Brain delivery of vasoactive intestinal peptide (VIP) following nasal administration to rats

The aim of this work was to study in rats the nasal route for the brain delivery of the vasoactive intestinal peptide (VIP) neuropeptide. After evaluating VIP stability in solutions obtained from nasal washes, the effect of formulation parameters (pH 4-9, 0-1% (w/v) lauroylcarnitine (LC), hypo- or isoosmolality) on the brain uptake of intranasally administered VIP (10(-8)M)/125I-VIP (300,000 cpm/ml) was studied, using an in situ perfusion technique. Brain radioactivity distribution was assessed by quantitative autoradiographic analysis. Results were compared to intravenously administered VIP. With a hypotonic formulation at pH 4 containing 0.1% LC and 1% bovine serum albumin, VIP stability was satisfactory and loss by adsorption was minimal. Using this formulation, around 0.11% of initial radioactivity was found in the brain after 30 min perfusion and was located in the olfactory bulbs, the midbrain and the cerebellum. HPLC analysis of brain and blood extracts demonstrated the presence of intact VIP in brain and its complete degradation in the blood compartment. By intravenous administration, no intact VIP was found either in brain or in blood. In conclusion, intact VIP could be delivered successfully to the brain using the intranasal route for administration

Designs of an organizational response to institutional complexity in healthcare: A focus group and statistical study of management control in French hospitals

This paper looks at hospitals' organizational structure through an institutional lens in order to examine how these organizations respond to the institutional complexity of the healthcare sector. Drawing on multiple and complementary sources of data, extracted from a focus group study, a statistical national database and a survey inquiry, we investigate one structural response of French hospitals to the emergence of a new managerial logic bringing more complexity in their field. We observe that this response, namely the implementation of management control systems, addresses this complexity by combining different institutional logics in a segmented system of actors, and that this arrangement of logics is not a strict homothetic translation of its correspondent field logic. We use the concept of hybridity to describe the distribution of institutional logics guiding organizational actors' behavior and conclude that cooperation within the system is related to the scope of action of most hybrid actors. We therefore contribute to the literature on institutional logics in healthcare by identifying organizational translation of field logics and hybrid actors' agency as key parameters in the structural design of hospitals' responses to institutional complexity

Semi-Implicit Roe-Type Fluxes for Low-Mach Number Flows

Two semi-implicit methods based on the splitting of the Euler equations flux into fluid and acoustic parts applied to low Mach number flows are presented. The first method is based on the splitting of slow and fast eigenvalues of the jacobian matrix of the fluxes and a semi-implicit scheme is constructed by introducing only the fast eigenvalues in the implicit matrices. The second method is based on the splitting of the Euler flux by separating the terms in velocity and the terms in pressure ; this system is solved by a fractional step method. A semi-implicit scheme is obtained by using a linearised implicit scheme for the acoustic step only. These two methods are applied to the convection of a density pulse for Mach numbers equal to 0.1 and 0.01. Accuracy and efficiency of the different schemes are compared

Consistent Regression using Data-Dependent Coverings

In this paper, we introduce a novel method to generate interpretable regression function estimators. The idea is based on called data-dependent coverings. The aim is to extract from the data a covering of the feature space instead of a partition. The estimator predicts the empirical conditional expectation over the cells of the partitions generated from the coverings. Thus, such estimator has the same form as those issued from data-dependent partitioning algorithms. We give sufficient conditions to ensure the consistency, avoiding the sufficient condition of shrinkage of the cells that appears in the former literature. Doing so, we reduce the number of covering elements. We show that such coverings are interpretable and each element of the covering is tagged as significant or insignificant. The proof of the consistency is based on a control of the error of the empirical estimation of conditional expectations which is interesting on its own

Faith Can Also Move Composite Gridshells

International audienceThis paper presents the overall design and construction process of a gridshell in composite materials at Créteil, in Paris suburb. This religious edifice of 350m² is a temporary cathedral meant to gather the parishioners during the two-years renovation of their permanent cathedral. It can accommodate up to 500 people and complies with all the required performances for such a building: structural stiffness, fire safety, waterproofness, lightning, thermal comfort, etc. This project arises thanks to a long-term collaboration between T/E/S/S and NAVIER and marks the accomplishment of a ten-years research project in the area

The Ephemeral Cathedral of Créteil : a 350m2 lightweight gridshell structure made of 2 kilometers of GFRP tubes

International audienceThe Ephemeral Cathedral of Créteil (Paris, France) is a gridshell structure made of composite materials. Built in 2013, this religious edifice of 350m 2 is a temporary church meant to gather the parishioners during the two-years renovation of their permanent cathedral. This large-scale prototype (Figure 1) represents a first in the building industry, which still shows excessive apprehension for the use of non-traditional materials such as composites, especially when it comes to structural applications. Based on a previous successful experience [1] the gridshell was prefabricated and erected by the parishioners themselves [2]

Construction of gridshells composed of elastically bended elements and covered by a streched three-dimensional membrane

International audienceThis document deals with the gridshells built by the Navier laboratory in the last ten years. The numerical conception is developed, from the draft made by architects up to the final structure. To design a gridshell several numerical tasks have to be performed. The geometry of the gridshell is first considered. Then, an iterative step mixing geometry and mechanical considerations is important. In particular, it is explained how the naturally straight beams are bended to form the final shape. This active bending provides many interests like high stiffness for a light weight structure. After the numerical design of the grid, the geometry of the membrane is drawn from the numerical final geometry of the gridshell. The improvements of gridshells, including safety considerations as well as practical considerations are then developed, trough the four gridshells recently built

From shape to shell: a design tool to materialize freeform shapes using gridshell structures

International audienceThis paper introduces and explains the design process of a gridshell in composite materials built in Paris in 2011 for the festival Soliday. A brief introduction presents the structural concept and the erection methodology employed. It explains why composite materials are relevant for such applications. Following this practical case, the whole process from 3D-shape to real-shell is then detailed. Firstly, the shape is rationalized and optimized to smooth local curvature concentrations. Secondly, a specific computing tool is used to mesh the surface according to the compass method. This tool allows designers to look for optimal mesh orientations regarding the elements curvature. Finally, a full structural analysis is performed to find the relaxed shape of the grid and check its stability, strength and stiffness under loads. The authors conclude on the overall relevance of such structures

La cathédrale éphémère de Créteil : une couverture ultra légère de 350m2 faite d'une résille de tubes composites en GFRP

National audienceThe Ephemeral Cathedral of Créteil (Paris, France) is a gridshell structure made of composite materials. Built in 2013, this religious edifice of 350m2 is a temporary church meant to gather the parishioners during the two-years renovation of their permanent cathedral. This large-scale prototype (Figure 1) represents a first in the building industry, which still shows excessive apprehension for the use of non-traditional materials such as composites, especially when it comes to structural applications. Based on a previous successful experience [1] the gridshell was prefabricated and erected [2] by the parishioners themselves.Le diocèse du Val de Marne a entrepris la rénovation de la cathédrale Notre Dame de Créteil. Pour la durée des travaux, une structure temporaire de type gridshell en GFRP – Glass Fibre Reinforced Polymer – qui permet d’assurer la continuité des célébrations religieuses, a été réalisée par le bureau d’études T/E/S/S et le laboratoire Navier sur la base d’une expérience antérieure réussie [1]. Cet article présente et détaille la conception et la construction de ce bâtiment (Figure 1) en place depuis 2 ans. Ce prototype de grande ampleur, construit par les paroissiens eux-mêmes [2], constitue une première dans le secteur de la construction qui reste encore très fermé à l’utilisation des matériaux non traditionnels, en particulier lorsqu’il s’agit d’applications structurelles