Usefulness of a quantitative real-time PCR assay using serum samples to discriminate between inactive, serologically positive and active human brucellosis

AbstractDiagnosis of brucellosis can be difficult in certain scenarios where conventional microbiological techniques have important limitations. The aim of this study was to develop a LightCycler Quantitative PCR assay in serum samples to discriminate between active and past brucellosis. In total, 110 serum samples from 46 brucellosis patients and 64 controls, including persons who had recently been treated for brucellosis, asymptomatic persons exposed to brucellosis, and patients with febrile syndromes involving a differential diagnosis with brucellosis, were studied. Brucella spp.-specific sequences of the PCR primers and probe were selected from the gene encoding an immunogenic membrane protein of 31 kDa (BCSP31). The analytical sensitivity was 1 × 101 fg of Brucella DNA. The mean threshold cycles for brucellosis patients and controls were 31.8 ± 1.7 and 35.4 ± 1.1, respectively (p <0.001). The best cut-off for bacterial DNA load was 5 × 103 copies/mL. At this cut-off, the area under the receiver operating characteristic curves was 0.963 (95% CI 0.920–1.005), with a sensitivity of 93.5% and a specificity of 98.4%. Under the assay conditions, the LightCycler Quantitative PCR in serum samples seems to be highly reproducible, rapid, sensitive and specific. It is therefore a useful method for both the initial diagnosis and the differentiation between past and active brucellosis

Rapid diagnosis of human brucellosis by SYBR Green I-based real-time PCR assay and melting curve analysis in serum samples

SUMMARYThe aim of this study was to develop a LightCycler-based real-time PCR (LC-PCR) assay and to evaluate its diagnostic use for the detection of Brucella DNA in serum samples. Following amplification of a 223-bp gene sequence encoding an immunogenetic membrane protein (BCSP31) specific for the Brucella genus, melting curve and DNA sequencing analysis was performed to verify the specificity of the PCR products. The intra- and inter-assay variation coefficients were 1.3% and 6.4%, respectively, and the detection limit was 5 fg of Brucella DNA (one genome equivalent). After optimisation of the PCR assay conditions, a standard curve was obtained with a linear range (correlation coefficient = 0.99) over seven orders of magnitude from 107 to 10 fg of Brucella DNA. The LC-PCR assay was found to be 91.9% sensitive and 95.4% specific when tested with 65 negative control samples and 62 serum samples from 60 consecutive patients with active brucellosis. The assay is reproducible, easily standardised, minimises the risk of infection in laboratory workers, and has a total processing time of < 2 h. It could therefore form a promising and practical approach for the rapid diagnosis of human brucellosis

Charge occupancy of two interacting electrons on artificial molecules - exact results

We present exact solutions for two interacting electrons on an artificial atom and on an artificial molecule made by one and two (single level) quantum dots connected by ideal leads. Specifically, we calculate the accumulated charge on the dots as function of the gate voltage, for various strengths of the electron-electron interaction and of the hybridization between the dots and the (one-dimensional) leads. With increasing of the (negative) gate voltage, the accumulated charge in the two-electron ground state increases in gradual steps from 0 to 1 and then to 2. The value 0 represents an "insulating" state, where both electrons are bound to shallow states on the impurities. The value of 1 corresponds to a "metal", with one electron localized on the dots and the other extended on the leads. The value of 2 corresponds to another "insulator", with both electrons strongly localized. The width of the "metallic" regime diverges with strength of the electron-electron interaction for the single dot, but remains very narrow for the double dot. These results are contrasted with the simple Coulomb blockade picture.Comment: 12 pages, 7 figure

Thermographic measurement of canopy temperature is a useful tool for predicting water deficit effects on fruit weight in citrus trees

[EN] Alternative and more practical methods for plant water stress detection than stem water potential (ψs) and stomatal conductance (gs) are needed when regulated deficit irrigation (RDI) strategies are applied. The aim of this experiment was to compare sap flow and canopy temperature (Tc) measurements with more classical methods like ψs or gs to predict the effect of deficit irrigation on fresh fruit weight in citrus trees. The experiment was performed during the summer of 2011 in a “Clementina de Nules” orchard undergoing RDI. Sap flow was determined by means of the compensation heat pulse method in well-watered and RDI trees. Tc was measured continuously with infrared thermometers (IRTs) mounted over the canopies and also weekly with an infrared hand-operated thermographic camera taking frontal images of the sunlit side of tree crowns. Concurrently, ψs and gs were also measured on all trees. Results showed that the evolution of the relative transpiration obtained with the sap flow sensors was in agreement with the plant water stress experienced. The values of Tc obtained with the fixed IRTs, normalized by air temperature (Tc − Ta) were in general poorly related with ψs and gs. However, when Tc was obtained from thermal imaging, there was a good correlation with ψs in days of relatively high water stress (i.e. when ψs differences among treatments were >1.0 MPa). The average fruit weight at harvest was significantly correlated with all the stress indicators, and the best correlation was that of thermographic Tc followed by ψs and gs. Overall, results showed that in citrus trees Tc measurement obtained from thermal imaging is a good tool to predict the effect of water deficit on fresh fruit weight.The authors thank H. Hernandez and T. Yeves for their help with the field work. This experiment has been funded by the RIDECO-CONSOLIDER CSD2006-00067 and Telerieg Interreg IV Sudoe projects. C. Ballester was holder of a predoctoral fellowship FPI-INIA-CCAA. D.S. Intrigliolo acknowledges the financial support received from the Spanish Ministry of Economy and Competitiveness (MINECO) program "Ramon y Cajal".Ballester, C.; Castel, J.; Jiménez Bello, MÁ.; Castel Sánchez, JR.; Intrigliolo Molina, DS. (2013). Thermographic measurement of canopy temperature is a useful tool for predicting water deficit effects on fruit weight in citrus trees. Agricultural Water Management. 122:1-6. https://doi.org/10.1016/j.agwat.2013.02.005S1612

Validity of a self-reported diagnosis of depression among participants in a cohort study using the Structured Clinical Interview for DSM-IV (SCID-I).

Abstract Background: Depression assessment in population studies is usually based on depressive symptoms scales. However, the use of scales could lead to the choice of an arbitrary cut-off point depending on the sample characteristics and on the patient diagnosis. Thus, the use of a medical diagnosis of depression could be a more appropriate approach. Objective: To validate a self-reported physician diagnosis of depression using the Structured Clinical Interview for DSM-IV (SCID-I) as Gold Standard and to assess the factors associated to a valid self-reported diagnosis. Methods: The SUN Project is a cohort study based on university graduates followed-up through postal questionnaires. The response to the question included in the questionnaire: Have you ever been diagnosed of depression by a physician? was compared to that obtained through the SCID-I applied by a psychiatrist or a clinical psychologist. The percentages of confirmed depression and non-depression were assessed for the overall sample and according to several characteristics. Logistic regression models were fitted to ascertain the association between different factors and a correct classification regarding depression status. Results: The percentage of confirmed depression was 74.2%; 95% confidence interval (95% CI) =63.3-85.1. Out of 42 participants who did not report a depression diagnosis in the questionnaire, 34 were free of the disease (%confirmed non-depression=81.1%; 95% CI=69.1- 92.9). The probability of being a true positive was higher among ex- smokers and non-smokers and among those overweight or obese but the differences were not statistically significant. Conclusion: The validity of a self-reported diagnosis of depression in the SUN cohort is adequate. Thus, this question about depression diagnosis could be used in further investigations regarding this disease in this graduate cohort study

Compilation of parameterized seismogenic sources in Iberia for the SHARE European-scale seismic source model.

Abstract: SHARE (Seismic Hazard Harmonization in Europe) is an EC-funded project (FP7) that aims to evaluate European seismic hazards using an integrated, standardized approach. In the context of SHARE, we are compiling a fully-parameterized active fault database for Iberia and the nearby offshore region. The principal goal of this initiative is for fault sources in the Iberian region to be represented in SHARE and incorporated into the source model that will be used to produce seismic hazard maps at the European scale. The SHARE project relies heavily on input from many regional experts throughout the Euro-Mediterranean region. At the SHARE regional meeting for Iberia, the 2010 Working Group on Iberian Seismogenic Sources (WGISS) was established; these researchers are contributing to this large effort by providing their data to the Iberian regional integrators in a standardized format. The development of the SHARE Iberian active fault database is occurring in parallel with IBERFAULT, another ongoing effort to compile a database of active faults in the Iberian region. The SHARE Iberian active fault database synthesizes a wide range of geological and geophysical observations on active seismogenic sources, and incorporates existing compilations (e.g., Cabral, 1995; Silva et al., 2008), original data contributed directly from researchers, data compiled from the literature, parameters estimated using empirical and analytical relationships, and, where necessary, parameters derived using expert judgment. The Iberian seismogenic source model derived for SHARE will be the first regional-scale source model for Iberia that includes fault data and follows an internationally standardized approach (Basili et al., 2008; 2009). This model can be used in both seismic hazard and risk analyses and will be appropriate for use in Iberian- and European-scale assessments

Computational Mechanism of Methyl Levulinate Conversion to γ-Valerolactone on UiO-66 Metal Organic Frameworks

Metal-organic frameworks (MOFs) are gaining importance in the field of biomass conversion and valorization due to their porosity, well-defined active sites, and broad tunability. But for a proper catalyst design, we first need detailed insight of the system at the atomic level. Herein, we present the reaction mechanism of methyl levulinate to γ-valerolactone on Zr-based UiO-66 by means of periodic density functional theory (DFT). We demonstrate the role of Zr-based nodes in the catalytic transfer hydrogenation (CTH) and cyclization steps. From there, we perform a computational screening to reveal key catalyst modifications to improve the process, such as node doping and linker exchange. © 2022 American Chemical Society. All rights reserved

Climate Assessment of Hydrogen Combustion Aircraft: Towards a Green Aviation Sector

As climate change aggravates, the aviation sector strives to minimize its climate footprint. To this end, international organizations, such as ICAO and ACARE, are promoting mitigation measures including novel technologies, operations, and energy carriers to reduce aircraft emissions significantly. Hydrogen (H2) as an alternative fuel has the advantage of eliminating CO2 and soot emissions and the potential to reduce NOx emission substantially. Nevertheless, burning H2 emits more H2O and increases the contrail formation probability. Therefore, the actual climate impact of hydrogen aircraft is still uncertain. This paper intents to evaluate the climate impact of a hydrogen powered aircraft considering the effects of H2O, NOx , and contrails . To frame the contribution of each individual climate agent, the research compares a hydrogen and a kerosene aircraft with similar mission capabilities. To assess the climate impact, a modeling chain was developed including network selection, flight routes calculation, aircraft and propulsion performance, emissions prediction, and climate impact assessment. In total, 2.24 million flights covering 1128 city pairs were analyzed. The energy consumption of hydrogen aircraft is about 10% higher than that of the kerosene aircraft due to the larger wetted area for hydrogen storage. However, the average atmospheric temperature response caused by the hydrogen aircraft is 67% lower compared to the kerosene aircraft due to the absence of CO2, the lower radiative forcing of hydrogen contrails, and the reduction in NOx emissions when assuming advanced hydrogen combustion technology. It was also observed that climate impact from hydrogen aircraft is more sensitive to flights over the tropics than to flights over the poles