Tetrodotoxin-Bupivacaine-Epinephrine Combinations for Prolonged Local Anesthesia

Currently available local anesthetics have analgesic durations in humans generally less than 12 hours. Prolonged-duration local anesthetics will be useful for postoperative analgesia. Previous studies showed that in rats, combinations of tetrodotoxin (TTX) with bupivacaine had supra-additive effects on sciatic block durations. In those studies, epinephrine combined with TTX prolonged blocks more than 10-fold, while reducing systemic toxicity. TTX, formulated as Tectin, is in phase III clinical trials as an injectable systemic analgesic for chronic cancer pain. Here, we examine dose-duration relationships and sciatic nerve histology following local nerve blocks with combinations of Tectin with bupivacaine 0.25% (2.5 mg/mL) solutions, with or without epinephrine 5 µg/mL (1:200,000) in rats. Percutaneous sciatic blockade was performed in Sprague-Dawley rats, and intensity and duration of sensory blockade was tested blindly with different Tectin-bupivacaine-epinephrine combinations. Between-group comparisons were analyzed using ANOVA and post-hoc Sidak tests. Nerves were examined blindly for signs of injury. Blocks containing bupivacaine 0.25% with Tectin 10 µM and epinephrine 5 µg/mL were prolonged by roughly 3-fold compared to blocks with bupivacaine 0.25% plain (P < 0.001) or bupivacaine 0.25% with epinephrine 5 µg/mL (P < 0.001). Nerve histology was benign for all groups. Combinations of Tectin in bupivacaine 0.25% with epinephrine 5 µg/mL appear promising for prolonged duration of local anesthesia

On the coupling of local 3D solutions and global 2D shell theory in structural mechanics

Most of mechanical systems and complex structures exhibit plate and shell components. Therefore, 2D simulation, based on plate and shell theory, appears as an appealing choice in structural analysis as it allows reducing the computational complexity. Nevertheless, this 2D framework fails for capturing rich physics compromising the usual hypotheses considered when deriving standard plate and shell theories. To circumvent, or at least alleviate this issue, authors proposed in their former works an in-plane-out-of-plane separated representation able to capture rich 3D behaviors while keeping the computational complexity of 2D simulations. However, that procedure it was revealed to be too intrusive for being introduced into existing commercial softwares. Moreover, experience indicated that such enriched descriptions are only compulsory locally, in some regions or structure components. In the present paper we propose an enrichment procedure able to address 3D local behaviors, preserving the direct minimally-invasive coupling with existing plate and shell discretizations. The proposed strategy will be extended to inelastic behaviors and structural dynamics

Parametric Shape and Material Simulations for Optimized Parts Design

In this paper we consider a parametric model related to the elasticity problem in which many parameter describing he material and/or the geometry will considered as extra-coordinates, allowing for the construction, from a single solution, of an abaqus containing the solution for each choice of the parameters considered as extra-coordinates. In order to circumvent the curse of dimensionality related to the high number of dimensions considered in the model, a separated representation will be considered.</jats:p

Experimental proof-of-concept of an energy ship propelled by a Flettner rotor

Abstract The energy ship is a new concept for offshore wind energy capture. It consists of a wind-propelled ship that generates electricity using water turbines attached underneath its hull. Since it is not grid-connected, the generated energy is stored aboard the ship (for instance, using batteries or through conversion to hydrogen using an electrolyser). This concept has received little attention until today. In this paper, a proof-of-concept of an energy ship propelled by a Flettner rotor is presented. The experimental results are compared to numerical simulations. A very good agreement is obtained, which validates previous numerical simulations that indicate that a full-scale energy ship equipped with Flettner rotors can lead to positive net energy production.</jats:p

Advanced simulation of models defined in plate geometries: 3D solutions with 2D computational complexity

International audienceMany models in polymer processing and composites manufacturing are defined in degenerated three-dimensional domains, involving plate or shell geometries. The reduction of models from 3D to 2D is not obvious when complex physics are involved. The hypotheses to be introduced for reaching this dimensionality reduction are sometimes unclear, and most of possible proposals will have a narrow interval of validity. The only getaway is to explore new discretization strategies able to circumvent or at least alleviate the drawbacks related to mesh-based discretizations of fully 3D models defined in plate or shell domains. An in-plane-out-of-plane separated representation of the involved fields within the context of the Proper Generalized Decomposition allows solving the fully 3D model by keeping a 2D characteristic computational complexity. Moreover the PGD features allow the introduction of many extra-coordinates, as for example the orientation of the different laminate plies, without affecting the solvability of the resulting multidimensional model