Université d'Orléans

The objective of this work is to use an economical diagnostic tool - chemiluminescence of NH2* - to give direct information on the H2 preferential diffusion effects in premixed ammonia-air flames.Abundant quantities of NH2* are produced in ammonia-air flames which makes it an interesting tracer of heat release, as stated in a previous study.Evidence of preferential diffusion was observed using a Bunsen-type burner and attributed to ammonia decomposition into hydrogen leading to preferential diffusion.In this study, new analyses based on addnl. experiments and simulations are proposed to support and quantify this hypothesis.Mixtures of equivalence ratios 0.9-1.4 have been investigated.With a Bunsen burner, we were unable to stabilize flames leaner than 0.9.The flow velocities required to stabilize these flames are very low (<0.2 m/s) due to the low flame speed of ammonia/air mixturesSpectroscopic and local chemiluminescence measurements of the flames were calibrated against a quartz-tungsten halogen lamp.The unique spectrum of each equivalence ratio depicting the reactivity of the flame was studied, and the ratio of two excited species: NH2*/OH* was used to provide a rough estimate of the equivalence ratio.This NH2*/OH* ratio was later applied to estimate the local equivalence ratio along the flame contour.Anal. of the NH2* profiles along the flame contour for various cases revealed changes in intensity and profile thickness, indicating the effects of H2 preferential diffusion.Relative lower intensities and thicker profiles of NH2* indicated a low reactivity and vice-versa.Since NH2* can be used as a good indicator, a sub-mechanism to predict these profiles has been proposed.The rate constants of pure collision reactions were determined using the collision theory, and the rate constant of the chemiluminescence reaction was determined exptl.Other involved reactions and species were identified using a sensitivity anal. on NH2 and NH2*.The proposed sub-mechanism was compared with the exptl. profiles, and the impact of the base mechanism has been stated.

This case report seeks to evaluate the effects of an osteopathic manipulative treatment (OMT) management and the advantages of optoelectronic plethysmography (OEP) for the quantification and description of asymmetrical chest wall motions associated with quality of life in a mild scoliosis patient (Cobb angle <30°).

A 72-year-old woman diagnosed with idiopathic scoliosis received three OMT associated with respiratory exercises in between treatment sessions. Respiratory kinematics and volumes were measured before and after each OMT session using OEP. Subjective patient's quality of life was estimated by completion of the Medical Outcomes Study Short Form 36 (SF-36) before the first and after the third interventions.

The OEP method assessed an asymmetrical motion of the pulmonary rib cage (RCP) and abdominal rib cage (RCA) between the left and right sides. This chest wall asymmetry seemed to be associated with the direction of the scoliosis deformity. The RCP and RCA asymmetry scores decreased gradually, approaching 0 % after OMT sessions, and their variability also decreased by the end of the protocol. Conversely, quality of life increased for all eight items evaluated, indicating positive effect of OMT in the management of this scoliosis patient who experienced chronic back pains.

Results from this single case study bring a promising method to evaluate non pharmacological intervention such as OMT in the management of idiopathic scoliosis patients. OEP is an effective method to evaluate breathing patterns in scoliosis patients and can detect respiratory asymmetries that could not have been objectified by any other method.

Concordia in Antarctica is one of the most remote and inhospitable inhabited places on the planet. Overwintering at Concordia presents extreme environmental conditions combining both physiological stress [three-month-long period of polar night (early May to early August) and three-month period of polar day (early November to early February), severe cold, and high-altitude hypoxia] and conditions of isolation and confinement known to induce both physical and cognitive alterations. However, given the very small number of subjects experiencing such conditions, literature remains scarce on the real impact of an overwintering period on steroid hormone changes. Using monthly records, we therefore assessed the impact of an overwintering in 23 male participants on awakening and evening concentrations of cortisol and testosterone, body composition and physical aptitude assessed using a Chester submaximal test. Across overwintering, 10 of the 23 subjects (Group 1) lost more than 2 % of their muscle mass. Awakening and evening concentrations of cortisol and testosterone were preserved throughout wintering with no significant deterioration in physical aptitude. However, Group 1 vs. Group 2 participants had higher end-exercise heart rate and lower testosterone fluctuations between awakening and evening (p < 0.05). These results highlighted the great adaptation of the hypothalamic-pituitary-adrenal and gonadal axis functions to long-term extreme polar exposure. Further studies are needed to determine the mechanisms underlying the alteration in muscle mass occurring in almost half of the winterers, taking into account the subjects' energy intake and expenditure as well as their initial physical aptitude, in order to propose effective diet and physical activity countermeasures.