Isothermal titration calorimetry of Ni(II) binding to histidine and to N-2-aminoethylglycine

Isothermal titration calorimetry (ITC) is used to study the complexation thermodynamics of Ni(II) with histidine (His) and with N-2-aminoethylglycine (EDMA). The titrations were performed in HEPES and Tris buffers at various ionic strengths and pH values around 8. The results show the influence of the experimental conditions on the shape and fitting parameters of the calorimetric curves. For the studied systems, the main reaction is concomitant with a number of side reactions which contribute to the global energy measured. From the calorimetric data measured, the formation constants for the species NiHEPES⁺, Tris⁺His⁻, TrisNiHis⁺ and [Ni(EDMA)₂OH]⁻ have been evaluated for the first time and the values obtained properly validated.     

Scaling law for the elastic response of spherical explosion-containment vessels

The substantial progress made in the development of portable, spherical explosion-containment vessels has led to its adoption for explosives-related transporting and manufacturing. A simple scaling law for engineering-design use has been obtained for the maximum first-cycle elastic-strain response to explosive loading by a centered, spherical charge of a representative high explosive known as Pentolite. Results from a computer program based on the work of Baker have been accurately fitted to a six-product power law that is a function of the density, elastic modulus, diameter, and thickness of the vessel and the weight of detonated explosive. Nonlinear and log-linear fits are compared and found to agree if the role of weighting factors is understood. An impulse approximation is used to indicate that the scaling-law parameters are reasonable.     

Chemical markup, XML, and the world wide web. 6. CMLReact, an XML vocabulary for chemical reactions

A set of components (CMLReact) for managing chemical and biochemical reactions has been added to CML. These can be combined to support most of the strategies for the formal representation of reactions. The elements, attributes, and types are formally defined as XMLSchema components, and their semantics are developed. New syntax and semantics in CML are reported and illustrated with 10 examples.     

Bromoiodinanes with an I(III)-Br bond: preparation, X-ray crystallography and reactivity as electrophilic brominating agents

Bromoiodinanes--conveniently and directly prepared from iodobenzenecarbinols and N-bromosuccinimide, and characterised for the first time crystallographically--act as electrophilic bromine donors.     

On the Asymptotic Depth of Multigraded Modules

The aim of this article is to establish, among other results, the asymptotic stability of the depth of the graded pieces of a nonstandard multigraded module. As a corollary, we get the asymptotic stability of the depth of the graded pieces of the multigraded Rees algebra defined by a finite set of ideals and their associated multigraded rings.     

Bilattices for deductions in multi-valued logic

In this exploratory paper we propose a framework for the deduction apparatus of multi-valued logics based on the idea that a deduction apparatus has to be a tool to manage information on truth values and not directly truth values of the formulas. This is obtained by embedding the algebraic structure V defined by the set of truth values into a bilattice B. The intended interpretation is that the elements of B are pieces of information on the elements of V. The resulting formalisms are particularized in the framework of fuzzy logic programming. Since we see fuzzy control as a chapter of multi-valued logic programming, this suggests a new and powerful approach to fuzzy control based on positive and negative conditions.     

Magnesium nitride as a convenient source of ammonia: preparation of primary amides

The use of magnesium nitride (Mg 3N 2) as a convenient source of ammonia has been explored for the direct transformation of esters to primary amides. Methyl, ethyl, isopropyl, and tert-butyl esters are converted to the corresponding carboxamides in good yields (75-99%).     

Synthesis of natural products from the Indian neem tree Azadirachta indica

The synthesis of five natural products (3, 6, 7, 10, and 14), isolated from the Indian neem tree Azadirachta indica, is reported from a common intermediate (2). The judicious choice of transacetalization conditions allows efficient access to both the azadirachtinin (9 and 10) and the azadirachtin (3, 6, 7, and 14) skeletons.     

Racemization-free synthesis of S-alkylated cysteines via thiol-ene reaction

Treatment of differently protected and unprotected cysteines with a variety of alkenes in the presence of a radical initiator (AIBN) afforded the corresponding S-alkylated cysteines in high yields and without racemization.