Microstructure and mechanical behavior in dissimilar 13Cr/2205 stainless steel welded pipes

Thiswork aims to investigate the microstructure and themechanical behavior of dissimilar 13Cr Supermartensitic/2205 Duplex stainless steelwelded pipes. A wide variety ofmicrostructures resulting fromboth solidification and solid state transformation is induced by the fusion welding process across the weld joint. The tensile tests show that the deformation process of the dissimilarweld joint ismainly controlled by the two basematerials: the duplex steel at the beginning of the deformation and the supermartensitic one at its end. This is confirmed by the microtensile tests showing the overmatching effect of the weld metal. The fatigue tests conducted on dissimilar welded specimens led us to conclude that the weld metal is considered as a weak link of the weld joint in the high cycle fatigue regime. This is supported by its lower fatigue limit compared to the two basematerials that exhibit a similar fatigue behavio

STABILITY AND EXTENT OF RESISTANCE OF COWPEA LINES TO FLOWER BUD THRIPS IN UGANDA

Cowpea ( Vigna unguiculata (L.) Walp.) is a legume attacked by several field insect pests, with flower thrips ( Megalurothrips sjostedti Trybom) being the most damaging. It causes 20 to 100% yield losses. Cowpea constitutes an important source of protein for resource poor households in Africa. The objective of this study was to identify cowpea lines that are resistant to flower thrips as a step in developing sustainable thrips management strategies. Seventy two cowpea cultivars were screened in three locations and two rainy seasons in Uganda, for thrips damage and yield components. Up to 11 cultivars (IT2841*Brown (1.50), MU20B (1.58), EBELAT*NE39 (1.61), WC17 (1.63), WC29 (1.65), MU24C (1.65), WC5 (1.66), NE46 (1.67), WC30 (1.68), NE67 (1.69), and NE51 (1.71)) were the most resistant and stable across locations. However, thrips damage was negatively correlated with the number of days to flowering (r = -0.32), indicating that the resistance in the cultivars was explained by the flower thrips infestation escape due to later flowering. Cultivar MU9 was high yielding (813.87 kg ha-1) and the most adapted genotype to all the locations; while cultivars WC26, NE48, and NE5 were the most adapted to Arua and Serere, and WC48A was the most adapted to Makerere University Agricultural Research Institute, Kabanyolo (MUARIK). There is potential of finding resistance sources in the cultivars tested.Le ni\ue9b\ue9 ( Vigna unguiculata (L.) Walp.) est une l\ue9gumineuse attaqu\ue9e par plusieurs insectes au champ avec thrips ( Megalurothrips sjostedti Trybom) le plus nuisible causant 20-100% de perte de rendement. Le ni\ue9b\ue9 constitue une source de prot\ue9ine bon-march\ue9 pour beaucoup de pauvres m\ue9nages en Afrique. L\u2019objectif de cette \ue9tude \ue9tait d\u2019identifier des vari\ue9t\ue9s plus r\ue9sistantes au thrips pour le d\ue9veloppement des strat\ue9gies de lutte durable. Soixante-douze vari\ue9t\ue9s du ni\ue9b\ue9 ont \ue9t\ue9 \ue9valu\ue9es dans trois environnements pendant deux saisons en Uganda pour les dommages, le rendement et ses composantes. Les donn\ue9es ont \ue9t\ue9 soumises aux analyses de variance et biplot de l\u2019effet de g\ue9notype et l\u2019interaction entre g\ue9notype et environnement (GGE). Les r\ue9sultats ont montr\ue9 un effet significatif (P<0.001) de l\u2019interaction entre g\ue9notype, environnement pour les scores de dommages caus\ue9s par thrips. Les vari\ue9t\ue9s les plus r\ue9sistantes et stables \ue9taient IT2841*Brown (1.50), MU20B (1.58), EBELAT*NE39 (1.61), WC17 (1.63), WC29 (1.65), MU24C (1.65), WC5 (1.66), NE46 (1.67), WC30 (1.68), NE67 (1.69), and NE51 (1.71). Toutefois, une corr\ue9lation n\ue9gative (r = -0.32) a \ue9t\ue9 observ\ue9e entre les scores de dommage et le nombre de jours de floraison indiquant que la r\ue9sistance observ\ue9e, \ue9tait due \ue0 un \ue9chappement par une floraison tardive. Le cultivar MU9 avait le rendement le plus \ue9lev\ue9 (813, 87 kg ha-1) et constituait le plus adapt\ue9 aux diff\ue9rents environnements alors que les cultivars WC26, NE48, and NE5 \ue9taient les plus adapt\ue9s \ue0 Arua et Serere, et WC48A \ue9tait le plus adapt\ue9 \ue0 l\u2019Institut de Recherches Agricoles de l\u2019Universit\ue9 de Makerere, Kabanyolo (MUARIK). Il y a potentiel de trouver de source de r\ue9sistance parmi les vari\ue9t\ue9s \ue9valu\ue9es

Genetic diversity and population structure of Peronosclerospora sorghi isolates of Sorghum in Uganda

Sorghum is the third most important staple cereal crop in Uganda after maize and millet. Downy mildew disease is one of the most devastating fungal diseases which limits the production and productivity of the crop. The disease is caused by an obligate fungus, Peronosclerospora sorghi (Weston & Uppal) with varying symptoms. Information on the genetic diversity and population structure of P.sorghi in sorghum is imperative for the screening and selection for resistant genotypes and further monitoring possible mutant(s) of the pathogen. Isolates of P. sorghi infecting sorghum are difficult to discriminate when morphological descriptors are used. The use of molecular markers is efficient, and reliably precised for characterizing P. sorghi isolates. This study was undertaken to assess the level of genetic diversity and population structure that exist in P. sorghi isolates in Uganda. A total of 195 P. sorghi isolates, sampled from 13 different geographic populations from 10 different regions (agro-ecological zones) was used. Eleven (11) molecular markers, comprising of four Random amplified microsatellite (RAM) and seven (7) Inter-Simple Sequence Repeat (ISSR) markers were used in this study. The analysis of molecular variation (AMOVA) based on 11 microsatellite markers showed significant (P < 0.001) intra-population (88.9 %, PhiPT = 0.111) and inter-population (8.4 %, PhiPR = 0.083) genetic variation, while the genetic variation among regions (2.7 %, PhiRT = 0.022) was not significant. The highest genetic similarity value (0.987 = 98.7 %) was recorded between Pader and Lira populations and the lowest genetic similarity (0.913 = 91.3 %) was observed between Namutumba and Arua populations. The mean Nei's genetic diversity index (H) and Shannon Information Index (I) were 0.308 and 0.471 respectively. Seven distinct cluster groups were formed from the 195 P. sorghi isolates based on their genetic similarity. Mantel test revealed no association between genetic differentiation and geographical distance (R2 = 0.0026, p = 0.02) within the 13 geographic populations

A double-blind placebo-controlled trial of azithromycin to reduce mortality and improve growth in high-risk young children with non-bloody diarrhoea in low resource settings: the Antibiotics for Children with Diarrhoea (ABCD) trial protocol

Background Acute diarrhoea is a common cause of illness and death among children in low- to middle-income settings. World Health Organization guidelines for the clinical management of acute watery diarrhoea in children focus on oral rehydration, supplemental zinc and feeding advice. Routine use of antibiotics is not recommended except when diarrhoea is bloody or cholera is suspected. Young children who are undernourished or have a dehydrating diarrhoea are more susceptible to death at 90 days after onset of diarrhoea. Given the mortality risk associated with diarrhoea in children with malnutrition or dehydrating diarrhoea, expanding the use of antibiotics for this subset of children could be an important intervention to reduce diarrhoea-associated mortality and morbidity. We designed the Antibiotics for Childhood Diarrhoea (ABCD) trial to test this intervention. Methods ABCD is a double-blind, randomised trial recruiting 11,500 children aged 2–23 months presenting with acute non-bloody diarrhoea who are dehydrated and/or undernourished (i.e. have a high risk for mortality). Enrolled children in Bangladesh, India, Kenya, Malawi, Mali, Pakistan and Tanzania are randomised (1:1) to oral azithromycin 10 mg/kg or placebo once daily for 3 days and followed-up for 180 days. Primary efficacy endpoints are all-cause mortality during the 180 days post-enrolment and change in linear growth 90 days post-enrolment. Discussion Expanding the treatment of acute watery diarrhoea in high-risk children to include an antibiotic may offer an opportunity to reduce deaths. These benefits may result from direct antimicrobial effects on pathogens or other incompletely understood mechanisms including improved nutrition, alterations in immune responsiveness or improved enteric function. The expansion of indications for antibiotic use raises concerns about the emergence of antimicrobial resistance both within treated children and the communities in which they live. ABCD will monitor antimicrobial resistance. The ABCD trial has important policy implications. If the trial shows significant benefits of azithromycin use, this may provide evidence to support reconsideration of antibiotic indications in the present World Health Organization diarrhoea management guidelines. Conversely, if there is no evidence of benefit, these results will support the current avoidance of antibiotics except in dysentery or cholera, thereby avoiding inappropriate use of antibiotics and reaffirming the current guidelines. Trial registration Clinicaltrials.gov, NCT03130114. Registered on April 26 2017

Population-based prevalence survey of follicular trachoma and trachomatous trichiasis in the Casamance region of Senegal.

BACKGROUND: Trachoma, caused by ocular infection with Chlamydia trachomatis, is the leading infectious cause of blindness worldwide. We conducted the first population-based trachoma prevalence survey in the Casamance region of Senegal to enable the Senegalese National Eye Care Programme (NECP) to plan its trachoma control activities. The World Health Organization (WHO) guidelines state that any individual with trachomatous trichiasis (TT) should be offered surgery, but that surgery should be prioritised where the prevalence is >0.1%, and that districts and communities with a trachomatous inflammation, follicular (TF) prevalence of ≥10% in 1-9 year-olds should receive mass antibiotic treatment annually for a minimum of three years, along with hygiene promotion and environmental improvement, before re-assessing the prevalence to determine whether treatment can be discontinued (when TF prevalence in 1-9 year-olds falls 1% in all districts. CONCLUSION: With a prevalence <5%, TF does not appear to be a significant public health problem in this region. However, TF monitoring and surveillance at sub-district level will be required to ensure that elimination targets are sustained and that TF does not re-emerge as a public health problem. TT surgery remains the priority for trachoma elimination efforts in the region, with an estimated 1819 TT surgeries to conduct

Common, low-frequency, rare, and ultra-rare coding variants contribute to COVID-19 severity

The combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management. © 2021, The Author(s)

Evolution of microstructure and crystallographic texture during dissimilar friction stir welding of duplex stainless steel to low carbon-manganese structural steel

Electron backscattered diffraction (EBSD) was used to analyze the evolution of microstructure and crystallographic texture during friction stir welding of dissimilar type 2205 duplex stainless steel (DSS) to type S275 low carbon-manganese structural steel. The results of microstructural analyses show that the temperature in the center of stirred zone reached temperatures between Ac 1 and Ac 3 during welding, resulting in a minor ferrite-to-austenite phase transformation in the S275 steel, and no changes in the fractions of ferrite and austenite in the DSS. Temperatures in the thermomechanically affected and shoulder-affected zones of both materials, in particular toward the root of the weld, did not exceed the Ac 1 of S275 steel. The shear generated by the friction between the material and the rotating probe occurred in austenitic/ferritic phase field of the S275 and DSS. In the former, the transformed austenite regions of the microstructure were transformed to acicular ferrite, on cooling, while the dual-phase austenitic/ferritic structure of the latter was retained. Studying the development of crystallographic textures with regard to shear flow lines generated by the probe tool showed the dominance of simple shear components across the whole weld in both materials. The ferrite texture in S275 steel was dominated by D 1, D 2, E, E¯ , and F, where the fraction of acicular ferrite formed on cooling showed a negligible deviation from the texture for the ideal shear texture components of bcc metals. The ferrite texture in DSS was dominated by D 1, D 2, I, I¯ , and F, and that of austenite was dominated by the A, A¯ , B, and B¯ of the ideal shear texture components for bcc and fcc metals, respectively. While D 1, D 2, and F components of the ideal shear texture are common between the ferrite in S275 steel and that of dual-phase DSS, the preferential partitioning of strain into the ferrite phase of DSS led to the development of I and I¯ components in DSS, as opposed to E and E¯ in the S275 steel. The formations of fine and ultrafine equiaxed grains were observed in different regions of both materials that are believed to be due to strain-induced continuous dynamic recrystallization (CDRX) in ferrite of both DSS and S275 steel, and discontinuous dynamic recrystallization (DDRX) in austenite phase of DSS