469 research outputs found

    Evidence of the presence of low pathogenic avian influenza a viruses inwild waterfowl in 2018 in south africa

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    Avian influenza viruses are pathogens of global concern to both animal and human health. Wild birds are the natural reservoir of avian influenza viruses and facilitate virus transport over large distances. Surprisingly, limited research has been performed to determine avian influenza host species and virus dynamics in wild birds on the African continent, including South Africa. This study described the first wild bird surveillance efforts for influenza A viruses in KwaZulu-Natal Province in South Africa after the 2017/2018 outbreak with highly pathogenic avian influenza virus H5N8 in poultry. A total of 550 swab samples from 278 migratory waterfowl were tested using real-time RT-PCR methods. Two samples (0.7%) were positive for avian influenza virus based on the matrix gene real-time RT-PCR but were negative for the hemagglutinin subtypes H5 and H7. Unfortunately, no sequence information or viable virus could be retrieved from the samples. This study shows that avian influenza viruses are present in the South African wild bird population, emphasizing the need for more extensive surveillance studies to determine the South African avian influenza gene pool and relevant local host species

    Sorting Nexin 24 is required for α-granule biogenesis and cargo delivery in megakaryocytes

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    Germline defects affecting the DNA-binding domain of the transcription factor FLI1 are associated with a bleeding disorder that is characterised by the presence of large, fused α-granules in platelets. We investigated whether the genes showing abnormal expression in FLI1-deficient platelets could be involved in platelet α-granule biogenesis by undertaking transcriptome analysis of control platelets and platelets harbouring a DNA-binding variant of FLI1. Our analysis identified 2276 transcripts that were differentially expressed in FLI1- deficient platelets. Functional annotation clustering of the coding transcripts revealed significant enrichment for gene annotations relating to protein transport, and identified Sorting nexin 24 (SNX24) as a candidate for further investigation. Using an iPSC-derived megakaryocyte model, SNX24 expression was found to be increased during the early stages of megakaryocyte differentiation and downregulated during proplatelet formation, indicating tight regulatory control during megakaryopoiesis. CRISPR-Cas9 mediated knockout (KO) of SNX24 led to decreased expression of immature megakaryocyte markers, CD41 and CD61, and increased expression of the mature megakaryocyte marker CD42b (p=0.0001), without affecting megakaryocyte polyploidisation, or proplatelet formation. Electron microscopic analysis revealed an increase in empty membrane-bound organelles in SNX24 KO megakaryocytes, a reduction in α-granules and an absence of immature and mature multivesicular bodies, consistent with a defect in the intermediate stage of α-granule maturation. Co-localisation studies showed that SNX24 associates with each compartment of α-granule maturation. Reduced expression of CD62P and VWF was observed in SNX24 KO megakaryocytes. We conclude that SNX24 is required for α-granule biogenesis and intracellular trafficking of α-granule cargo within megakaryocytes

    The Residual Stress Relaxation Behavior of Weldments During Cyclic Loading

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    Accurate measurement of residual stress is necessary to obtain reliable predictions of fatigue lifetime and enable estimation of time-to-facture for any given stress level. In this article, relaxation of welding residual stresses as a function of cyclic loading was documented on three common steels: AISI 1008, ASTM A572, and AISI 4142. Welded specimens were subjected to cyclic bending (R = 0.1) at different applied stresses, and the residual stress relaxation existing near the welds was measured as a function of cycles. The steels exhibited very different stress relaxation behaviors during cyclic loadings, which can be related to the differences in the microstructures of the specimens. A phenomenological model, which treats dislocation motion during cyclic loading as being analogous to creep of dislocations, is proposed for estimation of the residual stress relaxation

    The association of female sex with management and mortality in patients with Staphylococcus aureus bacteraemia

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    Objectives: The association of biological female sex with outcome in patients with Staphylococcus aureus bacteraemia remains unresolved. The aim of this study was to determine the independent association of female sex with management and mortality in patients with S. aureus bacteraemia.Methods: This is a post hoc analysis of prospectively collected data from the S. aureus Bacteraemia Group Prospective Cohort Study. Adult patients with monomicrobial S. aureus bacteraemia at Duke University Medical Center were enrolled from 1994 to 2020. Univariable and multivariable Cox regression analyses were performed to assess differences in management and mortality between females and males.Results: Among 3384 patients with S. aureus bacteraemia, 1431 (42%) were women. Women were, as compared with men, more often Black (581/1431 [41%] vs. 620/1953 [32%], p < 0.001), haemodialysis dependent (309/1424 [22%] vs. 334/1940 [17%], p 0.001) and more likely to be infected with methicillinresistant S. aureus (MRSA) (697/1410 [49%] MRSA in women vs. 840/1925 [44%] MRSA in men, p 0.001). Women received shorter durations of antimicrobial treatment (median 24 [interquartile range 14-42] vs. 28 [interquartile range 14-45] days, p 0.005), and were less likely to undergo transesophageal echocardiography as compared with men (495/1430 [35%] vs. 802/1952 [41%], p < 0.001). Despite these differences, female sex was not associated with 90-day mortality in either univariable (388/1431 [27%] in women vs. 491/1953 [25%] in men, p 0.204) or multivariable analysis (adjusted hazard ratio for women 0.98 [95% CI, 0.85-1.13]).Discussion: Despite significant differences in patient characteristics, disease characteristics, and management, women and men with S. aureus bacteraemia have a similar mortality risk. Annette C. Westgeest, Clin Microbiol Infect 2023;29:1182Immunogenetics and cellular immunology of bacterial infectious disease

    Towards good practice guidelines for the contour method of residual stress measurement

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    Accurate measurement of residual stress in metallic components using the contour method relies on the achievement of a good quality cut, on the appropriate measurement of the deformed cut surface and on the robust analysis of the measured data. There is currently no published standard or code of practice for the contour method. As a first step towards such a standard, this study draws on research investigations addressing the three main steps in the method: how best to cut the specimens; how to measure the deformation contour of the cut surface; and how to analyse the data. Good practice guidance is provided throughout the text accompanied by more detailed observations and advice tabulated in Appendi

    Soil penetration resistance analysis by multivariate and geostatistical methods

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    The penetration resistance (PR) is a soil attribute that allows identifies areas with restrictions due to compaction, which results in mechanical impedance for root growth and reduced crop yield. The aim of this study was to characterize the PR of an agricultural soil by geostatistical and multivariate analysis. Sampling was done randomly in 90 points up to 0.60 m depth. It was determined spatial distribution models of PR, and defined areas with mechanical impedance for roots growth. The PR showed a random distribution to 0.55 and 0.60 m depth. PR in other depths analyzed showed spatial dependence, with adjustments to exponential and spherical models. The cluster analysis that considered sampling points allowed establishing areas with compaction problem identified in the maps by kriging interpolation. The analysis with main components identified three soil layers, where the middle layer showed the highest values of PR.La resistencia a la penetración (RP) es un atributo del suelo que permite identificar zonas con restricciones debido a la compactación, que se traduce en impedancia mecánica para el desarrollo de las raíces y en una menor productividad de los cultivos. El objetivo del presente trabajo fue caracterizar la RP de un suelo agrícola, mediante análisis geoestadístico y multivariado. El muestreo se realizó de manera aleatoria en 90 puntos, hasta una profundidad de 0,60 m. Se determinaron los modelos de distribución espacial de la RP y se delimitaron áreas con problemas de impedancia mecánica de las raíces. La RP presentó distribución aleatoria a 0,55 y 0,60 m de profundidad. La RP en las otras profundidades analizadas mostraron dependencia espacial, con ajustes a modelos exponenciales y esféricos. El análisis jerárquico que consideró puntos de muestreo, permitió establecer zonas con problemas de compactación, identificadas en los mapas obtenidos mediante interpolación por kriging. El análisis de componentes principales permitió identificar tres capas de suelo, donde la capa intermedia fue la que presentó los mayores valores de RP

    Association between hyperglycaemia in pregnancy and growth of offspring in early childhood: The PANDORA study

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    First published: 29 May 2022Background: Few studies have assessed whether children exposed to in utero hyperglycaemia experience different growth trajectories compared to unexposed children.Objectives:To assess association of type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) with early childhood weight, length/height and body mass index(BMI) trajectories, and with timing and magnitude of peak BMI in infancy.Methods:PANDORA is a birth cohort recruited from an Australian hyperglycaemia in pregnancy register, and women with normoglycaemia recruited from the community.Offspring growth measures were obtained from health records over a median follow-up of 3.0 years (interquartile range 1.9–4.0). This analysis included children born to Aboriginal mothers with in utero normoglycaemia (n=95), GDM (n=228) or T2D(n=131). Growth trajectories (weight, length/height and BMI) were estimated usinglinear mixed models with cubic spline functions of child age. Results:After adjustment for maternal factors (age, BMI, parity, smoking, and socio-economic measures) and child factors (age, gestational age at birth, and sex), children born to mothers with T2D or GDM had lower weight, length/height and BMI trajectories in infancy than children born to mothers with normoglycaemia, but similar weight and BMI by completion of follow-up. Children exposed to T2D had lower mean peak BMI 17.6 kg/m2(95% confidence interval [CI] 17.3–18.0) than childrenexposed to normoglycaemia (18.6 kg/m2[18.1–18.9]) (p=0.001). Conclusions: Maternal hyperglycaemia was associated with differences in early child-hood growth trajectories after adjustment for maternal BMI. Exploration of associations between in utero hyperglycaemia exposure and growth trajectories into later childhood is required.Angela Titmuss, Danielle K. Longmore, Federica Barzi, Elizabeth L. M. Barr, Vanya Webster, Anna Wood, Alison Simmonds, Alex D. H. Brown, Christine Connors, Jacqueline A. Boyle, Jeremy Oats, H. David McIntyre, Jonathan E. Shaw, Maria E. Craig, Louise J. Maple-Brown, the PANDORA Study Research Tea

    Association between maternal hyperglycemia in pregnancy and offspring anthropometry in early childhood: the pandora wave 1 study

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    Background: In-utero hyperglycemia exposure influences later cardiometabolic risk, although few studies include women with pre-existing type 2 diabetes (T2D) or assess maternal body mass index (BMI) as a potential confounder. Objective: To explore the association of maternal T2D and gestational diabetes mellitus (GDM) with childhood anthropometry, and the influence of maternal BMI on these associations. Methods: The PANDORA cohort comprises women (n = 1138) and children (n = 1163). Women with GDM and T2D were recruited from a hyperglycemia in pregnancy register, and women with normoglycemia from the community. Wave 1 follow-up included 423 children, aged 1.5–5 years (median follow-up age 2.5 years). Multivariable linear regression assessed associations between maternal antenatal variables, including BMI and glycemic status, with offspring anthropometry (weight, height, BMI, skinfold thicknesses, waist, arm and head circumferences). Results: Greater maternal antenatal BMI was associated with increased anthropometric measures in offspring independent of maternal glycemic status. After adjustment, including for maternal BMI, children exposed to maternal GDM had lower mean weight (−0.54 kg, 95% CI: −0.99, −0.11), BMI (−0.55 kg/m2, 95% CI: −0.91, −0.20), head (−0.52 cm, 95% CI: −0.88, −0.16) and mid-upper arm (−0.32 cm, 95% CI: −0.63, −0.01) circumferences, and greater mean suprailiac skinfold (0.78 mm, 95% CI: 0.13, 1.43), compared to children exposed to normoglycemia. Adjustment for maternal BMI strengthened the negative association between GDM and child weight, BMI and circumferences. Children exposed to maternal T2D had smaller mean head circumference (−0.82 cm, 95% CI: −1.33, −0.31) than children exposed to normoglycemia. Maternal T2D was no longer associated with greater child mean skinfolds (p = 0.14) or waist circumference (p = 0.18) after adjustment for maternal BMI. Conclusions: Children exposed to GDM had greater suprailiac skinfold thickness than unexposed children, despite having lower mean weight, BMI and mid-upper arm circumference, and both GDM and T2D were associated with smaller mean head circumference. Future research should assess whether childhood anthropometric differences influence lifetime cardiometabolic and neurodevelopmental risk.Angela Titmuss, Federica Barzi, Elizabeth L. M. Barr, Vanya Webster, Anna Wood, Joanna Kelaart, Marie Kirkwood, Christine Connors, Jacqueline A. Boyle, Elizabeth Moore, Jeremy Oats, H. David McIntyre, Paul Zimmet, Alex D. H. Brown, Jonathan E. Shaw, Maria E. Craig, and Louise J. Maple-Brow
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