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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been recently described as an innovative and effective tool for identifying arthropods and mosquito blood meal sources. To test this approach in the context of an entomological survey in the field, mosquitoes were collected from five ecologically distinct areas of Mali. We successfully analysed the blood meals from 651 mosquito abdomens crushed on Whatman filter paper (WFPs) in the field using MALDI-TOF MS. The legs of 826 mosquitoes were then submitted for MALDI-TOF MS analysis in order to identify the different mosquito species. Eight mosquito species were identified, including Anopheles gambiae Giles, Anopheles coluzzii, Anopheles arabiensis, Culex quinquefasciatus, Culex neavei, Culex perexiguus, Aedes aegypti and Aedes fowleri in Mali. The field mosquitoes for which MALDI-TOF MS did not provide successful identification were not previously available in our database. These specimens were subsequently molecularly identified. The WFP blood meal sources found in this study were matched against human blood (n = 619), chicken blood (n = 9), cow blood (n = 9), donkey blood (n = 6), dog blood (n = 5) and sheep blood (n = 3). This study reinforces the fact that MALDI-TOF MS is a promising tool for entomological surveys.
Triatomines are haematophagous insects involved in the transmission of Trypanosoma cruzi, the aetiological agent of Chagas disease. The vector competence of these arthropods can be highly variable, depending on the species. A precise identification is therefore crucial for the epidemiological surveillance of T. cruzi and the determination of at-risk human populations. To circumvent the difficulties of morphological identification and the lack of comprehensiveness of the GenBank database, we hereby propose an alternative method for triatomine identification. The femurs of the median legs of triatomines from eight different species from French Guiana were subjected to matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis. Method evaluation was performed on fresh specimens and was applied to dry specimens collected between 1991 and 2003. Femur-derived protein extracts provided reproducible spectra within the same species along with significant interspecies heterogeneity. Validation of the study by blind test analysis provided 100% correct identification of the specimens in terms of the species, sex and developmental stage. MALDI-TOF mass spectrometry appears to be a powerful tool for triatomine identification, which is a major step forward in the fight against Chagas disease.
In recent years, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as an efficient tool for arthropod identification. Its application for field monitoring of adult mosquitoes was demonstrated, but identification of larvae has been limited to laboratory-reared specimens. Study aim was to test the success of MALDI-TOF MS in correctly identifying mosquito larvae collected in the field. Collections were performed at 13 breeding sites in urban areas of Marseille, a city in the South of France. A total of 559 larvae were collected. Of these, 73 were accurately morphologically identified, with confirmation either by molecular identification (n = 31) or analysis with MALDI-TOF MS (n = 31) and 11 were tested using both methods. The larvae identified belonged to six species including Culiseta longiareolata, Culex pipiens pipiens, Culex hortensis, Aedes albopictus, Ochlerotatus caspius and Anopheles maculipennis. A high intra-species reproducibility and inter-species specificity of whole larva MS spectra was obtained and was independent of breeding site. More than 92% of the remaining 486 larvae were identified in blind tests against the MS spectra database. Identification rates were lower for early and pupal stages, which is attributed to lower protein abundance and metamorphosis, respectively. The suitability of MALDI-TOF MS for mosquito larvae identification from the field has been confirmed.
To describe and analyze a large outbreak of Clostridium difficile 027 (CD-027) infections.
Confirmed CD-027 cases were defined as CD infection plus real-time polymerase chain reaction assay (PCR) positive for CD-027. Clinical and microbiological data on patients with CD-027 infection were collected from January 2013 to December 2015 in the Provence-Alpes-Côte-d’Azur region (southeastern France).
In total, 19 healthcare facilities reported 144 CD-027 infections (112 confirmed and 32 probable CD-027 infections) during a 22-month period outbreak. Although the incidence rate per 10,000 bed days was lower in long-term care facilities (LTCFs) than in acute care facilities (0.05 vs 0.14; P<.001), cases occurred mainly in LTCFs, one of which was the probable source of this outbreak. After centralization of CD testing, the rate of confirmed CD-027 cases from LTCFs or residential-care homes increased significantly (69% vs 92%; P<.001). Regarding confirmed CD-027 patients, the sex ratio and the median age were 0.53 and 84.2 years, respectively. The 30-day crude mortality rate was 31%. Most patients (96%) had received antibiotics within 3 months prior to the CD colitis diagnosis. During the study period, the rate of patients with CD-027 (compared with all patients tested in the point-of-care laboratories) decreased significantly (P=.03).
A large CD-027 outbreak occurred in southeastern France as a consequence of an initial cluster of cases in a single LTCF. Successful interventions included rapid isolation and testing of residents with potentially infectious diarrhea and cohorting of case patients in a specialized infectious diseases ward to optimize management.
The damage and ion distribution induced in Si by an inductively coupled plasma Xe focused ion beam was investigated by atom probe tomography. By using predefined patterns it was possible to prepare the atom probe tips with a sub 50 nm end radius in the ion beam microscope. The atom probe reconstruction shows good agreement with simulated implantation profiles and interplanar distances extracted from spatial distribution maps. The elemental profiles of O and C indicate co-implantation during the milling process. The presence of small disc-shaped Xe clusters are also found in the three-dimensional reconstruction. These are attributed to the presence of Xe nanocrystals or bubbles that open during the evaporation process. The expected accumulated dose points to a loss of >95% of the Xe during analysis, which escapes undetected.
In the current literature, the dispersion relation of parametrically forced surface waves is often identified with that of free unforced waves. We revisit here the theoretical description of Faraday waves, showing that forcing and dissipation play a significant role in the dispersion relation, rendering it bi-valued. We then determine the instability thresholds and the wavenumber selection in cases of both short and long waves. We show that the bifurcation can be either supercritical or subcritical, depending on the depth.
Reducing the spread of multidrug-resistant bacteria in hospitals remains a challenge. Current methods are screening of patients, isolation, and adherence to hygiene measures among healthcare workers (HCWs). More specific measures could rely on a better characterization of the contacts at risk of dissemination.
To quantify how close-proximity interactions (CPIs) affected Staphylococcus aureus dissemination.
Nested case-control study.
French long-term care facility in 2009.
Patients (n=329) and HCWs (n=261).
We recorded CPIs using electronic devices together with S. aureus nasal carriage during 4 months in all participants. Cases consisted of patients showing incident S. aureus colonization and were paired to 8 control patients who did not exhibit incident colonization at the same date. Conditional logistic regression was used to quantify associations between incidence and exposure to demographic, network, and carriage covariables.
The local structure of contacts informed on methicillin-resistant S. aureus (MRSA) carriage acquisition: CPIs with more HCWs were associated with incident MRSA colonization in patients (odds ratio [OR], 1.10 [95% CI, 1.04–1.17] for 1 more HCW), as well as longer CPI durations (1.03 [1.01–1.06] for a 1-hour increase). Joint analysis of carriage and contacts showed increased carriage acquisition in case of CPI with another colonized individual (OR, 1.55 [1.14–2.11] for 1 more HCW). Global network measurements did not capture associations between contacts and carriage.
Electronically recorded CPIs inform on the risk of MRSA carriage, warranting more study of in-hospital contact networks to design targeted intervention strategies.
Infect. Control Hosp. Epidemiol. 2015;36(8):922–929
In the context of the preservation of the cultural heritage, it is important to understand the alteration mechanisms of the materials constituting historical monuments and architecture. Limestone especially is widely used in many French monuments exposed to an urban aggressive atmosphere affecting their durability. To better understand the alteration mechanisms, the first step is to characterize at different scales the stone material properties. In one hand, the pore network that drives the fluids transfer inside the materials was characterized. And on the other hand, the alteration layer formed on several decades aged materials was studied. Results on this fine-scale characterization are discussed.
This paper presents power results of L-band packaged hybrid amplifiers using InAlN/GaN/SiC HEMT power dies. The high-power densities achieved both in pulsed and continuous wave (cw) modes confirm the interest of such technology for high-frequency, high-power, and high-temperature operation. We present here record RF power measurements for different versions of amplifiers. Up to 260 W, i.e. 3.6 W/mm, in pulsed (10 µs/10%) conditions, and 105 W, i.e. 2.9 W/mm, in cw conditions were achieved. Such results are made possible thanks to the impressive performances of InAlN/GaN transistors, even when operating at high temperatures. Unit cell transistors deliver output powers of 4.3 W/mm at Vds = 40 V in the cw mode of operation at the frequency of 2 GHz. The transistor process is described here, as well as the amplifiers design and measurements, with a particular focus to the thermal management aspects.
The development of the Neolithic way of life in the western Mediterranean during the sixth millennium cal. BC is the consequence of the spread of populations from the Near East after successive stages of cultural remodelling. Despite the clear contribution of the Near Eastern and Aegean Neolithic to the economic and technical changes that happened to the west, little is known here about their symbolic legacies, because of the scarcity of representations and ritual evidences associated to the earliest western Neolithic contexts. Excavations at the rock shelter of Pendimoun (southeastern France) yielded the first anthropomorphic stone sculpture from the western Mediterranean Neolithic (early sixth millennium cal. BC). Using both carving and painting techniques, it represents a realistic-looking human face and is a unique example within the western Mediterranean and European frameworks. After describing the shaping and colouring details of the mask, the authors here deal with its possible social significances and cultural connections.
A multiscale approach combining phase-contrast X-ray micro- and nanotomography is applied for imaging a Cretaceous fossil inflorescence in the resolution range from 0.75 μm to 50 nm. The wide range of scale views provides three-dimensional reconstructions from the external gross morphology of the inflorescence fragment to the finest exine sculptures of in situ pollen. This approach enables most of the characteristics usually observed under light microscopy, or with low magnification under scanning and transmission electron microscopy, to be obtained nondestructively. In contrast to previous tomography studies of fossil and extant flowers that used resolutions down to the micron range, we used voxels with a 50 nm side in local tomography scans. This high level of resolution enables systematic affinities of fossil flowers to be established without breaking or slicing specimens.
The Laschamp excursion is a period of reduced geomagnetic field intensity occurring 40.7 ± 1.0 kyr ago. As a consequence, cosmogenic isotope production increased dramatically and its sensitivity to solar activity was enhanced during this period. The latter occurs because a larger fraction of the lower-energy interstellar galactic cosmic-ray particles, normally excluded by the geomagnetic field, is able to reach Earth's atmosphere. This produces a cosmogenic isotope production signal with a significant structure. As high-resolution 10Be profiles from both Antarctica (EDC) and Greenland (NGRIP-GRIP) during this crucial period are now available, one can use them as input into a box carbon cycle model in order to predict atmospheric 14C variations due to the Laschamp excursion. For this purpose, 10Be data are converted into 14C, using production calculations for the 10Be-14C conversion, after correction for the estimated difference of sensitivity between polar and global 10Be deposition. Several scenarios of carbon cycle state are simulated, from preindustrial to glacial conditions. Applying two recent cosmogenic isotope production calculations for the 10Be to 14C conversion, we found that the resulting atmospheric Δ14C variations are very sensitive to which of these two are employed. For example, Δ14C amplitude under glacial conditions varies from 260‰ (EDC) and 320‰ (Greenland) to 430‰ (EDC) and 510‰ (Greenland) depending on the formulation used for 10Be-14C conversion.
Catherine Esnouf, Institut National de la Recherche Agronomique (INRA), Paris,Marie Russel, Institut National de la Recherche Agronomique (INRA), Paris,Nicolas Bricas, Centre de Co-opération Internationale en Recherche Agronomique pour le Développement (CIRAD), Paris
This chapter focuses on food systems using an innovative dual approach. First of all, by considering them in interaction with energy and chemical systems within ecosystems, it poses the question of resource allocation (land and biomass). Second, a socioeconomic approach then highlights the diversity of these food systems. Different types of systems co-exist and reflect different ways of producing, processing, distributing and consuming food products. The ‘global’ food system is a constantly changing combination of these different types of systems, all of which influence each other.
Thanks to this dual approach to food systems, new research questions have emerged. New analytical frameworks would enable a clearer understanding of the interconnections between food systems within ecosystems, on the one hand, and their diversity and constant recombination on the other.
Referring to the pioneering work of Malassis (1996), Rastoin et al. (2010) defined a food system (FS) as
an interdependent network of stakeholders (companies, financial institutions, public and private organisations) localised in a given geographical area (region, state, multinational region), participating directly or indirectly in the creation of a flow of goods and services geared towards satisfying the food needs of one or more groups of consumers, both locally and outside the area considered.
A lake-level record of Lake Ledro (northern Italy) spans the entire Holocene with a chronology derived from 51 radiocarbon dates. It is based on a specific sedimentological approach that combines data from five sediment profiles sampled in distinct locations in the littoral zone. On a millennial scale, the lake-level record shows two successive periods from 11,700 to 4500 cal yr BP and from 4500 cal yr BP to the present, characterized by lower and higher average lake levels, respectively. In addition to key seasonal and inter-hemispherical changes in insolation, the major hydrological change around 4500 cal yr BP may be related to a non-linear response of the climate system to orbitally-driven gradual decrease in insolation. The Ledro record questions the notion of an accentuated summer rain regime in the northern Mediterranean borderlands during the boreal insolation maximum. Moreover, the Ledro record highlights that the Holocene was punctuated by successive centennial-scale highstands. Correlations with the Preboreal oscillation and the 8.2 ka event, and comparison with the atmospheric 14C residual record, suggest that short-lived lake-level fluctuations developed at Ledro in response to (1) final steps of the deglaciation in the North Atlantic area and (2) variations in solar activity.
A novel topology for millimeter-wave-integrated transformers is proposed. The windings are stacked and secondaries are designed with different trace widths and different diameters from that of the primary, in order to obtain relatively high-inductance transformation ratios. Measurement and simulation results of 65 nm Complementary Metal Oxide Semiconductor (CMOS) and 130 nm combination of Bipolar and CMOS (BiCMOS) transformers present the impact of this structure on the inductances, quality factor, coupling coefficient, and minimum insertion loss. Within certain limits on the trace widths, it is shown that the proposed topology not only increases the transformation ratio but also improves its overall performance.
Osteoporosis is a disease characterized by a loss of bone density and an altered bone
architecture. These modifications lead to an increased risk factor for bone fracture,
particularly of the femoral neck. This disease can be explained by a disorder in the bone
remodeling process which is triggered by the apparition of micro-cracks within the bone.
According to Frost’s theory , these micro-cracks
appear for a specific local strain threshold. Thus, the knowledge of the microarchitecture
and quality of trabecular bone is essential to determine this local strain threshold. This
paper studied the mechanical trabecular bone behavior of 43 patients diagnosed as
osteoporotic whose femoral heads were replaced by hip prosthesis. From each patient, a
cylinder-shaped of trabecular bone samples was cored. Each sample was scanned by X-ray
micro-tomography before a compression test in order to reconstruct a reliable
Finite-Element (FE) model of the bone architecture in Abaqus. The force-displacement
curves were recorded for all the samples and calibrated by the experimental responses. The
force-displacement numerical curves were adjusted to the experimental ones, by modifying
the tissue microscopic mechanical behavior. This process leads to the determination of the
local strain threshold responsible for triggering the bone remodeling process.