209 research outputs found

    Corrosion behaviour of crystalline and amorphous forms of the glass forming alloy Fe43Cr16Mo16C15B10

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    The corrosion behaviour of both crystalline and largely amorphous forms of the Fe-based glass forming alloy, Fe43Cr16Mo16C15B10 alloy was investigated. Two different methods were used to induce transformation to the amorphous form of the alloy: laser melting and HVOF spraying. Both methods produced largely amorphous material, however the high brittleness of the alloy makes it susceptible to cracking during laser treatment, hence this technique is not suitable for largescale application. Potentiodynamic scanning showed that in 0.5M H2SO4 and 3.5% NaCl electrolytes both amorphous forms of the alloy had better corrosion resistance (lower current densities for -200 to +1000mV SCE) compared to the crystalline material. The laser treated material and HVOF coating performed similarly in 3.5% NaCl. In 0.5M H2SO4 the HVOF coating had a lower current density than the laser melted material for almost all of the potential range -300 to +1000mV SCE. The improved corrosion behaviour of the largely amorphous material is attributed to its homogeneity, and particularly to the elimination of the Mo-rich phase that underwent preferential corrosion in the crystalline form of the material

    Fretting wear behaviour of MoS2 dry film lubricant

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    Dry film lubricants (DFL) are used as palliative coatings to prevent fretting wear. In this work fretting tests are carried out on coated Ti6Al4V cylinders on coated flat samples under dry sliding conditions, using an amplitude of 300 µm, 2.5 Hz frequency and 575 N normal loads. During the tests the coefficient of friction (CoF) was monitored, with tests being terminated when the coefficient of friction reached 0.7. Wear scars were analysed by profilometry and SEM to elucidate wear mechanisms. Results show that CoF initially increases rapidly to 0.4, this is then followed by a plateau region that finishes in a sudden step decrease in CoF following which CoF rises steadily. This behaviour is shown to be characteristic and interrupted tests are presented to allow elucidation of the wear scar at different stages in the lifetime and thus aid an understanding of the mechanisms of degradation which control the tribological behaviour

    Grasses as Biofactories: Scoping out the Opportunities

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    Key points 1. Plant biopharming is set to dominate commercial recombinant protein expression for specific proteins. 2. The choice of plant species depends on a multitude of factors and is determined on a caseby- case basis. 3. As a leaf based expression system grasses would have to compete predominantly with tobacco and alfalfa. 4. The grass-endophyte symbiosis offers a number of unique possibilities for biopharming

    Grasses as Biofactories: Scoping out the Opportunities

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    Plant biopharming is set to dominate commercial recombinant protein expression for specific proteins. The choice of plant species depends on a multitude of factors and is determined on a case- by-case basis. As a leaf based expression system grasses would have to compete predominantly with tobacco and alfalfa. The grass-endophyte symbiosis offers a number of unique possibilities for biopharming

    The role of a thermally sprayed CuNiIn underlayer in the durability of a dry-film lubricant system in fretting: a phenomenological model

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    Dry film lubricant coatings (DFL) are employed to reduce friction and damage in highly loaded contacts. Metallic underlayers, e.g. CuNiIn, can be beneficial however, there is no detailed explanation of the mechanism. This work investigates the effect of CuNiIn on fretting of a MoS2-based DFL in a cylinder-on-flat contact with a fretting amplitude of 300 µm. Two test types were run: 1. DFL without CuNiIn; 2. DFL on the cylindrical sample and DFL with CuNiIn underlayer on the flat sample. The CuNiIn increased the system’s durability. A phenomenological model highlighting the important low friction and highly wear resistant interfacial material is developed. The increased durability is ascribed to the high roughness of the CuNiIn onto which the DFL was deposited

    DRD2/ANKK1 Taq1A (rs 1800497 C>T) genotypes are associated with susceptibility to second generation antipsychotic-induced akathisia

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    Although the advent of atypical, second-generation antipsychotics (SGAs) has resulted in reduced likelihood of akathisia, this adverse effect remains a problem. It is known that extrapyramidal adverse effects are associated with increased drug occupancy of the dopamine 2 receptors (DRD2). The A1 allele of the DRD2/ANKK1, rs1800497, is associated with decreased striatal DRD2 density. The aim of this study was to identify whether the A1(T) allele of DRD2/ANKK1 was associated with akathisia (as measured by Barnes Akathisia Rating Scale) in a clinical sample of 234 patients who were treated with antipsychotic drugs. Definite akathisia (a score ≥ 2 in the global clinical assessment of akathisia) was significantly less common in subjects who were prescribed SGAs (16.8%) than those prescribed FGAs (47.6%), p < 0.0001. Overall, 24.1% of A1+ patients (A1A2/A1A1) who were treated with SGAs had akathisia, compared to 10.8% of A1- (thus, A2A2) patients. A1+ patients who were administered SGAs also had higher global clinical assessment of akathisia scores than the A1- subjects (p = 0.01). SGAs maintained their advantage over FGAs regarding akathisia, even in A1+ patients who were treated with SGAs. These results strongly suggested that A1+ variants of the DRD2/ANKK1 Taq1A allele do confer an associated risk for akathisia in patients who were treated with SGAs, and these variants may explain inconsistencies found across prior studies, when comparing FGAs and SGAs

    Proinflammatory genotype is associated with the frailty phenotype in the English Longitudinal Study of Ageing

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    Background: Frailty is a state of increased vulnerability to poor resolution of homeostasis after a stressor event, which increases the risk of adverse outcomes including falls, disability and death. The underlying pathophysiological pathways of frailty are not known but the hypothalamic–pituitary–adrenal axis and heightened chronic systemic inflammation appear to be major contributors. Methods: We used the English Longitudinal Study of Ageing dataset of 3160 individuals over the age of 50 and assessed their frailty status according to the Fried-criteria. We selected single nucleotide polymorphisms in genes involved in the steroid hormone or inflammatory pathways and performed linear association analysis using age and sex as covariates. To support the biological plausibility of any genetic associations, we selected biomarker levels for further analyses to act as potential endophenotypes of our chosen genetic loci. Results: The strongest association with frailty was observed in the Tumor Necrosis Factor (TNF) (rs1800629, P = 0.001198, β = 0.0894) and the Protein Tyrosine Phosphatase, Receptor type, J (PTPRJ) (rs1566729, P = 0.001372, β = 0.09397) genes. Rs1800629 was significantly associated with decreased levels of high-density lipoprotein (HDL) (P = 0.00949) and cholesterol levels (P = 0.00315), whereas rs1566729 was associated with increased levels of HDL (P = 0.01943). After correcting for multiple testing none of the associations remained significant. Conclusions: We provide potential evidence for the involvement of a multifunctional proinflammatory cytokine gene (TNF) in the frailty phenotype. The implication of this gene is further supported by association with the endophenotype biomarker results

    Plant-Symbiotic Fungi as Chemical Engineers: Multi-Genome Analysis of the Clavicipitaceae Reveals Dynamics of Alkaloid Loci

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    The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some—including the infamous ergot alkaloids—have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species), a morning-glory symbiont (Periglandula ipomoeae), and a bamboo pathogen (Aciculosporium take), and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories of the epichloae, their protective roles as symbionts, and their associations with the highly speciose and ecologically diverse cool-season grasses
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