The colicin A lysis protein, Cal, is synthesized at the same time as colicin A by Escherichiu coli harbouring plasmid pColA after induction by mitomycin C. Its function in the induced bacteria involves the release of colicin A, quasi-lysis, the death of the producing cells and the activation of the outer membrane phospholipase A. We have found that these various functions are affected different...

We consider algebraic speciications with observational features. Axioms as well as observations are formulae of full (Many-Sorted) First Order Logic with Equality. The associated semantics is based on a non standard interpretation of equality called observational equality. We study the adequacy of this semantics for software specii-cation and the relationship with behavioural equivalence of alg...

Recent results in the chemistry of disubstituted carbenium ions (vinyl cations and phenyl cations) are described separately under three different sections: From kinetic and solvolytic data of several 1—cyclobutenyl nonaflates, the intermediacy of a non-classical vinyl cation, namely the 1-cyclobutenyl cation 2 is established. Cycloaddition reactions of solvolytically generated vinyl cations wit...

Azaoxyallyl cations represent a family of versatile and powerful synthetic synthons, which are generally in situ generated from a-halohydroxamates in the presence of organic or inorganic bases. Owing to the unique structural features and reactivities of azaoxyallyl cations, some various efforts have been made to enrich the synthetic methodology of azaoxyallyl cations (Scheme 1, 1). In 2011, Jef...

This paper generalizes the speci cation of Basic Interval Arithmetic Subroutines (BIAS) to support interval arithmetic on directed (i.e. proper and improper) intervals. This is due to our understanding that the arithmetic involving improper intervals will be increasingly used in future applications and the corresponding interval arithmetic implementations require no additional cost. We extend B...

The influence of polyvalent cations on the activation of end plate receptors has been studied in vitro on the sartorius muscle of the frog. In the absence of extracellular calcium, the sensitivity of the receptors to depolarizing quaternary ammonium salts was markedly reduced. Maximum receptor activation occurred in those fibers equilibrated in 1.8 m calcium Ringer solution, with the response b...

The standard approach to reasoning about polymorphic (also called recursive or self) methods is in terms of method reenement. That is, if the correctness of a (polymorphic) method f of class B depends on certain properties of another method g of B, then in any subclass of B in which g is redeened, the designer must make sure that g continues to exhibit these properties. While this allows the de...

Five metallic cations (Fe3+, Cr3+, Cal+, Mg2+, Mn2+; concentration range, 1.85 X 10-4 to 37 X 10-4 M) were incorporated individually as chlorides into nutrient broth and agar media used for the recovery of phenol-treated Escherichia coli. The effects observed varied with the concentration and the ionic species. In nutrient agar, Fe3+ and Cr3+ were generally beneficial but were toxic at 37 X 10-...

the aim of this study was to develop an extended-release tablet formulation using a new in situ cross-linking method. the effects of polyvalent cations on theophylline release from tablets made with the polyanionic polymers sodium alginate and sodium carboxymethylcellulose, were investigated. different miliequivalents of the di and tri-valent cation, ca2+ and al3+, were added to tablet formulat...