Rapid cooling of lipid in a prilling tower Theoretical considerations and consequences on the structure of the microspheres

Two lipid binders, glyceryl behenate and paraffin wax, were examined regarding their ability to be used in a prilling process. Prilling has the advantage to produce microgranules very reproducible in size and shape but involves ultrafast cooling of liquid droplets. The different steps to produce solid micropheres from the molten state were successfully modelled to predict crystallisation time as a function of the binder used. Bulk versus microgranules characterization by differential scanning calorimetry, X-ray diffraction and microscopies showed the peculiar suitability of the 50/50 mixture of the two lipid binders for prilling, in agreement with the theoretical approach.     

Adaptive finite elements with large aspect ratio for mass transport in electroosmosis and pressure‐driven microflows

A space–time adaptive method is presented for the numerical simulation of mass transport in electroosmotic and pressure‐driven microflows in two space dimensions. The method uses finite elements with large aspect ratio, which allows the electroosmotic flow and the mass transport to be solved accurately despite the presence of strong boundary layers. The unknowns are the external electric potential, the electrical double layer potential, the velocity field and the sample concentration. Continuous piecewise linear stabilized finite elements with large aspect ratio and the Crank–Nicolson scheme are used for the space and time discretization of the concentration equation. Numerical results are presented showing the efficiency of this approach, first in a straight channel, then in crossing and multiple T‐form configuration channels. Copyright © 2009 John Wiley & Sons, Ltd.     

The quality-management system in research implemented in the food and food process quality research laboratory of the French Food Safety Agency

The French Food Safety Agency is a public body incorporating 12 laboratories that perform research to support expertise and public decisions taken in the fields of sanitary safety of food, animal health, and veterinary drugs. On the request of the General Management of the Agency a quality-management system in research (QMSR) is being implemented in the Food and Food Process Quality Research Laboratory. The experimental QMSR is based on existing standards and documents, describing the provisions required for scientific and technical competence, quality management, and project management. Furthermore, this QMSR also incorporates specific notions of great importance for research activities such as the positive and negative non-conformities, the non-confirmation of hypotheses, and the principle of evaluation of a research activity by peers for both quality and scientific aspects.     

Corrigendum

Reactions of NaMn(CO)₃ with RuCl₂(PMe₃)₄, RuCl₂(dppm)₂ and RuCl₂(PPh₃)₃ lead either to an ionic species [Ru₂Cl₃(PMe₃)₆]+[Mn(CO)₅]^? or to metal—metal bonded RuMn compounds such as RuMn(μ-CO)₂(CO)₃(μ-dppm)₂ Cl, and, quite unexpectedly, to the μ-phosphido complex RuMn(μ-PPh₂)(CO)₆(PPh₃)₂ via a hydride intermediate.     

Mathematical analysis of a simplified Hookean dumbbells model arising from viscoelastic flows

A stochastic model corresponding to a simplified Hookean dumbbells viscoelastic fluid is considered, the convective terms being disregarded. Existence on a fixed time interval is proved provided the data are small enough, using the implicit function theorem and a maximum regularity property for a three fields Stokes problem.     

Solid-phase synthesis of "mixed" peptidomimetics using Fmoc-protected aza-beta3-amino acids and alpha-amino acids

[structure: see text] A solid-phase fluorenylmethyloxycarbonyl (Fmoc)-based synthesis strategy is described for "mixed" aza-beta3-peptides as well as a convenient general approach for their required building blocks, the aza-beta3-amino acid residues (aza-beta3-aa). These monomers allow the synthesis of relatively large quantities of pure mixed aza-beta3-peptides. The required Fmoc-substituted aza-beta3-amino acids are accessible by convenient synthesis, and a number of monomers including those containing side chains with functional groups have been synthesized. The method was applied toward the solid-phase synthesis of aza-beta3-peptide mimetics of a biologically active histone H4 sequence.     

Some remarks on local operators in quantum electrodynamics

We assume the existence of a conserved current which generates locally gauge transformations of first kind. We are working in a local quantum Field Theory, where the fields are defined on a vector space where indefinite metric is allowed. We show that the Maxwell equations are not consistent with the above assumptions and the vectors obtained by applying local charged operators on the vacuum cannot describe physical states. Moreover we show that, if charged fields have non-trivial expectation value on the physical states, the vector space must contain vectors with negative norm. We discuss the relation between the local formulation of QED and a formulation in terms of physical states. As an example we study the transition from Gupta-Bleuler free QED to the Coulomb-gauge formulation.     

Photochemical oxidative addition of B-H bonds at ruthenium and rhodium

Metal phosphine hydrides of type RuP(4)H(2) and RhP(3)H(3) react photochemically with HB(pin)(pin = pinacolate) to form metal boryl hydride complexes via 16-electron intermediates generated by H(2) loss; the second order rate constants for reaction of the intermediates with HB(pin) are even larger than those for reaction with Et(3)SiH.