Nanorheology : an Investigation of the Boundary Condition at Hydrophobic and Hydrophilic Interfaces

t has been shown that the flow of a simple liquid over a solid surface can violate the so-called no-slip boundary condition. We investigate the flow of polar liquids, water and glycerol, on a hydrophilic Pyrex surface and a hydrophobic surface made of a Self-Assembled Monolayer of OTS (octadecyltrichlorosilane) on Pyrex. We use a Dynamic Surface Force Apparatus (DSFA) which allows one to study the flow of a liquid film confined between two surfaces with a nanometer resolution. No-slip boundary conditions are found for both fluids on hydrophilic surfaces only. Significant slip is found on the hydrophobic surfaces, with a typical length of one hundred nanometers.Comment: 8 pages, 7 figures, 2 tables. Accepted for European Physical Journal E - Sofr Mate

Clinical Effectiveness of Transversus Abdominis Plane (TAP) Block versus Local Anesthesia Wound Infiltration for Postoperative Pain Relief After Laparoscopic Appendicectomy in Children: A Study Protocol for a Multicenter Double-Blind Randomized Controlled Phase III Trial

Geoffrey Bloy,1 Amelie Jurine,1 Yann Chaussy,2 Frederic Auber,2 Pierre-Gregoire Guinot,3 Belaid Bouhemad,3 Michel Francois,4 Lucie Vettoretti,1 Sebastien Pili-Floury,5 Maxime Nguyen,3 Guillaume Besch5 1CHU Besançon, Département d’Anesthésie Réanimation Chirurgicale, Besançon, F-25000, France; 2Université de Franche-Comté, CHU Besançon, SINERGIES, Service de Chirurgie Pédiatrique, Besançon, F-25000, France; 3University of Burgundy and Franche-Comté, Dijon University Hospital, INSERM LNC UMR1231, FCS Bourgogne Franche-Comté LipSTIC LabEx, Dijon, F-21000, France; 4Université de Bourgogne, CHU Dijon, Service de Chirurgie Pédiatrique, Dijon, F-21000, France; 5Université de Franche-Comté, CHU Besançon, SINERGIES, Département d’Anesthésie Réanimation Chirurgicale, Besançon, F-25000, FranceCorrespondence: Guillaume Besch, Département d’Anesthésie Réanimation Chirurgicale, CHU Besançon, 3 bvd Alexandre Fleming, Besançon, 25030, France, Tel +3381218958, Fax +3381669331, Email [email protected]: Postoperative pain relief after laparoscopic appendicectomy is a key determinant of early rehabilitation in children. Recent guidelines recommend performing either a transversus abdominis plane (TAP) block or local anesthesia (LA) wound infiltration as part of multimodal postoperative analgesia after appendectomy. To date, the clinical effectiveness of TAP block versus LA wound infiltration has never been compared. The hypothesis of this study is that the TAP block may provide a greater opioid-sparing effect after laparoscopic appendicectomy in children than LA wound infiltration.Study Design and Methods: We designed a multicenter double-blind randomized controlled phase III trial and aim to include 110 children who undergo laparoscopic appendicectomy. Children are randomized to receive either TAP block (TAP group) or LA wound infiltration (infiltration group). Multimodal analgesia is standardized in the two groups using the same protocol, which includes the stepwise prescription of paracetamol, phloroglucinol, ketoprofene, and nalbuphine according to the hetero-evaluation of pain performed by the nurses who were blinded to the treatment allocated using the validated FLACC scale. The primary outcome is the total dose of nalbuphine administered within 24 hours after surgery.Discussion: No study has specifically compared the clinical effectiveness of TAP block versus LA wound infiltration for postoperative pain relief after laparoscopic appendectomy in children. This paper describes the protocol for a randomized trial that addresses this issue. The results of this trial will be useful for editing guidelines with a higher level of evidence on this topic.Keywords: laparoscopic appendectomy, TAP block, wound infiltration, analgesia, childre

Thin oceanic crust and flood basalts: India-Seychelles breakup

Recent seismic experiments showed that separation of India from the Seychelles occurred in two phases of rifting. The first brief phase of rifting between India and the Laxmi Ridge formed the Gop Rift, which is characterized by thick oceanic crust and underplating of the adjacent continental margins. The age of the Gop Rift is uncertain, initiation of seafloor spreading being some time between 71 and 66 Ma. This was then followed by rifting and seafloor spreading between the Laxmi Ridge and the Seychelles, the onset of which is well dated by magnetic anomalies at 63.4 Ma and characterized by thin oceanic crust. Both of these rift events occurred within 1000 km of the center of the Deccan flood basalts, which formed at 65 ± 1 Ma. To constrain the age of the Gop Rift and to explore the reasons for the change in crustal structure between the Gop Rift and Seychelles-Laxmi Ridge margins, we employ a geodynamic model of rift evolution in which melt volumes, seismic velocity, and rare earth element (REE) chemistry of the melt are estimated. We explore the consequences of different thermal structures, hydration, and depletion on the melt production during the India-Seychelles breakup to understand the reasons behind the thin oceanic crust observed. Magmatism at the Gop Rift is consistent with a model in which the seafloor spreading began at 71 Ma, ca. 6 Myr prior to the Deccan. The opening occurred above a hot mantle layer (temperature of 200°C, thickness of 50 km) that we interpret as incubated Deccan material, which had spread laterally beneath the lithosphere. This scenario is consistent with observed lower crustal seismic velocities of 7.4 km s?1 and 12 km igneous crustal thickness. The model indicates that when the seafloor spreading migrated to the Seychelles-Laxmi Ridge at 63 Ma, the thermal anomaly was reduced significantly but not sufficient to explain the observed reduction in breakup magmatism. From observations here of 5.2 km oceanic crust, lower crustal seismic velocities of 6.9 km s?1 and a flat REE profile, we infer that breakup occurred in a region of mantle that became depleted by prior extension related to the Gop Rift