Increase of malaria attacks among children presenting concomitant infection by Schistosoma mansoni in Senegal

Helminthic infections concomitant with malaria are common in inter-tropical areas. A recent study showed that mice co-infected with Schistosoma mansoni and Plasmodium chabaudi develop higher P. chabaudi parasitaemia and had a higher mortality rate. This important observation deserved to be further investigated among human populations. Malaria attacks were recorded in 512 children aged 6–15 years living in Richard Toll (Northern Senegal) among whom 336 were infected by S. mansoni, and 175 were not. The incidence rate of malaria attacks was significantly higher among S. mansoni-infected individuals, particularly those carrying the highest worm loads, as compared to uninfected subjects (26.6% versus 16,4 %). In contrast, the rate of malaria attacks was lower, without reaching significance, in medium grade S. mansoni infections. Thus, infection by S. mansoni affects susceptibility to malaria, but this can vary according to the intensity of parasite load. The immunological mechanisms underlying this dual effect need to be further explored

A Decade of Antifungal Leads from Natural Products:2010-2019

In this review, we discuss novel natural products discovered within the last decade that are reported to have antifungal activity against pathogenic species. Nearly a hundred natural products were identified that originate from bacteria, algae, fungi, sponges, and plants. Fungi were the most prolific source of antifungal compounds discovered during the period of review. The structural diversity of these antifungal leads encompasses all the major classes of natural products including polyketides, shikimate metabolites, terpenoids, alkaloids, and peptides

Wind-tunnel tests of a heavy-class helicopter optimised for drag reduction

Wind-tunnel tests of a heavy-class helicopter model were carried out to evaluate the effectiveness of several components optimised for drag reduction by computational fluid dynamics analysis. The optimised components included different hub-cap configurations, a fairing for blade attachments and the sponsons. Moreover, the effects of vortex generators positioned on the back ramp were investigated. The optimisation effect was evaluated by comparison of the drag measurements carried out for both the original and the optimised helicopter configurations. The comprehensive experimental campaign involved the use of different measurement techniques. Indeed, pressure measurements and stereo particle image velocimetry surveys were performed to achieve a physical insight about the results of load measurements. The test activity confirms the achievement of an overall reduction of about 6% of the original model drag at cruise attitude

Comparación de dos pruebas de aglutinación (Toxolatex ® y Toxoscreen ®) en el diagnóstico de la toxoplasmosis: propuesta de inclusión en un programa de control

This study evaluated a latex agglutination test (Toxolatex ®, Fumouze) and a direct agglutination test using a whole antigen (Toxoscreen ®, Biomerieux) for the screening of toxoplasmosis antibodies, by means of comparison with the dye test (Sabin Feldman) (DT) and a fluorescent antibody test (IFAT). On 500 sera, a good correlation was obtained for these methods with DT (TI 96.8% and TS 98.6%) and IFAT (TL 95.4% and TS 97.2%). In addition to detecting antitoxoplasma immunoglobulin M antibodies. TL is a rauid, easy and inexpensive technique. Based these findings, we recommend the agglutination testior initial screening of specific antibodies against toxoplasmosis in seroepidemiological surveys and pregnancy control program.Este estudio evaluó las pruebas de aglutinación en Iátex. Toxolatex ®. Furnouze (.T L). .v aglutinación directa. Toxoscreen ®, Biomerieux (TS), mediante la comparación con las pruebas de referencia: prueba de neutralización, dye test (DT) e inmunofluorescencia indirecta (IFI). En los 500 sueros estudiados, se encontró una buena concordancia entre las técnicas estudiadas y las de referencia asi: DT (TI, 963% y TS. 98.6%) e IFI (TI 95,4% y TS 97.2%) El TL, además de detectar anticuerpos de clase IgM antitoxoplasma, es una técnica poco costosa y de fácil y rápida realización. Los resultados de este estudio permiten recomendar las pruebas de aglutinación para el tamizaje de anticuerpos especificas antitoxoplasma en los programas de control prenatal y en los estudios seroepidemiológicos

Fish under influence: a macroecological analysis of relations between fish species richness and environmental gradients among European tidal estuaries

Estuarine fish assemblages are subject to a great environmental variability that largely depends on both upstream fluvial and downstream marine influences. From this ecohydrological view, our study introduces a macroecological approach aiming to identify the main environmental factors that structure fish assemblages among European tidal estuaries. The present paper focuses on the influence of large scale environmental gradients on estuarine fish species richness. The environment of 135 North-eastern Atlantic estuaries from Portugal to Scotland was characterized by various descriptors especially related to hydromorphology. Major environmental trends among estuaries were underlined using multivariate techniques and cluster analyses applied to abiotic data. In particular, an integrative system size covariate was derived from a principal component analysis. Factors explaining patterns of species richness at different scales from local habitat to regional features were highlighted. Based on generalised linear models, the estuarine system size, and more particularly the entrance width, and also the continental shelf width were identified as the best explanatory variables of estuarine fish species richness at a large scale. Our approach provides a standardized method to estimate the relationship between fish assemblages and environmental factors. This constitutes a first step in assessing estuarine ecological status and studying the effects of additional factors such as anthropogenic disturbances

Integrated geophysical-petrological modeling of lithosphere-asthenosphere boundary in central Tibet using electromagnetic and seismic data

We undertake a petrologically driven approach to jointly model magnetotelluric (MT) and seismic surface wave dispersion (SW) data from central Tibet, constrained by topographic height. The approach derives realistic temperature and pressure distributions within the upper mantle and characterizes mineral assemblages of given bulk chemical compositions as well as water content. This allows us to define a bulk geophysical model of the upper mantle based on laboratory and xenolith data for the most relevant mantle mineral assemblages and to derive corresponding predicted geophysical observables. One-dimensional deep resistivity models were derived for two groups of MT stations. One group, located in the Lhasa Terrane, shows the existence of an electrically conductive upper mantle layer and shallower conductive upper mantle layer for the other group, located in the Qiangtang Terrane. The subsequent one-dimensional integrated petrological-geophysical modeling suggests a lithosphere-asthenosphere boundary (LAB) at a depth of 80¿120 km with a dry lithosphere for the Qiangtang Terrane. In contrast, for the Lhasa Terrane the LAB is located at about 180 km but the presence of a small amount of water in the lithospheric mantle (<0.02 wt%) is required to fit the longest period MT responses. Our results suggest two different lithospheric configurations beneath the southern and central Tibetan Plateau. The model for the Lhasa Terrane implies underthrusting of a moderately wet Indian plate. The model for the Qiangtang Terrane shows relatively thick and conductive crust and implies thin and dry Tibetan lithosphere.Peer Reviewe

Radiofrequency map of an NMR coil by imaging

We propose a new imaging method to obtain a map of the radiofrequency (RF) field amplitude over a sample. The sequence contains three RF pulses (alpha, 2 alpha, and alpha) and produces two images by a classical spin echo and a stimulated echo. A third image is computed and gives the distribution of the flip angle alpha, and so the RF amplitude, over the sample. The accuracy of the flip angle determination is verified on an homogeneous sample and results show a good correlation between experimental and theoretical flip angles in the range of 50 degrees to 130 degrees. Experiments with a surface coil and a resonator show the method is available in an inhomogeneous RF field. Images obtained on the calf of a volunteer confirms the independence of the computed RF distribution from proton density, T1, or T2 contrast

Acquisition of spin echo and stimulated echo by a single sequence: application to MRI of diffusion

A new method is described to measure the restricted diffusion coefficient with magnetic resonance imaging. The two images necessary to calculate the diffusion image are obtained with a simultaneous acquisition of a spin-echo and a stimulated echo, and so, in half the time needed by usual spin-echo or stimulated echo method. A different diffusion contrast is created on each echo. A map of an estimate of the diffusion coefficient and an estimation of T1 value are obtained with only one experiment. The accuracy of the method has been evaluated on phantom and results are in agreement with values found in previous papers and with measurements performed with a usual spin-echo method. Furthermore, in vivo measurements have shown that this method can be used without electrocardiogram triggering

T1 mapping from spin echo and stimulated echoes

We present an imaging method to obtain a map of the spin-lattice relaxation time. Images were acquired with the same spatial resolution and in the same time as for a regular spin-echo acquisition. The sequence was based on the simultaneous acquisition of a spin echo and several stimulated echoes with the same intensity except for T1 weighting which increases with the interval between the excitation pulse and the readout pulse. T1 values obtained on phantoms were compared to those from the inversion-recovery method and show the accuracy (2%) and the precision (5%) of the method. T1 images of the brain of a healthy volunteer are presented and demonstrate the ability of the method to obtain T1 mapping in vivo in 12 min and without susceptibility artifacts. In vivo and in vitro results were compared to those obtained by a TOMROP sequence in the same acquisition time

Using ordinal logistic regression to evaluate the performance of laser-Doppler predictions of burn-healing time

Background Laser-Doppler imaging (LDI) of cutaneous blood flow is beginning to be used by burn surgeons to predict the healing time of burn wounds; predicted healing time is used to determine wound treatment as either dressings or surgery. In this paper, we do a statistical analysis of the performance of the technique. Methods We used data from a study carried out by five burn centers: LDI was done once between days 2 to 5 post burn, and healing was assessed at both 14 days and 21 days post burn. Random-effects ordinal logistic regression and other models such as the continuation ratio model were used to model healing-time as a function of the LDI data, and of demographic and wound history variables. Statistical methods were also used to study the false-color palette, which enables the laser-Doppler imager to be used by clinicians as a decision-support tool. Results Overall performance is that diagnoses are over 90% correct. Related questions addressed were what was the best blood flow summary statistic and whether, given the blood flow measurements, demographic and observational variables had any additional predictive power (age, sex, race, % total body surface area burned (%TBSA), site and cause of burn, day of LDI scan, burn center). It was found that mean laser-Doppler flux over a wound area was the best statistic, and that, given the same mean flux, women recover slightly more slowly than men. Further, the likely degradation in predictive performance on moving to a patient group with larger %TBSA than those in the data sample was studied, and shown to be small. Conclusion Modeling healing time is a complex statistical problem, with random effects due to multiple burn areas per individual, and censoring caused by patients missing hospital visits and undergoing surgery. This analysis applies state-of-the art statistical methods such as the bootstrap and permutation tests to a medical problem of topical interest. New medical findings are that age and %TBSA are not important predictors of healing time when the LDI results are known, whereas gender does influence recovery time, even when blood flow is controlled for. The conclusion regarding the palette is that an optimum three-color palette can be chosen 'automatically', but the optimum choice of a 5-color palette cannot be made solely by optimizing the percentage of correct diagnoses