The recently chemically synthesized Escherichia coli lipid A and the natural free lipid A of E. coli were compared with respect to their endotoxic activities in the following test systems: lethal toxicity, pyrogenicity, local Shwartzman reactivity, Limulus amoebocyte lysate gelation capacity, tumour necrotizing activity, B cell mitogenicity, induction of prostaglandin synthesis in macrophages, and antigenic specificity. It was found that synthetic and natural free lipid A exhibit identical activities and are indistinguishable in all tests.Lipopolysaccharides (endotoxins) of gram-negative bacteria which consist of a heteropolysaccharide and a lipid component (termed lipid A) elicit multiple acute pathophysiological effects such as fever, lethality, Shwartzman reactivity, macrophage and B-lymphocyte activation, and other activities [I]. In 1954 it was proposed that for the induction of these effects the polysaccharide portion is dispensable and that the lipid A component represents the active center responsible for the endotoxic properties of lipopolysaccharides [2]. Evidence for this was then obtained in numerous investigations [2 -41 and this concept is now generally accepted.The chemical structure of the lipid A component of several enterobacterial lipopolysaccharides has been analysed during recent years in great detail (for reviews see [5, 61) and it was recognized that lipid A of Escherichiu coli possesses a comparatively simple structure. Free E. coli lipid A consists of a 8(1-6)-linked D-glucosamine disaccharide which is substituted by two phosphoryl groups, one being bound to position 4' of the nonreducing glucosamine residue (GlcN 11) and one being a-linked [7] to the glycosidic hydroxyl group of the reducing glucosaminyl group (GlcN I) (Fig.
Part I of this paper introduced a Lagrangian variational formulation for the nonequilibrium thermodynamics of discrete systems. This variational formulation extends the Hamilton principle to allow the inclusion of irreversible processes in the dynamics. The irreversibility is encoded into a nonlinear nonholonomic constraint given by the expression of entropy production associated to all the irreversible processes involved. In Part II, we develop this formulation for the case of continuum systems by extending the setting of Part I to infinite dimensional nonholonomic Lagrangian systems. The variational formulation is naturally expressed in material representation, while its spatial version is obtained via a nonholonomic Lagrangian reduction by symmetry. The theory is illustrated with the examples of a viscous heat conducting fluid and its multicomponent extension including chemical reactions and mass transfer.
In this paper, we present a Lagrangian variational formulation for nonequilibrium thermodynamics. This formulation is an extension of the Hamilton principle in classical mechanics that allows the inclusion of irreversible phenomena. The irreversibility is encoded into a nonlinear phenomenological constraint given by the expression of entropy production associated to all the irreversible processes involved. Hence from a mathematical point of view, our variational formulation may be regarded as a generalization of the Lagrange-d'Alembert principle used in nonlinear nonholonomic mechanics to the nonequilibrium thermodynamics, where the conventional Lagrange-d'Alembert principle cannot be applied since the nonlinear phenomenological constraint and its associated variational constraint must be separately treated. In our approach, to deal with the nonlinear nonholonomic constraint, we introduce a variable called the thermodynamic displacement associated to each irreversible process. This allows us systematically to define the corresponding variational constraint. In Part I, our variational theory is illustrated with various examples of discrete systems such as mechanical systems with friction, matter transfer, electric circuits, chemical reactions, and diffusion across membranes. In Part II of the present paper, we will extend our variational theory of discrete systems to the case of of continuum systems. Contents 1 Introduction 2 2 Some preliminaries 5 3 Variational formulation for nonequilibrium thermodynamics of simple systems 9 3.
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