F4+ ETEC infection and oral immunization with F4 fimbriae elicits an IL-17-dominated immune response

Enterotoxigenic Escherichia coli (ETEC) are an important cause of post-weaning diarrhea (PWD) in piglets. Porcine-specific ETEC strains possess different fimbrial subtypes of which F4 fimbriae are the most frequently associated with ETEC-induced diarrhea in piglets. These F4 fimbriae are potent oral immunogens that induce protective F4-specific IgA antibody secreting cells at intestinal tissues. Recently, T-helper 17 (Th17) cells have been implicated in the protection of the host against extracellular pathogens. However, it remains unknown if Th17 effector responses are needed to clear ETEC infections. In the present study, we aimed to elucidate if ETEC elicits a Th17 response in piglets and if F4 fimbriae trigger a similar response. F4+ ETEC infection upregulated IL-17A, IL-17F, IL-21 and IL-23p19, but not IL-12 and IFN-γ mRNA expression in the systemic and mucosal immune system. Similarly, oral immunization with F4 fimbriae triggered a Th17 signature evidenced by an upregulated mRNA expression of IL-17F, RORγt, IL-23p19 and IL-21 in the peripheral blood mononuclear cells (PBMCs). Intriguingly, IL-17A mRNA levels were unaltered. To further evaluate this difference between systemic and mucosal immune responses, we assayed the cytokine mRNA profile of F4 fimbriae stimulated PBMCs. F4 fimbriae induced IL-17A, IL-17F, IL-22 and IL-23p19, but downregulated IL-17B mRNA expression. Altogether, these data indicate a Th17 dominated response upon oral immunization with F4 fimbriae and F4+ ETEC infection. Our work also highlights that IL-17B and IL-17F participate in the immune response to protect the host against F4+ ETEC infection and could aid in the design of future ETEC vaccines

Dissemination of Cephalosporin Resistance Genes between Escherichia coli Strains from Farm Animals and Humans by Specific Plasmid Lineages

Third-generation cephalosporins are a class of β-lactam antibiotics that are often used for the treatment of human infections caused by Gram-negative bacteria, especially Escherichia coli. Worryingly, the incidence of human infections caused by third-generation cephalosporin-resistant E. coli is increasing worldwide. Recent studies have suggested that these E. coli strains, and their antibiotic resistance genes, can spread from food-producing animals, via the food-chain, to humans. However, these studies used traditional typing methods, which may not have provided sufficient resolution to reliably assess the relatedness of these strains. We therefore used whole-genome sequencing (WGS) to study the relatedness of cephalosporin-resistant E. coli from humans, chicken meat, poultry and pigs. One strain collection included pairs of human and poultry-associated strains that had previously been considered to be identical based on Multi-Locus Sequence Typing, plasmid typing and antibiotic resistance gene sequencing. The second collection included isolates from farmers and their pigs. WGS analysis revealed considerable heterogeneity between human and poultry-associated isolates. The most closely related pairs of strains from both sources carried 1263 Single-Nucleotide Polymorphisms (SNPs) per Mbp core genome. In contrast, epidemiologically linked strains from humans and pigs differed by only 1.8 SNPs per Mbp core genome. WGS-based plasmid reconstructions revealed three distinct plasmid lineages (IncI1- and IncK-type) that carried cephalosporin resistance genes of the Extended-Spectrum Beta-Lactamase (ESBL)- and AmpC-types. The plasmid backbones within each lineage were virtually identical and were shared by genetically unrelated human and animal isolates. Plasmid reconstructions from short-read sequencing data were validated by long-read DNA sequencing for two strains. Our findings failed to demonstrate evidence for recent clonal transmission of cephalosporin-resistant E. coli strains from poultry to humans, as has been suggested based on traditional, low-resolution typing methods. Instead, our data suggest that cephalosporin resistance genes are mainly disseminated in animals and humans via distinct plasmids

The deciding role of texture on ductility in a Ce containing Mg alloy

This is the first successful attempt to produce Mg-Ce alloys of different texture through different processing routes while keeping the grain size and grain size distribution same. Tensile data shows that contribution of texture to ductility enhancement is primary and that of grain refinement is secondary. The texture resulting from multi-axial forging of extruded billets followed by annealing exhibits the highest ductility (similar to 40%) at room temperature. (C) 2015 Elsevier B.V. All rights reserved

Ductility enhancement in Mg-0.2%Ce alloys

Ductility of Mg alloys can be enhanced by alloying, controlling the grain size and randomizing the texture. In this study, Mg-0.2%Ce alloys were processed using rolling, multi-axial forging (MAF) and equal channel angular pressing (ECAP) to fabricate three different textured samples from the same alloy. The samples were further annealed to produce similar grain size without altering texture. Rolled sample had a strong basal (0001) texture, the MAF sample developed a weak (01 (12) over bar) (2) over bar3 (1) over bar2] texture component in addition to the basal texture and the ECAP sample exhibited a strong non-basal ((1) over bar2 (1) over bar3) (2) over bar 11 (1) over bar] texture component. The tensile properties, texture evolution and relative slip/twin activities in the samples were investigated experimentally and numerically. The tensile yield strength, ultimate strength and uniform elongation of the rolled, MAF and ECAP samples were 110MPa, 250MPa, 17%; 60MPa, 200MPa, 30% and 55MPa, 250MPa and 40%, respectively. The non-basal texture components in ECAP and MAF samples favored the formation of extension twins and pyr. <c+a> slip during tensile loading. Full field crystal plasticity finite element modelling (CPFEM) using the initial texture of the materials as input provided insights into the activation of different deformation modes and observed differences in hardening mechanisms as well as strain localization and premature failure of the rolled samples. CPFEM analysis confirms that Ce addition reduces the relative values of the critical resolved shear stress (CRSS) for the slip and twinning systems which, in turn, allows for texture modification during material fabrication. These, combined with the ability to control grain size in Mg-Ce alloy with excess Ce, provide options for ductility enhancement in Mg alloys. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Effect of temperature on microstructure and texture evolution during uniaxial tension of commercially pure titanium

Commercially pure (CP) titanium samples were subjected to uniaxial tension of 5, 15, 25, 35 and 45 elongation (%) at room temperature (298 K), 673 K and 873 K respectively. The texture and microstructure evolution as a function of temperature and elongation (%) were evaluated in the present study. The following observations were made: (i) twins of both {10 (1) over bar 2} type tensile twins and {11 (2) over bar 2} type compressive twins were significant during deformation at 298 K while at high temperatures, these twins were observed till 15 elongation (%) only; (ii) both the twins were mostly activated in the grains/orientations of high Schmid factor values, although these twins were also activated in some grains with low Schmid factor values; (iii) both grain refinement and mis-orientation developments as a function of elongation (%) was higher for the samples deformed at 298 K compared to those at 673 K and 873 K; (iv) The initial texture concentrated along (11 (2) over bar 5) 00 > was observed to be strengthened with progressive deformation irrespective of the temperature of deformation. However, the texture intensity was higher during deformation at high temperatures

Evolution of microstructure during hot deformation of pearlitic steel

Hot deformation of pearlitic steel was carried out to examine the overall deformation response to microstructural evolution. To understand the mechanisms operative during hot deformation, compression tests were carried out at various temperatures in the range 400(-)600 degrees C and strain rates in the range 0.001-10 s(-1). The flow curves were analyzed to examine the occurrence of dynamic recrystallization. The evolution of microstructure in hot deformed samples is analysed using EBSD

Mg/BN nanocomposites: Nano-BN addition for enhanced room temperature tensile and compressive response

The present study elucidates the effects of nanoscale boron nitride particles addition on the microstructural and mechanical characteristics of monolithic magnesium. Novel light-weight Mg nanocomposites containing 0.3, 0.6 and 1.2vol% nano-size boron nitride particulates were synthesized using the disintegrated melt deposition method followed by hot extrusion. Microstructural characterization of developed Mg/x-boron nitride composites revealed significant grain refinement due to the uniform distribution of nano-boron nitride particulates. Texture analysis of selected Mg-1.2 boron nitride nanocomposite showed an increase in the intensity of fiber texture alongside enhanced localized recrystallization when compared to monolithic Mg. Mechanical properties evaluation under indentation, tension and compression loading indicated superior response of Mg/x-boron nitride composites in comparison to pure Mg. The uniform distribution of nanoscale boron nitride particles and the modified crystallographic texture achieved due to the nano-boron nitride addition attributes to the superior mechanical characteristics of Mg/boron nitride nanocomposites

How do persons with dementia participate in decision making related to health and daily care? A multi-case study

Background Many countries have passed laws giving patients the right to participate in decisions about health care. People with dementia cannot be assumed to be incapable of making decisions on their diagnosis alone as they may have retained cognitive abilities. The purpose of this study was to gain a better understanding of how persons with dementia participated in making decisions about health care and how their family carers and professional caregivers influenced decision making. Methods This Norwegian study had a qualitative multi-case design. The triad in each of the ten cases consisted of the person with dementia, the family carer and the professional caregiver, in all 30 participants. Inclusion criteria for the persons with dementia were: (1) 67 years or older (2) diagnosed with dementia (3) Clinical Dementia Rating score 2, moderate dementia; (3) able to communicate verbally. The family carers and professional caregivers were then asked to participate. A semi-structured interview guide was used in interviews with family carers and professional caregivers. Field notes were written after participant observation of interactions between persons with dementia and professional caregivers during morning care or activities at a day centre. How the professional caregivers facilitated decision making was the focus of the observations that varied in length from 30 to 90 minutes. The data were analyzed using framework analysis combined with a hermeneutical interpretive approach. Results Professional caregivers based their assessment of mental competence on experience and not on standardized tests. Persons with dementia demonstrated variability in how they participated in decision making. Pseudo-autonomous decision making and delegating decision making were new categories that emerged. Autonomous decision making did occur but shared decision making was the most typical pattern. Reduced mental capacity, lack of available choices or not being given the opportunity to participate led to non-involvement. Not all decisions were based on logic; personal values and relationships were also considered. Conclusions Persons with moderate dementia demonstrated variability in how they participated in decision making. Optimal involvement was facilitated by positioning them as capable of influencing decisions, assessing decision-specific competence, clarifying values and understanding the significance of relationships and context