Search

Introduction/Background Individuals with cervical spinal cord injury experience tetraplegia with dramatic impairment of upper limb (UL) including hand function and decreased autonomy. In absence of very recent evidence and meta-analysis, we addressed UL rehabilitation effectiveness after tetraplegia. Material and method Two independent reviewers performed the systematic review and meta-analysis addressing Pubmed, Pedro, Central and Scopus®. We considered studies with a randomized controlled trial design, published in English language, which included individuals with tetraplegia and measured UL rehabilitation effect on strength, somesthesia, hand function and autonomy. Results From 573 records identified, 24 studies were included totaling 517 participants with C2 to C7 tetraplegia (ASIA A to D). Interventions lasted from 66 to 3780 minutes. Three different strategies were used i) bottom-up (namely massed practice, Functional Electrical Stimulation – FES, resistance or robotic training), ii) neuromodulation (i.e. electrical nerve, trans-cranial or magnetic stimulations), or iii) top-down (brain computer interfaces with FES or virtual reality). The 17 studies analyzed displayed heterogeneity for all outcomes except for strength. Overall, strength significantly increased with positive but non-significant effect on hand function and autonomy. Sub-analysis revealed a significant effect on strength only for bottom-up strategy. All other sub-analyzes albeit non-significant revealed at least a medium effect size for all outcomes with exception to the very small effect size displayed for somesthesia. Conclusion These results support the effectiveness of UL rehabilitation on strength using. There is a potential interest of using bottom-up and neuromodulation strategies to improve hand function and autonomy but with heterogeneity between interventions and participants. Conversely, there is no evidence for top-down strategy and interventions targeting somesthesia appear ineffective. Further effort on funding may promote high-quality multi-centric studies with increased standardization in intervention and participants to completely address UL rehabilitation effectiveness after tetraplegia while separating recovery and compensation effects.

Background: Evidence has recently emerged indicating that in addition to large airborne droplets, fine aerosol particles can be an important mode of influenza transmission that may have been hitherto underestimated. Furthermore, recent performance studies evaluating airborne infection isolation (AII) rooms designed to house infectious patients have revealed major discrepancies between what is prescribed and what is actually measured. Methods: We conducted an experimental study to investigate the use of high-throughput in-room air decontamination units for supplemental protection against airborne contamination in areas that host infectious patients. The study included both intrinsic performance tests of the air-decontamination unit against biological aerosols of particular epidemiologic interest and field tests in a hospital AII room under different ventilation scenarios. Results: The unit tested efficiently eradicated airborne H5N2 influenza and Mycobacterium bovis (a 4- to 5-log single-pass reduction) and, when implemented with a room extractor, reduced the peak contamination levels by a factor of 5, with decontamination rates at least 33% faster than those achieved with the extractor alone. Conclusion: High-throughput in-room air treatment units can provide supplemental control of airborne pathogen levels in patient isolation rooms.

To better understand the diffusion of Pneumocystis in the environment, airborne shedding of Pneumocystis carinii in the surrounding air of experimentally infected rats was quantified by means of a real-time polymerase chain reaction assay, in parallel with the kinetics of P. carinii loads in their lungs. P. carinii DNA was detected in the air 1 week after infection and increased until 4-5 weeks after infection before stabilizing. A significant correlation was shown between lung burdens and the corresponding airborne levels, suggesting the possibility of estimating the fungal lung involvement through quantification of Pneumocystis in the exhaled air.

We have studied the drainage of foams made from Newtonian and non-Newtonian solutions of different viscosities. Forced-drainage experiments first show that the behavior of Newtonian solutions and of shear-thinning ones (foaming solutions containing either Carbopol or Xanthan) are identical, provided one considers the actual viscosity corresponding to the shear rate found inside the foam. Second, for these fluids, a drainage regime transition occurs as the bulk viscosity is increased, illustrating a coupling between surface and bulk flow in the channels between bubbles. The properties of this transition appear different from the ones observed in previous works in which the interfacial viscoelasticity was varied. Finally, we show that foams made of solutions containing long flexible PolyEthylene Oxide (PEO) molecules counter-intuitively drain faster than foams made with Newtonian solutions of the same viscosity. Complementary experiments made with fluids having all the same viscosity but different responses to elongational stresses (PEO-based Boger fluids) suggest an important role of the elastic properties of the PEO solutions on the faster drainage.

Using the oscillating drop method as well as the interfacial stress rheometer (ISR), we measure the surface dilational and shear properties of adsorbed layers of oppositely charged polymer−surfactant complexes at the air−water interface. These data are compared to foam volume data measured for the corresponding solutions. We show that the shear surface moduli G‘ and G‘ ‘ exhibit a maximum at a molar ratio of polymer monomers and surfactant in solution equal to 1. This maximum is strongly correlated to surface ellipticity measurements that indicate a strong adsorption of polymer−surfactant complexes at the air−water interface. These hydrophobic interfacial complexes generate a viscoelastic layer due to the polymer chain entanglements and hydrophobic interactions between bound surfactant. The viscous behavior of the surface layers is further characterized via creep, frequency sweep measurements, and surface aging experiments. Over a 10 h period we find that G‘ and G‘ ‘ increase logarithmically with time, re...

Recent advances in our understanding of ‘complex fluids’ have lead to the development of new chemical additives in the agricultural industry, which provide more efficient products and a higher level of public and environmental protection. Here we present one example that deals with the improved application of herbicides and pesticides during the spray treatment of plants. Using judiciously chosen dilute polymer solutions, one can simultaneously improve the spray characteristics, droplet deposition, and product retention onto the targeted plant surface. Achieving these combined benefits, requires a delicate balance between fluid hydrodynamics and the molecular interactions that control the phase behaviour of the sprayed solutions. To cite this article: V. Bergeron, C. R. Physique 4 (2003).

This review is a topical survey of the forces and structures in thin liquid soap films. Included is a description of both the more classical forces, such as electrostatic double-layer and dispersion forces, together with new and emerging areas of research that cover so-called `supramolecular' forces. This latter category covers self-assembly of macromolecular structures confined in a thin-film region together with surface-induced adsorption of macromolecular complexes. In addition, recent extensions of the relation between thin-film forces and film stability are reviewed.

We directly measure, for the first time, disjoining pressure isotherms for asymmetric oil/aqueous surfactant/gas (i.e., pseudoemulsion) films using a modified version of the porous-plate technique first developed by Mysels in conjunction with thin-film interferometry. Dynamic film-thinning experiments are also performed on individual foam and pseudoemulsion films. At SDS surfactant concentrations above the critical micelle concentration (CMC) (0.1 M SDS), the pesudoemulsion films exhibit the same step-wise layer thinning observed in foam films under similar conditions. Further, we conduct dynamic thinning experiments on solid/liquid/gas systems and show that aqueous 0.2 M CTAB films sandwiched between glass and air also display discrete thinning transitions. All of these stratification transitions arise from oscillations in the disjoining pressure isotherm, generated by amphiphilic structuring within the film. For 0.1 M SDS dedecane/air pesudoemuslion films, the slope and peak height of the disjoining-pressure oscillations increase with each subsequent amphiphilic layer as film thickness decreases. Magnitudes of the structural forces are low (

Background Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD). Methods The study was carried out in 4 steps: i) patient room design, ii) CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii) construction of a prototype room and subsequent experimental studies to characterize its performance iv) qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF) open-source software Code_Saturne ® (http://www.code-saturne.org) was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations. Results We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes) can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to enter into the positive pressure room when the access door was opened, while 2°C had little effect. Based on these findings the constructed burn unit was outfitted with supplemental air exhaust ducts over the doors to compensate for the thermal convective flows. Conclusions CFD simulations proved to be a particularly useful tool for the design and optimization of a burn unit treatment room. Our results, which have been confirmed qualitatively by experimental investigation, stressed that airborne transfer of microbial size particles via thermal convection flows are able to bypass the protective overpressure in the patient room, which can represent a potential risk of cross contamination between rooms in protected environments.