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Abstract: Pesticides in foodstuff are becoming a major issue due to their intensive use in agriculture. Thus an appropriate control of their residues in food samples has to be operated. In this study we analysed 105 pesticides with GC/SQ-MS and 46 pesticides with HPLC/IT-MS after extraction with the QuECheRS method in four matrices (grape, lemon, onion and tomatoes). For GC-amenable substances, the LOD and LOQ ranged from 0.4 to 48.2μg/kg and from 1.2 to161μg/kg, respectively. For HPLC-amenable substances, they varied from 1.0 to 115μg/kg and from 3.3 to 382μg/kg, respectively. With GC/MS, 61–82% of the substances showed a recovery in the range of 70–110% and 6–30 % presented a recovery higher than 110% at the 500μg/kg fortification level. With HPLC/MS, 87–93% of the substances presented recoveries in the range of 70–110% at the 500μg/kg fortification level compared to 78–85% at the 50μg/kg fortification level. Lemon and onion showed poor recoveries but are known to be difficult matrices (high acidic and high sulfur content, respectively). The method was proved to be repeatable with RSD lower than 20% at 500μg/kg and lower than 15% at 50μg/kg with both devices. [Copyright &y& Elsevier]

Abstract: The influence of unfilled cavities at a liquid–solid interface on ultrasound propagation is investigated. This kind of interface exists only when the surface is rough and the liquid is non-wetting. Normally incident compression waves are used. Possible modelling approaches are discussed, showing that no model is able to efficiently describe this kind of interface. We demonstrate that wave transmission drops dramatically. It is suggested that the incoming ultrasonic energy induces the growth and the coalescence of the vapour phase contained in the unfilled cavities under ultrasound field. A major result of this paper is to provide proof that difficult experiments in metal–liquid can be replaced by easier experiments in water. [Copyright &y& Elsevier]

Abstract: With a view to analyse multiresidues of pesticides in soil samples, a new ultrasonic solvent extraction (USE) was compared to the European Norm DIN 12393 for foodstuff (extraction with acetone, partitioning with ethylacetate/cyclohexane and clean-up with gel permeation chromatography (GPC)), the QuECheRS method and a pressurised liquid extraction (PLE) method. Pesticides were analysed with both GC-MS and HPLC-MS/MS. The reference materials were the EUROSOIL 7 and its subsoil SO26 as well as a sea sand. All the substances were observed to be linear in the range of 4–800ngg−1 for the European Norm DIN 12393, 7–1400ngg−1 for the USE method and 20–4000ngg−1 for the QueCheRS and the PLE methods. Limits of detection (LOD) and limits of quantification (LOQ) were with HPLC between 0.006 and 0.23ngg−1 and between 0.022 and 0.77ngg−1, respectively, with the exception of diuron (LOD up to 11.8ngg−1; LOQ up to 39.2ngg−1). With GC they ranged from 3.0 to 87.5ngg−1 and from 10 to 292ngg−1, respectively. All substances could be recovered with USE as well as with the QuECheRS method; the European Norm DIN 12393 could not recover carbendazim and metamitron; the PLE carbendazim, metamitron and monolinuron. For the remaining substances, recoveries at a 500ngg−1 fortification level ranged from 10.9 to 96.3% with the USE. In comparison, the QuECheRS method was the most efficient extraction method with recoveries from 27.3 to 120.9%. It was followed by the European Norm DIN 12393 with recoveries between 6.8 and 108.1% and the PLE with recoveries from 12.2 to 153.2%. Recoveries were higher from the EUROSOIL 7 than from the SO 26. The repeatability expressed in term of standard deviation was below 20% for all substances and all materials. [Copyright &y& Elsevier]

Abstract: Bacground: Stenotrophomonas maltophilia (Smalto) is a prominent nosocomial pathogen, commonly isolated in the hospital environment. Multiple Smalto nosocomial outbreaks have been linked to contaminated water sources. This study aimed to develop a medium able to ease healthcare environment Smalto isolation. Methods: Financed, from March 2007 to June 2008, by a university hospital of Amiens’ clinical research program, this study allowed Stenotrophomonas maltophilia selective medium with coloured indicator (SM2i) development. SM2i is constituted of Mueller Hinton agar (MH), maltose, DL-methionine, bromothymol blue. The mixture sterilized is refreshed at 50°C, its pH adjusted to 7.1, and render selective by addition of vancomycin, imipenem and amphotericin B. Then, SM2i agar is sunk into 90cm diameter Petri dish dated and stored at 4°C for 4 weeks. SM2i is developed using Pasteur Institute culture type collection (CIP) strains of Smalto, Burkholderia cepacia, Pseudomonas aeruginosa (Psa) and a Smalto strain of our hygiene laboratory collection. It was validate on Psa imipenem-resistant and Enterococcus faecium vancomycin-resistant strains, then, tested on cold water first jet and faucet cotton-swabs samples. SM2i tests were made in comparison with the MH agar, MH agar plus four paper disks loaded 10μg of imipenem and Cetrimed agar. Its sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, accuracy, likehood-ratio (LR) and Youden index have been determined. Results: SM2i agar is better in culturing Smalto test-strains. On SM2i, Smalto colonies are smooth, round, greeny, olive or lime green, have a green olive centre with a peripheral lighter or a dark green centre with an olive green suburb surrounded by a blue halo. SM2i is a selective, specific, predictive, accurate medium to search for Smalto in healthcare environment. In 122 pairs of cold water first jet and taps cotton-swabs samples, Smalto was isolated from 14.8% of water samples, 10.7% of cotton-swabs samples. It was isolated alone in 6.6% of water samples and 2.5% of swab samples. Thus, smalto has biocontaminated 17.2% of cold water taps. Compared to MH agar, SM2i sensitivity, specificity, PPV, NPV, accuracy, LR were 100, 100, 100, 100, 100% and ∞, and 87.5, 100, 100, 98.1, 98.4% and ∞ for water and cotton-swabs samples respectively. Conclusion: SM2i is a selective, specific, predictive medium which can allow easily isolating and identifying accurately Smalto in environmental samples. Its evaluation on clinical samples is on going. [Copyright &y& Elsevier]

L'objectif de cette étude était d'analyser l'amplitude des mouvements translationnels et rotationnels survenant lors d'une séance de radiothérapie stéréotaxique osseuse. La pertinence des imageries pendant les fractions ainsi que l'influence du temps de traitement ont été évaluées. Dix patients installés en décubitus dorsal sur un matelas sous vide d'air bras relevés, les genoux posés sur une cale Kneefix™ ont été traités par trois arcs modulés de photons de 6 MV. La dose totale prescrite a été de 35 Gy (5 × 7 Gy). Afin de garantir un positionnement optimal du patient, une tomographie conique avant le traitement et une entre chacun des trois arcs ont été acquises. Les recalages entre les tomographies coniques et la scanographie de planification ont permis de déterminer en entre les fractions comme pendant les fractions la variabilité de positionnement du patient et de la corriger au moyen d'une table de traitement 6D. Les valeurs absolues des décalages translationnels (vertical, longitudinal, latéral) et rotationnels (tangage, lacet, roulis) obtenues pour les 180 tomographies coniques réalisées ont été relevées à partir du logiciel Offline Review (Varian medical system®). Le vecteur tridimensionnel translationnel et l'angle maximal des trois rotations ont été calculés. Les résultats sont présentés dans le Tableau 1. Les décalages issus de la tomographie conique avant le traitement ont permis d'évaluer le niveau de précision entre les fractions. Pour un intervalle de confiance à 95 % (IC95 %, valeur moyenne), nous avons obtenu une précision globale de 1,96 cm (0,78 cm) pour le vecteur tridimensionnel et 2,70° (1,46°) pour l'angle maximal de rotation. Les décalages obtenus sur les tomographies coniques entre chacun des trois arcs sont le reflet du niveau de précision pendant les fractions. Les résultats montrent une réduction notable des valeurs de décalages translationnels et rotationnels. Sur le plan statistique, ces résultats se traduisent par un vecteur tridimensionnel de 0,57 cm (0,21 cm) et un angle maximal de 1,41° (0,49°) pour un IC95 % sur la tomographie conique entre les arcs 1 et 2. Le même constat peut être fait pour celle entre les arcs 2 et 3, pour laquelle une précision à 95 % des cas nécessite un vecteur tridimensionnel de 0,42 cm (0,14 cm) et un angle maximal de 1,09° (0,33°). En corrélant les valeurs des décalages avec la durée de la séance de traitement, une tendance linéaire croissante a été mise en évidence : – vecteur tridimensionnel contre temps : pente 0,041 (IC 95 % : 0,026-0,056 ; p < 0,05) ; – angle maximal contre temps : pente 0,078 (IC95 % : 0,038-0,118 ; p = 0,049). Cette étude a permis de définir le seuil d'incertitude lié à notre technique de radiothérapie stéréotaxique osseuse et d'ajuster la marge de construction des volumes cible prévisionnels. L'association d'une imagerie pendant les fractions à un repositionnement 6D du patient parait inévitable à moins d'augmenter conséquemment les marges d'incertitudes de mouvement. La corrélation entre temps de traitement et corrections à appliquer incite à s'orienter vers des modalités permettant la réduction de la durée des séances. [ABSTRACT FROM AUTHOR]

Abstract: Background: Pseudomonas aeruginosa (Psa) and Stenotrophomonas maltophilia (Smalto) are major opportunistic waterborne pathogens causing hospital-acquired infections. This study aimed to assess the biocontamination level of cold water used in Amiens’ university hospital wards, from March to June 2008. Methods: We cultivated 122 pairs of cold water first jet and taps cotton-swabs on Cetrimide agar for Psa, on Stenotrophomonas maltophilia selective medium with coloured indicator (SM2i) for Smalto, on Mueller Hinton agar used as isolation medium reference for both, 48h at 30°C. Data analysed with Épi-Info 6.04dFr were compared with chi2 test, significant at p <.05. Results: Psa and Smalto were isolated in 26.2 and 14.8% of water samples and in 21.3 and 10.7% of swab samples respectively. They were associated in 11.5% of water samples and 5% of swab samples. Psa was alone in 13.1% of water samples and 7.4% of swab samples whereas Smalto was found in 6.6% of water and 2.5% of swabs. Psa and Smalto were isolated from 14.8% of water samples and 8.2% of swab samples of the same tap. Finally, respectively 35.2 and 17.2% of the cold water taps were biocontaminated by Psa and Smalto. In fact, microbiologic water taps contamination risk was two-fold higher for Psa than for Smalto, p <.001, without variation between wards. Conclusion: Sm2i and Cetrimide are suited and efficient medium respectively for Smalto and Psa isolation. Cold-water samples are sufficient for waterborne pathogens biocontamination risk appraisal. Our results urged healthcare workers on efficient water fittings microbiologic risk control to prevent healthcare associated waterborne infections, notably due to Psa and Smalto. [Copyright &y& Elsevier]