Effect of austempering parameters and manganese content on the machinability of austempered ductile iron produced using novel method

Austempered ductile iron is an innovative material obtained by subjecting it to an austempering heat treatment. The wide application of this material is because its properties are comparable to those of steel, which has a much lower weight. However, the machinability of this material is always a difficult task owing to its high hardness. This problem becomes more complex when a considerable amount of Mn is added. In this study, a novel two-step austempering heat treatment was performed on spheroidal graphite iron containing different amounts of manganese. Although the novel heat treatment method helps to obtain a superior combination of hardness and impact, its effect on machinability must be determined. This study provides the results of machinability tests carried out on austempered ductile iron with various manganese contents produced using the novel method. Scanning electron microscope images of the microstructures revealed a typical ausferrite structure with no segregation of manganese at the grain boundary. This is evident from the good tool life obtained in the machinability tests. Regression equations are fitted to determine the tool life and surface roughness for machining parameters with a range of values considered in this study. The results obtained have shown that till 1 wt% of manganese alloyed austempered ductile iron can be successfully produced using the novel heat treatment method. This helps to obtain the optimum combination of strength and impact properties

The Skin Microbiome in Psoriatic Arthritis: Methodology Development and Pilot Data

Background Skin microbiota are likely to be important in the development of conditions such as psoriatic arthritis. Profiling the bacterial community in the psosriatic plaques will contribute to our understanding of the role of the skin microbiome in these conditions. The aim of this work was to determine the optimum study design for work on the skin microbiome with use of the MiSeq platform. The objectives were to compare data generated from two platforms for two primer pairs in a low density mock bacterial community.<p></p> Methods DNA was obtained from two low density mock communities of 11 diverse bacterial strains (with and without human DNA supplementation) and from swabs taken from the skin of four healthy volunteers. The DNA was amplified with primer pairs covering hypervariable regions of the 16S rRNA gene: primers 63F and 519R (V1-V3), and 347F and 803R (V3-V4). The resultant libraries were indexed for the MiSeq and Roche454 platforms and sequenced. Both datasets were de-noised, cleaned of chimeras, and analysed by use of QIIME software (version 1.8.0).<p></p> Findings No significant difference in the diversity indices at the phylum and the genus level between the platforms was seen. Comparison of the diversity indices for the mock community data for the two primer pairs demonstrated that the V3-V4 hypervariable region had significantly better capture of bacterial diversity than did the V1-V3 region. Amplification with the same primer pairs showed strong concordance within each platform (98·9–99·8%), with negligible effect of spiked human DNA contamination. Comparison at the family level classification between samples processed on the MiSeq and Roche454 platforms using the V3-V4 hypervariable region also showed a high level of concordance (87%), although less so for the V1-V3 primers (10%). The pilot data from healthy volunteers were similar.<p></p> Interpretation Results obtained from the V3-V4 16S rRNA hypervariable region, sequencing on the MiSeq and Roche454 platforms, were concordant between replicates, and between each other. These findings suggest that the MiSeq platform, and these primers, is a comparable method for determining skin microbiota to the widely used Roche454 methodology.<p></p&gt

Optimisation of methods for bacterial skin microbiome investigation: primer selection and comparison of the 454 versus MiSeq platform

Abstract Background The composition of the skin microbiome is predicted to play a role in the development of conditions such as atopic eczema and psoriasis. 16S rRNA gene sequencing allows the investigation of bacterial microbiota. A significant challenge in this field is development of cost effective high throughput methodologies for the robust interrogation of the skin microbiota, where biomass is low. Here we describe validation of methodologies for 16S rRNA (ribosomal ribonucleic acid) gene sequencing from the skin microbiome, using the Illumina MiSeq platform, the selection of primer to amplify regions for sequencing and we compare results with the current standard protocols. Methods DNA was obtained from two low density mock communities of 11 diverse bacterial strains (with and without human DNA supplementation) and from swabs taken from the skin of healthy volunteers. This was amplified using primer pairs covering hypervariable regions of the 16S rRNA gene: primers 63F and 519R (V1-V3); and 347F and 803R (V3-V4). The resultant libraries were indexed for the MiSeq and Roche454 and sequenced. Both data sets were denoised, cleaned of chimeras and analysed using QIIME. Results There was no significant difference in the diversity indices at the phylum and the genus level observed between the platforms. The capture of diversity using the low density mock community samples demonstrated that the primer pair spanning the V3-V4 hypervariable region had better capture when compared to the primer pair for the V1-V3 region and was robust to spiking with human DNA. The pilot data generated using the V3-V4 region from the skin of healthy volunteers was consistent with these results, even at the genus level (Staphylococcus, Propionibacterium, Corynebacterium, Paracoccus, Micrococcus, Enhydrobacter and Deinococcus identified at similar abundances on both platforms). Conclusions The results suggest that the bacterial community diversity captured using the V3-V4 16S rRNA hypervariable region from sequencing using the MiSeq platform is comparable to the Roche454 GS Junior platform. These findings provide evidence that the optimised method can be used in human clinical samples of low bacterial biomass such as the investigation of the skin microbiota

Additional file 1: Table S1. of Optimisation of methods for bacterial skin microbiome investigation: primer selection and comparison of the 454 versus MiSeq platform

Comparison of the relative abundance (%) of bacterial mock community at the classification level of family. Table S2a. Comparison of the relative abundance (%) of bacterial taxa from healthy human skin samples at the phylum level (data available for two samples for the V3-V4 primer pair and one sample for V1-V3 primer pair). Table S2b. Comparison of the relative abundance (%) of bacterial taxa from healthy human skin samples at the genus level (data available for two samples for the V3-V4 primer pair and one sample for V1-V3 primer pair). Skin sampling: Requirements for skin sampling and skin preparation instructions provided to healthy volunteers. (DOCX 40 kb

Association Between Genetic Variation in FOXO3 and Reductions in Inflammation and Disease Activity in Inflammatory Polyarthritis

This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/art.39760${\bf Background:}$ Genetic variation in FOXO3 (tagged by rs12212067) has been associated with a milder course of rheumatoid arthritis (RA) and shown to limit monocyte-driven inflammation through a TGFβ1-dependent pathway. This genetic association, however, has not been consistently observed in other RA cohorts. We sought to clarify the contribution of FOXO3 to prognosis in RA by combining detailed analysis of non-radiographic disease severity measures with an in vivo model of arthritis. ${\bf Methods:}$ Collagen-induced arthritis, the most commonly used mouse model of RA, was used to assess how Foxo3 contributes to arthritis severity. Using clinical, serological and biochemical methods, the arthritis that developed in mice carrying a loss-of-function mutation in Foxo3 was compared with that which occurred in littermate controls. The association of rs12212067 with non-radiographic measures of RA severity, including CRP, Swollen Joint Count, Tender Joint Count, DAS28 and the HAQ score were modelled longitudinally in a large prospective cohort of early RA patients. ${\bf Results:}$ Loss of Foxo3 function resulted in more severe arthritis in vivo (both clinically and histologically) and was associated with higher titres of anti-collagen antibodies and IL-6 in blood. Similarly, rs12212067 (a SNP that increases FOXO3 transcription) was associated with reduced inflammation – both biochemically and clinically – and with lower RA activity scores. ${\bf Conclusions:}$ Consistent with its known role in restraining inflammatory responses, FOXO3 limits the severity of in vivo arthritis and, through genetic variation that increases its transcription, is associated with reduced inflammation and disease activity in RA patients – effects that would lead to lesser radiographic damage.Arthritis Research UK (Grant ID: 20385)National Institute for Health ResearchWellcome Trust (Grant ID: 105920/Z/14/Z