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.     

Electrophilic lactonization as a tool in acyclic stereocontrol. Synthesis of serricornin

Several electrophilic lactonization procedures have been explored as a means of functionalizing olefinic carboxylic acids with relative asymmetric induction, Iodolactonization of δ,? -unsaturated acids under conditions of thermodynamic control exhibits good 1,2- and 1,3-, but not 1,4-induction in the formation of δ-lactones. Mercurilactonization proceeds with good stereocontrol in the formation of both γ- and δ-lactones (1,2-induction), but suffers from the difficulty of elimination during reductive demercuration; phenylselenolactonization with N-(phenylseleno)phthalimide is apparently kinetically controlled, affording high induction with 10, a strongly sterically biased substrate leading to a δ-lactone, but not with 16, which leads to a γ-lactone. In contrast, hydroxymethyllactonization proceeds with good stereocontrol in the case of 26, the ester of 10, but not with the analogous ester of 16. The lactones resulting from cyclization of 10 and 13 were converted in stereospecific fashion into each of the stereoisomers of(±)-serricornin.     

Incongruent restricted disjoint covering systems

We define an incongruent restricted disjoint covering system on [1,n] as a set of congruence classes such that each integer in the interval [1,n] belongs to exactly one class, and each class contains at least two members of the interval. In this paper we report some computational and structural results and present some open problems concerning such systems.     

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.     

Acceptable and predominant correlated equilibria

For stategic-form games with communication, acceptable correlated equilibria are defined as correlated equilibria that are stable when every player has an infinitesimal probability of trembling to any of his feasible actions. A set of acceptable actions is defined for each player, and it is shown that a correlated equilibrium is acceptable if and only if all unacceptable actions have zero probability. The unacceptable actions can be found by computing certain vectors called codomination systems, which extend the concept of dominated actions. Predominant correlated equilibria are defined by iterative elimination of unacceptable actions and are shown to exist.     

Sec-butyl (Z)-7-tetradecenoate. A novel sex pheromone component from the western grapeleaf skeletonizer, harrsina brillians.

The first reported instance of an unsaturated $\text{sec}$-butyl ester as a lepidopteran sex pheromone is described including its identification and synthesis.