Flectofin: a hingeless flapping mechanism inspired by nature.

This paper presents a novel biomimetic approach to the kinematics of deployable systems for architectural purposes. Elastic deformation of the entire structure replaces the need for local hinges. This change becomes possible by using fibre-reinforced polymers (FRP) such as glass fibre reinforced polymer (GFRP) that can combine high tensile strength with low bending stiffness, thus offering a large range of calibrated elastic deformations. The employment of elasticity within a structure facilitates not only the generation of complex geometries, but also takes the design space a step further by creating elastic kinetic structures, here referred to as pliable structures. In this paper, the authors give an insight into the abstraction strategies used to derive elastic kinetics from plants, which show a clear interrelation of form, actuation and kinematics. Thereby, the focus will be on form-finding and simulation methods which have been adopted to generate a biomimetic principle which is patented under the name Flectofin®. This bio inspired hingeless flapping device is inspired by the valvular pollination mechanism that was derived and abstracted from the kinematics found in the Bird-Of-Paradise flower (Strelitzia reginae, Strelitziaceae).

Effects of ifenprodil and baclofen on exercise-induced increase of myocardial oxygen demand in normotensive rats.

Central glutamatergic relays are known to be present in the central sympathetic pathways. Ifenprodil (an N-methyl-D-aspartate antagonist) and baclofen (a gamma-aminobutyric acid(B) agonist) are both modulators of these synapses; we previously reported their ability to reduce the cardiovascular responses induced by a central hypothalamic stimulation in rabbits. In this work, we investigated the actions of chronic treatments with these two drugs on the increase of myocardial oxygen demand induced by exercise in normotensive rats. Moreover, their effects on the baroreceptor heart rate reflex were observed. Male normotensive WKY rats were treated with placebo (two groups), baclofen, or ifenprodil for 14 days. They were then submitted to a progressively increased exercise test on a treadmill. In another three groups of animals, the same treatment was applied but, at the end, a baroreflex study was performed by the injection of phenylephrine (vagal component of the reflex) and of sodium nitroprusside (sympathetic component). Ifenprodil and baclofen reduced by nearly 50% the level of the increase of the rate x pressure product during exercise as compared with control rats. This effect appeared to be mainly due to a reduction of the hypertensive response. In the same conditions, neither baclofen nor ifenprodil significantly altered the baroreceptor heart rate reflex. The fact that these two drugs are capable of reducing the myocardial oxygen demand encourages us to test them in a model of myocardial ischemia associated with sympathetic hyperactivity.

Characteristics of rapid eye movement production during REM sleep in man: organization and rhythmicity.

The purpose of this study was to verify statistically the existence of certain characteristics of rapid eye movement (REM) production during REM sleep: organization and rhythmicity. REM data were collected intermittently, over a period of 20 consecutive nights, from 6 normal adult subjects of both sexes. Results concerning the organization of REM production revealed the presence of 3 evolving slow trends: quadratic, linear and quasi-sinusoidal. The occurrence of a given trend type was not related to subject, night, time of night or length of REM sleep phase being analysed. Results of the analysis showed that it is possible for a series of REMs to contain one, two or more statistically significant rhythmic periods, or no significant rhythmic period. The rhythmic periods that were detected ranged from 1 to 21 min, and no predominant periods were present. As in the case of the slow trends, the occurrence of a given rhythmic period was not dependent on subject, night, time of night or length of the REM sleep phase.

[Preliminary study on the resumption of work after aorto-coronary bypass]. / Etude préliminaire sur la reprise du travail après pontage aorto-coronarien.

A questionnaire was sent 8 months to 3 years after aorto-coronary bypass to 98 patients who, before surgery, had had to abandon their professional activities because of ischaemic heart disease to assess the numbers who had returned to work: thirty six patients (37%) had not returned to work for medical or personal reasons; only one patient had been refused by his employee; sixty two patients (63%) had returned to work, 81% full-time and 19% with a different job. Only 19% had to stop working secondarily for medical reasons. The criteria thought initially to influence the chances of resumption of professional activity were analysed: factors not influencing the return to work were: type of work before operation (judged by the physical activity involved and the statute of salaried or independent worker), the severity of surgery (number of grafts and associated resection of aneurysm), a subjective assessment of physical condition after surgery (91% or patients not returning to work admitted to feeling well); uncontrollable factors influencing the return to work were: age of patient (average 51,7 years for those returning to work, compared to 55,1 years for the others), previous history of myocardial infarction (2,5 times more common in those not returning to work); finally, controllable factors influencing return to work were: the duration of unemployment before surgery (3,3 months for those returning full-time, compared to 16,4 months for those not returning to work); the period between surgery and resumption of activity which averaged 5 months and should not exceed 6 months. Three factors seemed to be particularly important: apart from the shortest possible period of unemployment before surgery, early physical reeducation after surgery based on chest physiotherapy and readaptation to physical activity and a psychological preparation for the return to work which should be started even before surgery.