturbances, allergies, pain and sinus congestion) are administered under the assumption that they act similarly as on the Earth. During spaceflights however fluid shifts, muscle and bone loss, immune system dysregulation and changes in the gastrointestinal tract and metabolism are documented. These alterations may change the pharmacokinetics (PK) and pharmacodynamics. The information gained from bed-rest studies and from inflight observations is partial and demonstrates variability in drug PK. The objectives of this review are to report: i) the impact of the space environmental stressors on human physiology in relation to PK; ii) the state-of-the-art on experimental data in space and/or in ground-based models; iii) the validation of ground-based models for PK studies; and iv) the identification of possible research gaps.

Influence of Inosine on Cerebral Hemodynamics in Space Motion Sickness in Experimental Animals

Background: Motion sickness occurs worldwide in healthy individuals regardless of age, ethnicity, or gender. It is an acute disorder, it can also present as a chronic disorder in some individuals. Motion sickness not only includes vomiting and nausea, besides this, it includes other features such as pallor of varying degrees, cold sweating, headache, drowsiness, increased salivation, and cranial pain which is severe. Some of the other assessment scales can interpret sickness on exposure to virtual or visual stimulation and while travelling in different types of transport. Aim: The aim our research is to study the effect of the drug on the level of blood flow and vascular reactivity of cerebral vessels when simulating changes in cerebral circulation in terrestrial conditions characteristic of hypogravity. Methods: Chronic experiments were performed on non-anesthetized rabbits with large hemispheres, thalamus and hypothalamus were implanted with the needle-platinum electrodes 150 mm in diameter in the cortex, and local blood flow and vascular reactivity were recorded accordingly. Cerebrovascular disturbances were modeled using a MSAOP (motion sickness of animals in the anti-orthostatic position) with an inclined angle of 45 ° for 2 hours. Local blood flow (BF) was measured in ml/min/100 g of tissue by the method of registration of hydrogen clearance. The vasodilator coefficient of reactivity (CrCO2) was calculated by the ratio of BF against the background of inhalation of a mixture of 7% CO2 with air to the initial BF; vasoconstrictor - in relation to BF on the background of inhalation of 100% O2 to the initial BF (CrO2). A series of experiments was carried out with different routes of drug administration: First, inosine was administered intravenously at a dose of 5 mg/kg immediately before the start of SMS modeling, Same dose per oral was administered 30 minutes before the start of exposure. As a control, we used the results of experimental animals under similar conditions without the administration of the drugs. Results: Inosine has pronounced protective properties in cerebrovascular disorders on the background of space motion sickness (SMS) modeling, which is manifested by normalization of BF and restoration of compensatory reactions of cerebral vessels. In the mechanism of cerebroprotective action of inosine, it is able to correct the metabolic processes which plays an important role and helps to increase the compensatory capabilities and functional stability of the cerebrovascular system under gravitational influences. Conclusion: When using inosine per orally, the effects are more pronounced than when administered intravenously, which should be taken into account when using it for the prevention of cerebrovascular disorders in extreme conditions.

Subtypes of Persistent Postural-Perceptual Dizziness

Background: Persistent postural-perceptual dizziness (PPPD) is a persistent chronic vestibular syndrome exacerbated by upright posture/walking, active or passive motion, and exposure to moving or complex visual stimuli. PPPD has four precursors: phobic postural vertigo, space-motion discomfort, visual vertigo, and chronic subjective dizziness. These four diseases share clinical features that form the basis of the diagnostic criteria for PPPD. Semiological similarities do not necessarily mean that PPPD is a single entity. However, if PPPD is not a single disorder but just a composite of four precursors, it may be subdivided according to the characteristics of each precursor.Objective: To test whether PPPD is a single disorder, we attempted a subtyping of PPPD.Methods: One-hundred-eight untreated patients with PPPD were enrolled in the study, who filled out the Niigata PPPD Questionnaire (NPQ) that consists of 12 questions on exacerbating factors for PPPD. A factor analysis of the patients' answers to the NPQ and a subsequent cluster analysis of the patients with PPPD using factors revealed by the factor analysis were performed. To validate our cluster classification, cluster differences were assessed using analysis of variance. Multiple comparison analyses were performed on demographical data, precipitating diseases, the Dizziness Handicap Inventory, the Hospital Anxiety and Depression Scale, and several vestibular tests to characterize each cluster.Results: Factor analysis revealed three underlying factors among the exacerbating factors in the NPQ. Exacerbation by visual stimuli (visual factor) accounted for 47.4% of total variance in the questionnaire. Exacerbation by walking/active motion (active-motion factor) and by passive motion/standing (passive-motion/standing factor) accounted for 12.0 and 7.67% of variance, respectively. Cluster analysis revealed three clusters: the visual-dominant subtype (n = 49); the active motion-dominant subtype (n = 20); and the mixed subtype (n = 39). The patients in the active motion-dominant subtype were significantly older than those in the visual-dominant subtype. There were no significant differences among the subtypes in other demographical data or conventional vestibular tests.Conclusions: The most common main exacerbating factor of PPPD was the visual factor. PPPD may be categorized into three subtypes. Conventional vestibular tests failed to point the characteristics of each subtype.

Brief Analysis of the Visual Language of Digital Animation

Digital animation is a new form of artistic expression of animation, which fully coincides with the cultural atmosphere and social context of pursuing visual perception in modern art. The visual language takes color, shape, space, motion as communication means to make appropriate expression in a specific context and carry out specific information transmission. Therefore, digital animation is not only an artistic product, but also a trend of visual communication exploration. It combines science and technology with art, providing more possibilities for artistic creation. This paper takes the visual language as the main line and attempts to explore the characteristics, performance and formation mechanism of digital animation.

Weitere Studien für klare klinische Empfehlungen notwendig

Astronauten berichten im Rahmen von Raumflügen über Symptome im Sinne von Kinetosen (engl. „(Space) Motion Sickness“), welche innerhalb der ersten 72 Stunden in der Schwerelosigkeit zu teils deutlicher Beeinträchtigung führen 1. Zur Erforschung der Auswirkungen von Schwerelosigkeit werden Parabelflüge durchgeführt, um den Effekt der Mikrogravitation zu untersuchen 2. Auch hierbei leiden die der Schwerelosigkeit ausgesetzten Menschen unter ähnlichen Beschwerden. Die Autoren der vorgestellten Studie versuchen, beobachtend anhand von 246 Parabelflugberichten, das Problem der assoziierten Kinetosen zu erfassen und prädiktive sowie modifizierende Faktoren zu identifizieren.