Measurement of storage time, estimation of ion number and study of absorption line profile in a Paul trap

Europium (Eu⁺) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu⁺ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions. The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both experimentally and theoretically.     

Multivalent Inhibitors for Carbohydrate‐Processing Enzymes: Beyond the “Lock‐and‐Key” Concept

During the last decades, tremendous chemical efforts have been dedicated to design monovalent inhibitors of carbohydrate‐processing enzymes, with comparatively few rewards in terms of marketed drugs. Recently, an alternative to the traditional “lock and key” approach has emerged. Multivalency, a widely used strategy for lectin inhibition, has been successfully applied to specific glycosidases and glycosyltransferases.     

Simple but Precise Engineering of Functional Nanocapsules through Nanoprecipitation

A general, rapid, and undemanding method to generate at will functional oil‐filled nanocapsules through nanoprecipitation is reported. On the basis of polymer and hexadecane/water/acetone phase diagrams, the composition can be set so that polymer chains preferentially stick at the interface of the oil droplets to create nanocapsules. The nanocapsules can be decorated with biorelevant molecules (biotin, fluorescent tags, metal nanoparticles) within the shell and loaded with hydrophobic molecules in a simple one‐pot procedure.     

Hamilton's Principle and Rankine–Hugoniot Conditions for General Motions of Mixtures

In previous papers [1, 2], we presented hyperbolic governing equations and jump conditions for barotropic fluid mixtures. Now we extend our results to the most general case of twocomponent media. We obtain governing equations for each component. This is not a system of conservation laws. Nevertheless, using Hamilton's principle we are able to obtain a complete set of Rankine–Hugoniot conditions. For the twofluid case, the jump relations do not involve the conservation of the total momentum and the total energy.Sommario. In precedenti lavori [1, 2] sono state dedotte equazioni di governo iperboliche e condizioni di salto per miscele fluide barotropiche. I risultati sono estesi al caso più generale di mezzi a due componenti, ottenendo le equazioni di governo per ciascun componente. Questo sistema non è derivabile dalle leggi di conservazione. Nondimeno, usando il principio di Hamilton è possibile ottenere un insieme completo di condizioni di Rankine–Hugoniot. Nel caso dei due fluidi, le condizioni di salto non coinvolgono la conservazione del momento e dell'energia totali.     

Electrogenerated Chemiluminescence of Cationic Triangulene Dyes: Crucial Influence of the Core Heteroatoms

Trianguleniums are fascinating conjugated hexacyclic cations that exhibit interesting electronic and optical properties. Herein, the electrogenerated chemiluminescence (ECL) emission of this family of fluorescent dyes is reported for the first time. Redox behavior and fluorescence properties of eight cationic triangulene luminophores with different heteroatom patterns in the core structure and various pending substituents were examined to rationalize the ECL. Clearly, the more electron‐rich the carbocation, the more efficient the corresponding ECL; two very distinct classes of triangulenes can be drawn from these studies by using an ECL wall sufficiency formalism.     

Insights in the rational design of synthetic multivalent glycoconjugates as lectin ligands

Much effort has been made during the last decade to design lectin inhibitors as therapeutics against viral and bacterial adhesion or to control biological functions. The chemical strategy adopted generally consists in the tethering of several binding epitopes on a common scaffold. The resulting multivalent glycoconjugates often display a much higher binding affinity for their targets compared to their monovalent counterparts, a phenomenon designed as the "cluster" or "multivalent effect". Hundreds of multimeric architectures have been designed so far and some of the compounds displayed impressive gains in binding affinity or in vivo efficiency. Progress in this area is, however, hampered by the difficulty to predict the potency of the new multimeric inhibitors. This review presents the recent efforts to probe the important structural features of the synthetic multivalent glycoconjugates for a tight binding with specific lectins. We hope that the reported examples will aid the reader to design efficient multivalent ligands in a more predictable way.     

Correction: Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity

After the publication of the work entitled "Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity", by Kozlowski et al., BMC Biochemistry 2011, 12:29, we found that the legends to Figures 2 to 5 contain serious mistakes that compromise the comprehension of the work. This correction article contains the correct text of the legends to Figures 2 to 5.     

Rankine–Hugoniot conditions obtained by using the space–time Hamilton action

In the quadri–dimensional space–time, the variation of Hamilton’s action is a powerful tool to study the process equations for conservative fluid media. In this framework, Hamilton’s principle allows to obtain equation of motions, equation of energy but also Rankine–Hugoniot conditions. The variational method may be a versatile key to obtain the shock-wave conditions for complex media when the equations of processes are not expressed by linear or quasi-linear differential equations.

     

L'addition des organomagnesiens aliphatiques satures sur les triples liaisons disubstituees non conjuguees: IV. Influence d'un groupement fonctionnel thioether en α de la triple liaison. Action catalytique du cuivre

The addition reaction of ethylmagnesium bromide to the triple bond of the compounds of general formula EtSCH₂CCCH₂Y (where Y is the basic group OH, OR, NR₂, or SEt) is very weakly activated by the thioether group. Catalysis by magnesium impurities may be involved.With 1-ethylthio-4-dialkylamino-2-butynes (Y NR₂), (E) trisubstituted ethylenic compounds are selectively obtained. The reaction more readily occurs after the addition of cuprous chloride to the Grignard solution, and then its stereoselecitvity may be reversed.