202 research outputs found

    Oxygen Reduction in Aqueous Phosphate Solutions. Properties of Fe, Co, Ni, Cu Impregnated Polyphthalocyanines

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    The oxygen reduction process has been investigated at room temperature on polyphthalocyanines of Fe, Co, Ni and Cu prepared similarly impregnated in acetylene black on a graphite support. Fe polyphthalocyanine is the most active. Investigations v ersus pH and temperature have shown that the limiting process is a 4 electron transfer

    Ultrastructural studies of the mode of penetration byPhoma macdonaldiiin sunflower seedlings

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    An ultrastructural investigation of the artificial inoculation of sunflower with Phoma macdonaldii conidia was undertaken using light, scanning, and transmission electron microscopy to elucidate the host-parasite relationship. The behavior of the conidia deposited on the cotyledon petiole was investigated at various time intervals after inoculation. Conidia adhesion and germination were observed first. The cotyledon petiole was invaded by the fungus directly through the cuticle and via stomata. Externally, the spore and germ tube were covered with a mucilaginous polysaccharide sheath of a cotton-like appearance and of variable thickness. At the time of penetration, the host cuticle was perforated mechanically. The cuticle was slightly depressed and no enzymatic alteration could be observed. The fungus did not form appressoria on the surface of the host tissues but developed an infection peg. As soon as the cuticle barrier was crossed, the fungus rapidly colonized the host parietal layer. In a first step, the plasmalemma of the host cell appeared to be stuck against the cell wall. As soon as the fungus passed through the epidermal cell wall to reach the host cytoplasm, the plasmalemma was disrupted, and the subsequent rapid breakdown of cell integrity favored the colonization of the tissues by the pathogen

    Contribution of local agrobiodiversity to complementary foods for 6 to 23 months old children in southern rural Benin

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    In rural Benin, malnutrition, especially micronutrient deficiencies, contrasts with a rich agrobiodiversity that abounds in cultivated or wild foods that are potential sources of micronutrients. This paradox leads us to examine the role of local agrobiodiversity in the diet of children living in two agroecological zones of southern Benin. This study involved 1,263 children aged 6-23 months from 17 randomly selected villages in Southern Benin. A multiple-pass 24-h recall method on two non-consecutive days with the estimation of the consumed portions was used to collect dietary intake data. Semistructured questionnaires were used to collect socioeconomic and demographic data to explore factors driving agrobiodiversity food consumption, especially wild foods. Nonparametric analyses based on gamma distribution were performed to establish the effect of wild food consumption on vitamin A, calcium, iron, and zinc intakes. Conditional inference tree-classification models were performed to identify factors driving wild food consumption. Among a total of 48 local foods that were reported as consumed by children, 11 were from wild species. The contributions of total local agrobiodiversity to nutrient intake of complementary foods was between 49% (calcium) and 98% (vitamin A). Cultivated species contributed to local agrobiodiversity foods for 57% (calcium) and 96 % (zinc). The semi-domesticated species have a contribution of between 2% (zinc) and 35% (calcium) to nutrient intake. Wild species contribution to nutrient intake was between 1% (zinc) and 9% for vitamin C. Wild foods consumption correlated significantly and positively with calcium and vitamin A intakes among children. Sociolinguistic factors such as ethnicity and religion of the household head were determinants of wild food consumption. These findings suggest that sensitization on the nutritional importance of the wild foods including socio-linguistic factors may be necessary to promote wild foods’ consumption. This could be a good strategy to promote healthy diets in local communities.&nbsp

    Our Fluid Nation: The Impact of Fluid Dynamics in the UK

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    Fluid dynamics is a major UK industrial and research strength, and is critical to many applications. Fluid dynamics is an enabling technology for industry sectors as diverse as transport, healthcare technologies, marine and energy. It plays a key role in the most important challenges facing today’s society, including the drive to net zero, understanding disease and predicting weather and climate. For the first time, this report evaluates the direct contribution that fluid dynamics makes to the UK economy, highlighting the breadth of industry sectors where fluid dynamics is a critical part of business. The analysis provides key metrics, including the revenue associated with fluid dynamics activities, the size and distribution of the workforce providing these essential skills, the gross value added (GVA) to the UK economy, and the scale of research investment

    Dietary patterns of adults living in Ouagadougou and their association with overweight

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    <p>Abstract</p> <p>Background</p> <p>Urbanization in developing countries comes along with changes in food habits and living conditions and with an increase in overweight and associated health risks. The objective of the study was to describe dietary patterns of adults in Ouagadougou and to study their relationship with anthropometric status of the subjects.</p> <p>Methods</p> <p>A qualitative food frequency questionnaire was administered to 1,072 adults living in two contrasted districts of Ouagadougou. Dietary patterns were defined by principal component analysis and described by multivariate analysis. Logistic regression was used to study their association with overweight.</p> <p>Results</p> <p>The diet was mainly made of cereals, vegetables and fats from vegetable sources. The two first components of the principal component analysis were interpreted respectively as a "snacking" score and as a "modern foods" score. Both scores were positively and independently associated with the economic level of households and with food expenditures (p ≤ 0.001 for both). The "snacking" score was higher for younger people (p = 0.004), for people having a formal occupation (p = 0.006), for those never married (p = 0.005), whereas the "modern foods" score was associated with ethnic group (p = 0.032) and district of residence (p < 0.001). Thirty-six percent of women and 14.5% of men were overweight (Body Mass Index > 25 kg/m<sup>2</sup>). A higher "modern foods" score was associated with a higher prevalence of overweight when confounding factors were accounted for (OR = 1.19 [95% CI 1.03-1.36]) but there was no relationship between overweight and the "snacking" score.</p> <p>Conclusions</p> <p>Modernisation of types of foods consumed was associated with the living conditions and the environment and with an increased risk of overweight. This should be accounted for to promote better nutrition and prevent non communicable diseases.</p

    Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis

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    Background Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy. Methods We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance. Results We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography. Conclusion Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data

    A Digital Framework to Build, Visualize and Analyze a Gene Expression Atlas with Cellular Resolution in Zebrafish Early Embryogenesis

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    A gene expression atlas is an essential resource to quantify and understand the multiscale processes of embryogenesis in time and space. The automated reconstruction of a prototypic 4D atlas for vertebrate early embryos, using multicolor fluorescence in situ hybridization with nuclear counterstain, requires dedicated computational strategies. To this goal, we designed an original methodological framework implemented in a software tool called Match-IT. With only minimal human supervision, our system is able to gather gene expression patterns observed in different analyzed embryos with phenotypic variability and map them onto a series of common 3D templates over time, creating a 4D atlas. This framework was used to construct an atlas composed of 6 gene expression templates from a cohort of zebrafish early embryos spanning 6 developmental stages from 4 to 6.3 hpf (hours post fertilization). They included 53 specimens, 181,415 detected cell nuclei and the segmentation of 98 gene expression patterns observed in 3D for 9 different genes. In addition, an interactive visualization software, Atlas-IT, was developed to inspect, supervise and analyze the atlas. Match-IT and Atlas-IT, including user manuals, representative datasets and video tutorials, are publicly and freely available online. We also propose computational methods and tools for the quantitative assessment of the gene expression templates at the cellular scale, with the identification, visualization and analysis of coexpression patterns, synexpression groups and their dynamics through developmental stages
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