Extrusion: A New Method for Rapid Formulation of High-Yield, Monodisperse Nanobubbles

Shell-stabilized gas microbubbles (MB) and nanobubbles (NB) are frequently used for biomedical ultrasound imaging and therapeutic applications. While it is widely recognized that monodisperse bubbles can be more effective in these applications, the efficient formulation of uniform bubbles at high concentrations is difficult to achieve. Here, it is demonstrated that a standard mini-extruder setup, commonly used to make vesicles or liposomes, can be used to quickly and efficiently generate monodisperse NBs with high yield. In this highly reproducible technique, the NBs obtained have an average diameter of 0.16 ± 0.05 µm and concentration of 6.2 ± 1.8 × 1010 NBs mL−1 compared to 0.32 ± 0.1 µm and 3.2 ± 0.7 × 1011 mL−1 for NBs made using mechanical agitation. Parameters affecting the extrusion and NB generation process including the temperature, concentration of the lipid solution, and the number of passages through the extruder are also examined. Moreover, it is demonstrated that extruded NBs show a strong acoustic response in vitro and a strong and persistent US signal enhancement under nonlinear contrast enhanced ultrasound imaging in mice. The extrusion process is a new, efficient, and scalable technique that can be used to easily produce high yield smaller monodispersed nanobubbles

Produire de l’ignorance plutôt que du savoir ?

Cet article analyse les effets du recours croissant à l’expertise scientifique dans l’élaboration et la mise en œuvre des politiques de santé au travail. S’appuyant sur des exemples (valeurs limites et fractions attribuables) abordés lors d’un séminaire interdisciplinaire organisé en 2014-2015, il montre comment l’adoption d’un outil de mesure ou de régulation issu de disciplines biomédicales induit des points aveugles dans la définition et la prise en charge d’un enjeu. Il analyse également à partir d’autres exemples les effets plus indirects de cette évolution, qui limite les possibilités d’intervention des organisations syndicales. Il invite aussi à s’interroger sur la place des sciences humaines et sociales et des savoirs de terrain, notamment dans la mise au jour des dimensions conflictuelles de ces enjeux, souvent occultées par l’expertise institutionnelle. Il propose enfin l’ouverture aux non-spécialistes d’un large débat politique sur les questions collectives de santé au travail, rendu plus difficile par leur définition en termes technoscientifiques.This paper analyses the consequences of the increasing reference to scientific expertise in the decision and implementation process of occupational health policy. Based on examples (exposure limits and attributable fractions) taken from an interdisciplinary seminar conducted in 2014-2015, it shows how the measurement or regulation of a problem through biomedical sciences produces blind spots. More indirect implications are also examined through other examples, such as the limitation of trade unions’ scope for action. The potential contribution of social sciences and field knowledge is also questioned, notably to uncover the conflicting dimensions of such issues, often rendered invisible by institutional norms of expertise. Finally, the paper suggests launching a broad political debate accessible to non-specialists about collective occupational health issues, a dialogue made difficult by the rise of the afore-mentioned techno-scientific perspective

Emergency department sternotomy - report of a case with indications and technique overview

The Emergency Department thoracotomy and Emergency Department sternotomy are solutions of the last resort for traumatic cardiorespiratory arrest. Time is the most important factor in terms of survival and sparing potential neurological damage, therefore surgery should not be delayed as it can be done in an emergency room, intensive care unit or in the operating room. We will present a case of a 45-year-old man with a knife stab in his chest and cardiorespiratory arrest during transport in ambulance. Upon arrival at the Emergency Department, sternotomy was performed followed by decompressive pericardiotomy and cardiorrhaphy with successful and uneventful recovery. We will discuss the indications, necessary equipment and surgical technique

Produire de l’ignorance plutôt que du savoir ?

Cet article analyse les effets du recours croissant à l’expertise scientifique dans l’élaboration et la mise en œuvre des politiques de santé au travail. S’appuyant sur des exemples (valeurs limites et fractions attribuables) abordés lors d’un séminaire interdisciplinaire organisé en 2014-2015, il montre comment l’adoption d’un outil de mesure ou de régulation issu de disciplines biomédicales induit des points aveugles dans la définition et la prise en charge d’un enjeu. Il analyse également à partir d’autres exemples les effets plus indirects de cette évolution, qui limite les possibilités d’intervention des organisations syndicales. Il invite aussi à s’interroger sur la place des sciences humaines et sociales et des savoirs de terrain, notamment dans la mise au jour des dimensions conflictuelles de ces enjeux, souvent occultées par l’expertise institutionnelle. Il propose enfin l’ouverture aux non-spécialistes d’un large débat politique sur les questions collectives de santé au travail, rendu plus difficile par leur définition en termes technoscientifiques.This paper analyses the consequences of the increasing reference to scientific expertise in the decision and implementation process of occupational health policy. Based on examples (exposure limits and attributable fractions) taken from an interdisciplinary seminar conducted in 2014-2015, it shows how the measurement or regulation of a problem through biomedical sciences produces blind spots. More indirect implications are also examined through other examples, such as the limitation of trade unions’ scope for action. The potential contribution of social sciences and field knowledge is also questioned, notably to uncover the conflicting dimensions of such issues, often rendered invisible by institutional norms of expertise. Finally, the paper suggests launching a broad political debate accessible to non-specialists about collective occupational health issues, a dialogue made difficult by the rise of the afore-mentioned techno-scientific perspective

Influence de la dépendance au champ visuel dans la construction et le maintien d'une posture verticale inversée en milieux terrestres et aquatiques

La contribution relative des différentes entrées sensorielles dans le contrôle postural a souvent été étudiée dans le cadre de la posture érigée fondamentale. L objectif de nos travaux a été de déterminer cette contribution dans deux postures relativement proches dans leur configuration : l appui tendu renversé (ATR) et la verticale inversée (VI) en milieu aquatique. Si la vision est souvent considérée comme information principale dans le contrôle postural de la station érigée, la configuration structurelle (champ visuel restreint en ATR, immersion de l œil en VI) de ces deux postures laisse imaginer un fonctionnement différent. La perturbation des différents capteurs sensoriels impliqués dans le contrôle postural a permis d observer la réorganisation mise en place par le système nerveux central (SNC) pour y remédier. De plus la prise en compte d un facteur perceptif comme la dépendance au champ visuel nous a paru être un élément pertinent pour tenter d observer d éventuelles différences interindividuelles dans les comportements des sujets. La perturbation du contrôle postural a été évaluée au travers d une analyse cinématique et d une analyse stabilométrique de l ATR (analyse classique et non-linéaire). Les résultats de ces analyses laissent entrevoir des différences de stratégie entre les sujets dépendants et indépendants au champ visuel dans le contrôle de l appui tendu renversé, ce qui ne semble pas être le cas en verticale inverséeThe relative contribution of the different sensory inputs in erect postural control has often been studied. The aim of this work is to determine this contribution in two positions relatively close in their configuration: the handstand and the upside-down posture in water. If vision is often considered as the main information in postural control, the structural configuration (restricted visual field in handstand, eye s immersion in upside-down posture) of these two postures lets imagine a different operation. Disruption of sensory receptors involved in postural control has allowed observing the reorganization implemented by the central nervous system (CNS). In addition, the visual field dependence appeared to be a relevant factor to observe interindividual behavioral differences. Disturbance of postural control was assessed through a kinematic analysis and a stabilometric analysis of the handstand (classical analysis and non-linear analysis). Results of these analyzes suggest different strategy according to visual field dependence in the control of the handstand, which does not seem to be the case in upside-down posturePARIS5-Bibliotheque electronique (751069902) / SudocSudocFranceF

Ferromagnetic resonance study of sputtered Co|Ni multilayers

We report on room temperature ferromagnetic resonance (FMR) studies of [$t$ Co$|2t$ Ni]$\times$N sputtered films, where $0.1 \leq t \leq 0.6$ nm. Two series of films were investigated: films with same number of Co$|$Ni bilayer repeats (N=12), and samples in which the overall magnetic layer thickness is kept constant at 3.6 nm (N=1.2/$t$). The FMR measurements were conducted with a high frequency broadband coplanar waveguide up to 50 GHz using a flip-chip method. The resonance field and the full width at half maximum were measured as a function of frequency for the field in-plane and field normal to the plane, and as a function of angle to the plane for several frequencies. For both sets of films, we find evidence for the presence of first and second order anisotropy constants, $K_1$ and $K_2$. The anisotropy constants are strongly dependent on the thickness $t$, and to a lesser extent on the total thickness of the magnetic multilayer. The Land\'e g-factor increases with decreasing $t$ and is practically independent of the multilayer thickness. The magnetic damping parameter $\alpha$, estimated from the linear dependence of the linewidth, $\triangle H$, on frequency, in the field in-plane geometry, increases with decreasing $t$. This behaviour is attributed to an enhancement of spin-orbit interactions with $t$ decreasing and in thinner films, to a spin-pumping contribution to the damping.Comment: 18 pages, 13 figure

High Momentum Probes of Nuclear Matter

We discuss how the chemical composition of QCD jets is altered by final state interactions in surrounding nuclear matter. We describe this process through conversions of leading jet particles. We find that conversions lead to an enhancement of kaons at high transverse momentum in Au+Au collisions at RHIC, while their azimuthal asymmetry v_2 is suppressed.Comment: Contribution to the 4th international workshop High-pT physics at LHC 09, Prague; 6 pages, 6 figure