48 research outputs found

    Qualitative aspects and validation of a screening method for pesticides in vegetables and fruits based on liquid chromatography coupled to full scan high resolution (Orbitrap) mass spectrometry

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    The analytical capabilities of liquid chromatography with single-stage high-resolution mass spectrometry have been investigated with emphasis on qualitative aspects related to selective detection during screening and to identification. The study involved 21 different vegetable and fruit commodities, a screening database of 556 pesticides for evaluation of false positives, and a test set of 130 pesticides spiked to the commodities at 0.01, 0.05, and 0.20 mg/kg for evaluation of false negatives. The final method involved a QuEChERS-based sample preparation (without dSPE clean up) and full scan acquisition using alternating scan events without/with fragmentation, at a resolving power of 50,000. Analyte detection was based on extraction of the exact mass (±5 ppm) of the major adduct ion at the database retention time ±30 s and the presence of a second diagnostic ion. Various options for the additional ion were investigated and compared (other adduct ions, M + 1 or M + 2 isotopes, fragments). The two-ion approach for selective detection of the pesticides in the full scan data was compared with two alternative approaches based on response thresholds. Using the two-ion approach, the number of false positives out of 11,676 pesticide/commodity combinations targeted was 36 (0.3 %). The percentage of false negatives, assessed for 2,730 pesticide/commodity combinations, was 13 %, 3 %, and 1 % at the 0.01-, 0.05-, and 0.20-mg/kg level, respectively (slightly higher with fully automated detection). Following the SANCO/12495/2011 protocol for validation of screening methods, the screening detection limit was determined for 130 pesticides and found to be 0.01, 0.05, and ≥0.20 mg/kg for 86, 30, and 14 pesticides, respectively. For the detected pesticides in the spiked samples, the ability for unambiguous identification according to EU criteria was evaluated. A proposal for adaption of the criteria was made

    The Establishment of Genetically Engineered Canola Populations in the U.S.

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    Concerns regarding the commercial release of genetically engineered (GE) crops include naturalization, introgression to sexually compatible relatives and the transfer of beneficial traits to native and weedy species through hybridization. To date there have been few documented reports of escape leading some researchers to question the environmental risks of biotech products. In this study we conducted a systematic roadside survey of canola (Brassica napus) populations growing outside of cultivation in North Dakota, USA, the dominant canola growing region in the U.S. We document the presence of two escaped, transgenic genotypes, as well as non-GE canola, and provide evidence of novel combinations of transgenic forms in the wild. Our results demonstrate that feral populations are large and widespread. Moreover, flowering times of escaped populations, as well as the fertile condition of the majority of collections suggest that these populations are established and persistent outside of cultivation

    Detecting faults and stratigraphy in limestone with Ground-Penetrating Radar: A case study in Rustrel

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    ACTInternational audienceSurface Ground-Penetrating Radar (GPR) data have been acquired along the floor as well as along the vertical walls of a tunnel inside a karstic limestone reservoir in Rustrel. Geological study previously demonstrated the existence of stratification planes with an average dip of 25° to the south and numerous subvertical fault planes. The mono-offset GPR profile analysis acquired along the vertical wall of the tunnel demonstrates the presence of dipping reflectors that can be followed as deep as 16 m from the acquisition surface with 250 MHz nominal antennas. The position of these reflectors coincides with observations of faults recorded in a report written during the tunnel excavations. © 2017 IEEE

    The utility of fetal fibronectin in asymptomatic singleton and twin pregnancies with a cervical length \u3c= 10 mm

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    OBJECTIVE: To examine the utility of fetal fibronectin (fFN) for predicting spontaneous preterm birth (PTB) in asymptomatic women with a cervical length (CL) <10 mm compared to those with a CL 11–25 mm. METHODS: Data was collected on all women with non-anomalous singleton and twin gestations who underwent transvaginal CL at a single institution between 2009 and 2012. Women with an incidental short cervix (CL ≤25 mm) between 22–32 weeks who had an fFN result within 7 days thereafter were included. Indicated preterm deliveries at <14 days of fFN, women who underwent cerclage placement, and terminations of pregnancy were excluded. The primary outcome was spontaneous PTB within 7 and 14 days of the fFN. Sensitivity, specificity, and positive (PPV) and negative predictive value (NPV) of fFN for a CL <10 mm was calculated for singletons and twins and compared to those with a CL 11–25 mm. RESULTS: Of the 213 women included, 117 (54.9%) were singletons and 96 (45%) were twins. Baseline characteristics were similar between those with a CL <10 mm and with a CL 11–25 mm in both singletons and twins. The NPV of fFN for delivery within 7 days in singletons and twins with a CL <10 mm was 100%, similar to those with a CL 11–25mm (93–100%). The NPV of fFN for delivery within 14 days in singletons and twins with a CL <10 mm remained high (87.5–100%) when compared to those with a CL 11–25mm (93–100%). The PPV of fFN for delivery within 7 and 14 days in both singletons and twins with a CL<10 mm was low (10–25%) and similar to those with a CL 11–25 mm (7.1–24.4%). CONCLUSIONS: The NPV of fFN in asymptomatic singleton and twin pregnancies with a CL <10 mm is high and comparable to the NPV of fFN in women with a longer CL. Routine fFN collection in this select population should be considered as it may avoid unnecessary and costly admissions, as well as assist with timing of antenatal corticosteroids

    Mapping of contaminant plumes with geoelectrical methods. A case study in urban context

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    International audienceDuring the past two decades, the diagnosis and monitoring of polluted sites have become more important. Urban sites are particularly difficult to study, because they are contaminated with various pollutants, and there is a large physical and chemical heterogeneity. The heterogeneity comes from the landfilling of various solid wastes and remolded soil (endogenous or exogenous) from which they were constituted over time. Traditional techniques such as wells monitoring, are often insufficient to evaluate the extension of soil contamination. This is why we proposed a geoelectrical methodology from the fastest to the most information rich technique, showing all carry out and acquisition times: electromagnetic low frequency conductivity mapping, electrical resistivity profiles, chargeability profiles and spectral induced polarization (SIP) soundings. This strategy has been successfully applied to an urban site located in the Paris Basin (France). A conductivity map in relation with geochemical and lithological informations should provide us information to implement electrical resistivity and chargeability profiles. The latter allowed us to differentiate 3 main anomaly zones that have been determined. As interpretation of chargeability profiles is difficult, because it integrates polarization mechanisms with different relaxation times, we add spectral induced polarization soundings that provide us information concerning the contaminant nature. We determined the extension of an organic phase, and of 2 highly mineralized zones that could be linked to biodegraded and/or with pyrite areas. That theory is consistent with groundwater analysis and SIP data. The conclusion is that the suggested methodology is well suited to the study of urban contaminated sites including several different pollutants

    Computer Science and Engineering Research Review 1976-1977

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    Table of Contents: Introduction / Robert L. Sproull p. 3; RIG, Rochester's Intelligent Gateway: System Overview / Eugene Ball, Richart Rashid p. 5; The CERF Computer System / Neil Wilhelm, Daved Pessell, Charles Merriam p. 12; Geometric Modelling of Mechanical Parts and Processes / Herbert Voelcker, Aristides Requicha p. 17; Automatic Data Structure Selection / Jerome Feldman, James Low, Paul Rovner p. 29; Seminar Meetings p. 34; Publications p. 37; Grant Support p. 3

    Apport des bases médico-administratives en épidémiologie et santé publique des maladies infectieuses

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    International audienceBackgroundThe public health burden resulting from infectious diseases requires efforts in surveillance and evaluation of health care. The use of administrative health databases (AHD) and in particular the French national health insurance database (SNIIRAM) is an opportunity to improve knowledge in this field. The SNIIRAM data network (REDSIAM) workshop dedicated to infectious diseases conducted a narrative literature review of studies using French AHD. From the results, benefits and limits of these new tools in the field of infectious diseases are presented.MethodsPublications identified by the members of the workgroup were collected using an analytical framework that documented the pathology of interest, the aim of the study, the goal of the developed algorithm, the kind of data, the study period, and the presence of an evaluation or a discussion of the performance of the performed algorithm.ResultsFifty-five articles were identified. A majority focused on the field of vaccination coverage and joint infections. Excluding vaccine coverage field, the aim of 28 studies was epidemiological surveillance. Twenty-six studies used hospital databases exclusively, 18 used ambulatory databases exclusively and 4 used both. Validation or discussion of the performed algorithm was present in 18 studies.ConclusionsThe literature review confirmed the interest of the French AHD in the infectious diseases field. The AHD are additional tools of the existing surveillance systems and their use will probably be more frequent in the coming years given their advantage and reliability. However, incoming users need to be assisted. Thus, the workgroup will contribute to a reasonable use of AHD and support future developments.Position du problèmeCompte tenu des enjeux liés à leur poids en santé publique, les maladies infectieuses nécessitent des efforts de surveillance et d’évaluation de leur prise en charge. L’utilisation des bases de données médico-administratives (BDMA) et notamment du Système national d’information inter-régimes de l’Assurance maladie (Sniiram) constitue une opportunité d’améliorer les connaissances dans ce domaine. Le groupe de travail du Réseau données Sniiram (REDSIAM) dédié aux maladies infectieuses (GT infectieux) a réalisé une revue narrative de la littérature des travaux se basant sur des BDMA française, et montre l’intérêt et les limites de ces nouveaux outils dans le champ des maladies infectieuses.MéthodesLes publications renseignées par les membres du GT infectieux ont été colligées en utilisant une grille d’analyse documentant la pathologie étudiée, l’objectif de l’étude, l’utilisation d’un algorithme, le type de données utilisées, la période d’étude et la présence d’une évaluation ou discussion de la performance des algorithmes.RésultatsAu total, 55 publications ont été identifiées. La couverture vaccinale et les infections ostéoarticulaires étaient les sujets les plus étudiés. Hors champ vaccinal, 28 études avaient pour objectif la surveillance épidémiologique d’une pathologie infectieuse ; 26 études ont utilisé exclusivement les bases de données hospitalières, 18 uniquement les bases de données de soins ambulatoires et 4 les deux types de bases de données. Pour 18 études, les performances de l’algorithme ont été validées ou discutées.ConclusionLa synthèse menée par le GT infectieux a permis de confirmer l’intérêt des BDMA françaises dans l’étude des maladies infectieuses. Les BDMA constituent un outil complémentaire des systèmes existants dans le domaine des maladies infectieuses et leur utilisation devrait être croissante dans les prochaines années compte tenu de leur avantage et de leur fiabilité. Un travail sera néanmoins nécessaire pour accompagner les utilisateurs. Le GT infectieux aura alors toute sa place pour contribuer à une utilisation raisonnée des BDMA et accompagner les évolutions à venir
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