Investigation by solid-phase microextraction and gas chromatography/mass spectrometry of trail pheromones in ants

The Dufour's gland content of workers of two ant species of the genus Messor has been analyzed by solid-phase microextraction and gas chromatography with mass spectrometry (GC/MS). The structures of the compounds in the pheromonal mixtures have been determined. In both cases only one intact gland, inserted in a properly dimensioned capillary vial, is sufficient to produce a clean and fully interpretable GC/MS profile. It is worth noting that, for the first time in Messor ants, farnesol has been detected as a minor component of glandular secretion in Messor capitatus.     

Diversity Oriented Clicking (DOC): Divergent Synthesis of SuFExable Pharmacophores from 2‐Substituted‐Alkynyl‐1‐Sulfonyl Fluoride (SASF) Hubs

Diversity Oriented Clicking (DOC) is a unified click‐approach for the modular synthesis of lead‐like structures through application of the wide family of click transformations. DOC evolved from the concept of achieving “diversity with ease”, by combining classic C?C π‐bond click chemistry with recent developments in connective SuFEx‐technologies. We showcase 2‐S ubstituted‐A lkynyl‐1‐S ulfonyl F luorides (SASFs) as a new class of connective hub in concert with a diverse selection of click‐cycloaddition processes. Through the selective DOC of SASFs with a range of dipoles and cyclic dienes, we report a diverse click‐library of 173 unique functional molecules in minimal synthetic steps. The SuFExable library comprises 10 discrete heterocyclic core structures derived from 1,3‐ and 1,5‐dipoles; while reaction with cyclic dienes yields several three‐dimensional bicyclic Diels–Alder adducts. Growing the library to 278 discrete compounds through late‐stage modification was made possible through SuFEx click derivatization of the pendant sulfonyl fluoride group in 96 well‐plates—demonstrating the versatility of the DOC approach for the rapid synthesis of diverse functional structures. Screening for function against MRSA (USA300) revealed several lead hits with improved activity over methicillin.     

Optimal single‐embryo mass spectrometry fingerprinting

In pre‐implantation embryos, lipids play key roles in determining viability, cryopreservation and implantation properties, but often their analysis is analytically challenging because of the few picograms of analytes present in each of them. Matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) allows obtaining individual phospholipid profiles of these microscopic organisms. This technique is sensitive enough to enable analysis of individual intact embryos and monitoring the changes in membrane lipid composition in the early stages of development serving as screening method for studies of biology and biotechnologies of reproduction. This article introduces an improved, more comprehensive MALDI‐MS lipid fingerprinting approach that considerably increases the lipid information obtained from a single embryo. Using bovine embryos as a biological model, we have also tested optimal sample storage and handling conditions before the MALDI‐MS analysis. Improved information at the molecular level is provided by the use of a binary matrix that enables phosphatidylcholines, sphingomyelins, phosphatidylserines, phosphatidylinositols and phosphoethanolamines to be detected via MALDI(±)‐MS in both the positive and negative ion modes. An optimal MALDI‐MS protocol for lipidomic monitoring of a single intact embryo is therefore reported with potential applications in human and animal reproduction, cell development and stem cell research. Copyright © 2013 John Wiley & Sons, Ltd.     

Molecular Porous Photosystems Tailored for Long-Term Photocatalytic CO2 Reduction

The molecular-level structuration of two full photosystems into conjugated porous organic polymers is reported. The strategy of heterogenization gives rise to photosystems which are still fully active after 4 days of continuous illumination. Those materials catalyze the carbon dioxide photoreduction driven by visible light to produce up to three grams of formate per gram of catalyst. The covalent tethering of the two active sites into a single framework is shown to play a key role in the visible light activation of the catalyst. The unprecedented long-term efficiency arises from an optimal photoinduced electron transfer from the light harvesting moiety to the catalytic site as anticipated by quantum mechanical calculations and evidenced by in situ ultrafast time-resolved spectroscopy.     

Widely tunable 1.94-microm Tm:BaY2F8 laser

A novel BaY2F8 crystal doped with thulium ions is grown and extensively investigated. Owing to the large number of vibronic levels and to a favorable electron-phonon coupling, extremely wide absorption and emission bands around 1.9 microm are observed. A room-temperature Tm:BaY2F8 laser tunable over a 210-nm interval, from 1849 to 2059 nm, is demonstrated.     

Organocatalytic stereoselective epoxidation of trisubstituted acrylonitriles

The first diastereospecific and enantioselective epoxidation of trans-2-aroyl-3-arylacrylonitriles by means of the commercially available diaryl L-prolinol/tert-butyl hydroperoxide system has been developed. These diversely functionalized epoxides were obtained in excellent yield (up to 99%), complete diastereoselectivity for the trans-isomer, and good enantioselectivity (up to 84% ee). Highly enantioenriched epoxides can be easily obtained after a single crystallization (ee > 90%).     

Intracellular concentration map of magnesium in whole cells by combined use of X-ray fluorescence microscopy and atomic force microscopy

We report a novel experimental approach to derive quantitative concentration map of light elements in whole cells by combining two complementary nano-probe methods: X-ray fluorescence microscopy (XRFM) and atomic force microscopy (AFM). The concentration is derived by normalizing point-by-point the elemental (here Mg) spatial distribution obtained by XRFM, by the thickness measured using AFM. The considerable difference between the elemental distribution and the concentration maps indicates that this procedure is essential to obtain reliable information on the role and function of elements in whole cells.     

Effects of low-level laser therapy at wavelengths of 660 and 808 nm in experimental model of osteoarthritis

The aim of the present study was to analyze the influence of low-level laser radiation at wavelengths of 660 and 808 nm in an experimental model of osteoarthritis (OA). The sample was composed of 36 male adult Wistar rats divided into three groups (G1, G2 and G3). For the induction of cartilage injury, three injections of 4% papain and 10 μL of a cysteine solution were performed at right knee of the hind leg. Two weeks after the last injection, group G1 was treated with InGaAlP (660 nm, 100 mW, 3.57 W cm(-2), 40 s) and G2 was treated with AsGaAl (808 nm, 100 mW, 3.57 W cm(-2), 40 s) both with energy of 4 J. There were significant differences in the type of squamous epithelium between days 7 and 14 in G2 (P < 0.05) and on day 14 between G1 and G2 (P < 0.05). Moreover, statistically significant differences were found in the formation of new blood vessels between G1 and G3 on days 7 and 21 as well as between G2 and G3 on day 21. The formation of fibrotic tissue was greater in G3 (P < 0.05). In conclusion, laser therapy, especially at a wavelength of 808 nm, stimulated angiogenesis and reduced the formation of fibrosis in an experimental model of OA.     

A general phosphoric acid-catalyzed desymmetrization of meso-aziridines with silylated selenium nucleophiles

The first example of meso-aziridine desymmetrization with selenium nucleophiles is reported. The reaction, promoted by VAPOL-hydrogen phosphate using (phenylseleno)trimethylsilane as the nucleophile, proves to be very general and highly enantioselective (84-99% ee).