Analysis of β-agonists by HPLC/ESI-MS(n) in horse doping control

A sensitive method using LC/ESI-MS(n) has been developed on a quadrupole linear ion trap mass analyser for the detection of nine β(2) agonists (cimaterol, clenbuterol, fenoterol, formoterol, mabuterol, terbutaline, ractopamine, salbutamol and salmeterol) in horse urine. The method consists of solid-phase extraction on CSDAU cartridges before analysis by LC/ESI-MS(n) . The efficiency of extraction combined with the sensitivity and the selectivity of MS(n) allowed the detection of these compounds at pg/mL levels. Administration studies of fenoterol and formoterol are reported and show their possible detection after inhalation. The method is applicable for screening and confirmatory analysis.     

Synthesis and clathrates of oligomeric 2-O-naphthoide macrocycles

New macrocyclic O-naphthoides 4-6 were synthesized from dehydration reactions of 3-hydroxy- and 7-tert-butyl-3-hydroxy-2-naphthoic acids, respectively. Their X-ray structures were determined and their clathrate inclusion properties were investigated. Hexamer 6 formed an inclusion clathrate with four chloroform molecules. The trimer 5, by analogy with tri-o-thymotide, was studied for its potential optical resolution effects.     

Synthesis of Fluorinated Graphene Oxide and its Amphiphobic Properties

The richly functionalized basal plane bonded to polar organic moieties makes graphene oxide (GO) innately hydrophilic. Here, a methodology to synthesize fluorinated graphene oxide by oxidizing the basal plane of fluorinated graphite, allowing for tunable hydrophobicity of GO, is reported. Fluorine exists as tertiary alkyl fluorides covalently bonded to graphitic carbons, and using magic‐angle spinning (MAS) ¹³C NMR as a primary tool chemical structures for the two types of synthesized fluorinated graphene oxides (FGOs) with significantly different fluorine contents are proposed. The low surface energy of the C–F bond drastically affects GO's wetting behavior, leading to amphiphobicity in its highly fluorinated form. Ease of solution processing enables the fabrication of inks that are spray‐painted on various porous/non‐porous substrates. These coatings maintain amphiphobicity for solvents with surface tensions down to 59 dyn/cm, thus bypassing existing lithographic means to create similar surfaces. The approach towards fluorinating GO and fabricating graphene‐based surfaces with tunable wettability opens the path towards unique, accessible, carbon‐based amphiphobic coatings.     

Decay of 129Ce to low-lying positive-parity states in 129La

Low-lying levels of the ¹²⁹La isotope have been investigated through the β⁺/EC decay of ¹²⁹Ce. The radioactive nuclei were produced in the ⁹⁴Mo+⁴⁰Ca reaction at a bombarding energy of 255 MeV and transported with a He-jet system. On-line mass separation was used to select the ¹²⁹Ce beta-decay γ-γ-t, X- γ- t, e^?-γ -t coincidence measurements as well as time multi-analysis were performed. Internal conversion electrons were recorded with a magnetic selector and multipolarities deduced. The level scheme of ¹²⁹La is discussed and compared with the calculations made in the frame of the neutron-proton Interacting Boson-Fermion Model (IBFM-2).     

Decay of127Ce to low-lying states in127La

The high-spin states of¹⁹⁸Bi have been studied in the reaction¹⁸⁷Re(¹⁶O, 5n)¹⁹⁸Bi at¹⁶O energies from 85 to 105 MeV. In-beam measurements of γ-ray excitation functions, γ-γ-t coincidences and γ-ray angular distributions were carried out with six BGO(AC)HPGe detectors and one intrinsic Ge planar detector. A level scheme for¹⁹⁸Bi- with 26 γ rays was established for the first time, including a 15⁺ isomer with a measured half-life of 8.0±3.6 ns.     

Transient entanglements and clusters in dilute polymer solutions

A convenient method to monitor polymer dissolution is to measure the pressure drop created by passing a polymer solution through a capillary constriction rheometer. In this work, we studied the dissolution of polyethylene oxide (PEO) and cationic starch (C‐starch). We found that for freshly dissolved and entangled PEO, the main contribution to the overall pressure drop is due to the contraction and expansion of PEO entanglements at the entrance and exit of the capillary, and that the friction in the capillary plays a minor role. On the other hand, for well‐dissolved PEO, because of the absence of PEO entanglements, the loss of pressure is mainly due to friction. At high velocities the contraction and expansion coefficient for freshly dissolved PEO was more than 20 times higher than for well‐dissolved PEO, resulting in a three times higher overall pressure drop. C‐starch consists of amylopectin (～ 85%) and amylose and is known to contain clusters when freshly dissolved, likely formed from the globular amylopectin molecules. For C‐starch, the main contribution to the overall pressure drop is due to friction. Entrance and exit effects contribute only 10% to the overall pressure drop, which might be due to the linear amylose molecules in C‐starch. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 253–262, 2008     

Synthese et isomerisation de methoxycarbonyl-5 dihydropyrannones-2

Condensation of dimethyl 3-methylglutaconate with ketones provides a one pot route for the preparation of 5-methoxycarbonyl-4-methyldihydropyran-2-ones. The experimental conditions to give selectively pyran-2-ones isomers are discussed. The structure of the different products was established on the basis of ¹H and ¹³C nmr spectral data.